L López-Mir

A Sidibe

A López-Porta

E Pascual

O Font

B Dhuiège

G Depres

Towards In-mould Antennas for Geolocation Tags

Keywords: injection moulding, hybrid integration, printed electronics, antenna, wireless power transmission, geolocation

This paper presents a preliminary study for the construction of an in-mould smart tag as a robust flexible and battery-free label with a radiofrequency energy harvesting subsystem and enhanced geolocation features. The proposed flexible geolocation tag is realized by means of a specific production process applied over printed antennas and hybridized rigid control module. Advanced materials such as highly conductive inks and nanocellulose-based substrates, as well as innovative manufacturing processes covered by the inmould electronics framework, are investigated. Through simulations and experimental validation, the effect over printed antennas of an over-moulded layer of Thermoplastic Polyurethane (TPU) is explored. Such material due to its dielectric properties and thickness tends to down-shift the resonance frequency of the antenna, favouring miniaturization, but also increases its loss resistance. A 1.25 mm thick TPU was chosen for the final tag to ensure both flexibility and a realized positive gain of +0.7 dBi at 865 MHz. For further development of the tag, materials electrical and dielectric properties must be clearly defined in simulation to correct frequency shifts.

I. INTRODUCTION

Conventional tags based on Printed Circuit Board (PCB) with a protective casing limit the type of objects to be tracked according to their shape and surface material. The proposed in-mould flexible tag is intended to be attached to objects such as tools, vehicles, and parts in assembly lines compatible with curved surfaces for their geolocation. It is developed using inmould electronics (IME), prompted as a high-speed and competitive manufacturing methodology to ensure robustness and conformability of the tag. IME combines two dissimilar manufacturing processes, which are printed electronics and plastic processing, an already established high-volume production technology based on plastic injection and thermoforming [START_REF] Beltrão | A review on in-mold electronics technology[END_REF]. Polymer embedded antennas have been proven advantageous due to the enhanced protection towards harsh environments, temperatures, wetness and the lowpermittivity of polymers which make them a suitable option for higher-frequency applications [START_REF] Mohamadzade | Recent advances in fabrication methods for flexible antennas in wearable devices: State of the art[END_REF].

The battery-free solution to geolocate assets is proposed by Uwinloc, a company that develops and commercialises an indoor location solution. The tag is wirelessly powered thanks to an Ultra High Frequency (UHF) antenna that captures Electromagnetic (EM) waves in the European Radiofrequency Identification (RFID) frequency range from an RFID source. The accurate positioning signal is then transmitted by a UWB antenna with a centre frequency at 4 GHz [START_REF]ETSI standard[END_REF].

The key innovation of the tag is that it is obtained by a IME processing applied over printed antennas with a directly hybridized rigid control module both elements protected by an over-moulded superstrate. Customized highly conductive inks and substrate foils are developed while the inject moulding material is appropriately chosen to both have interesting radiofrequency transparency and flexibility. This work is a part of the MADRAS project [START_REF]MADRAS -Advanced materials and processing in organic electronics[END_REF], which is an European project to enable the future market deployment of flexible and wearable Organic Large Area Electronics (OLAE) based products.

II. ANTENNAS DESIGN THROUGH MATERIAL CHOICE

A. Device concept

The main constraint in any wireless device is the optimisation of the antenna to efficiently receive or transmit the signal. Therefore, the solution presented in MADRAS for the flexible geolocation tag is based on two antennas:

(1) The UHF antenna used for RF WPT on the frequency range between 865 MHz and 868 MHz.

(2) The UWB antenna to transmit the location signal at the centre frequency of 4 GHz (with a bandwidth higher than 20%) to dedicated beacons in the same area. The antennas will be connected to the RF input of a PCB electronic module that integrates a high efficiency RF to DC converter chip, a microcontroller and a UWB System on Chip (SoC). Figure 1 shows a preliminary schematic of the geolocation tag, consisting of a flexible foil based on nanocellulose with a combination of the two printed antennas and a small rigid module. These parts are integrated into a robust and flexible plastic piece through an over-moulding process. Apart from paving the path to mass production, the objective of the over-moulding is to add mechanical stiffness and protection to the vulnerable circuit elements and control module. In this paper, only the UHF antenna will be presented.

Fig. 1. 3D view of the in-mould geolocation tag. The module will be directly hybridized on the future versions of the two complex conjugate antennas. The electronic module is a 15 x15 mm all-in-one board.

B. Materials choice

The performance of antennas depends on the properties of the conductive ink, the dielectric properties of the surrounding materials, and the mismatch losses. For high efficiency antennas high conductive inks are required (less than 100 mΩ/sq of sheet resistance). Therefore, silver nanoparticle (Ag NP) ink for screen printing has been developed by Genes'ink due to its outstanding electrical properties compared to standard Ag µflakes inks (Table 1) [START_REF] Suzuki | Flexible Tactile Sensor Using Polyurethane Thin Film[END_REF][START_REF] Salmerón | Properties and Printability of Inkjet and Screen-Printed Silver Patterns for RFID Antennas[END_REF]. Two variants of Ag NP-based inks containing nanocellulose crystals -CNC with high conductivity (HC) and adhesion promoter (IA) were developed.

Concerning the substrate, the use of a nanocellulose-based foil (NCF) is proposed by Arjowiggins as a substitute of polymeric substrate with high recyclability and a very good oxygen barrier. The bare NCF substrate has a dielectric constant of 4.4 at 900 MHz and a dissipation factor of 0.15 at 1 kHz for a 60-µm thick foil.

Compatibility between Ag NP inks and NCF was firstly evaluated. Printed layers of the first customized Ag NP (HC) showed good adhesion to PET and paper substrates, but loose adhesion to NCF substrate. Then another version of Ag NP ink (IA) was adapted for suitable printability and adhesion on nanocellulose-based substrates. 5B adhesion (ASTM D3359 standard) was achieved with IA ink printed on NCF, though at the expense of a decrease in conductivity, as shown in Table 1, due to the presence of adhesion promoters. For a successful over-moulding procedure adhesion of the NCF with the chosen injected resin is essential. In order to increase their compatibility different coatings are tested on NCF, e.g. layers of Polyvinylidene Chloride (PVDC) or polyurethane (PU) [START_REF] Deavours | Effects of Antenna Material on the Performance of UHF RFID Tags[END_REF]. Concerning the injected resin, the most standard thermoplastic used for injection moulding of flexible plastic parts is Thermoplastic Polyurethane (TPU). Then compatibility between NCF and different grades of TPU, e.g. conventional or with higher peel strength values [START_REF]Estane-ZHF_95AT3.pdf[END_REF], is being evaluated.

III. IN-MOULD ANTENNAS MANUFACTURING

The in-mould antenna manufacturing process takes place at Eurecat's facility. An UHF antenna was screen printed on NCF with the two selected Ag NP inks and cut with a plotter into the shape fitting the chosen mould for plastic injection, as shown in Figure 2a.

Functional foils were over injected with TPU using a squared-shaped mould of 7 cm x 7 cm (Figure 2b) and two different thicknesses of 1.25 mm and 2.5 mm. Suitable injection flow rates, as well as pressure and temperature ranges, must be tuned to prevent washouts of the printed inks and warping [START_REF]AMC Straight PCB Jack Surface Mount 50 Ohm[END_REF]. To avoid excessive warping, various injection parameters were modified: lower holding pressure, higher holding pressure time and higher switch-over position. These parameters allow the polymer-NCF interface to release stresses before being injected from the mould. As a previous step to full integration of the control unit on the injected part, the resulting in-mould antenna is characterized using an external PCB with a U.FL connector [START_REF]AMC Straight PCB Jack Surface Mount 50 Ohm[END_REF]. As shown in Figure 2d, a U.FL connector (RF Connector AMC Straight PCB Jack Surface Mount 50 Ω) was welded on one side of a simple PCB, and the other side was hybridized on the printed antenna with conductive and structural adhesives. Prior to PCB hybridization, connecting paths filled with conductive epoxy resin between each side of the NCF were done, reinforced with connection pads (Figure 2c).

IV. ANTENNA DESIGN BY SIMULATION: EFFECT OF THE TPU

The design of antenna seeks two objectives: i) the overall size of the design should fit a 7 cm x 7 cm area and ii) the performance of the antennas must be optimised considering the insertion of a certain thickness of TPU. The design of the antennas by simulation has been carried out with Ansys HFSS software by Uwinloc, considering the presence of a TPU layer with different thicknesses over the printed UHF.

Theoretically, the dimensions of an antenna are related to the dielectric permittivity and the thickness of the used substrate. The higher the dielectric constant, the smaller the antenna as it affects the guided wavelength ( ). This is the wavelength of the signal propagating inside a transmission line. Its value in a microstrip transmission line (MTL) can be computed thanks to formula 1:

= / (1)
where is the speed of light, is the resonant frequency, and is the effective dielectric constant. The last is related to the width of the MTL and the height of the substrate. It can also be affected by different elements around (e.g., housing) according to their dielectric parameters. For the preliminary simulation, the dielectric parameters of the TPU found in [START_REF][END_REF] (relative permittivity εr = 4.8 and dissipation factor tanδ = 0.05) were considered. Electrical properties for printed layers (Table 1) and dielectric properties of NCF were determined and introduced into the simulations as well. Thereafter, printed and over-moulded prototypes were characterised and compared to the simulated values in order to optimise the simulation's model.

A. UHF antenna simulation

The UHF antenna under study obtained by simulation is represented in Figure 3. The antenna must present a 50 Ω input impedance to be characterised with a standard RF connector to avoid significant measurement inaccuracies and losses. The choice to use such a RF connector allows for easily validating the results on the antenna simulation with the dielectric properties of the materials obtained. The shape of the design is based on the antenna presented in [START_REF] Sidibe | Compact Antenna in 3D Configuration for Rectenna Wireless Power Transmission Applications[END_REF]. It was simulated without (wo) TPU and with TPU (1.25 mm and 2.5 mm thick) to predict the effect of the materials on the return loss and the radiation efficiency. A comparison of the simulated return loss (S11 in decibels (dB)) as function of the TPU thickness is presented in Figure 3. It is observed that the resonant frequency is downshifted by the TPU layer. This difference can be explained by the formula (1) where the guided wavelength is inversely proportional to the effective permittivity (function of the thickness). Therefore, the dielectric parameters of the TPU must be carefully characterised to have accurate simulation results. Table 1 shows the evolution of the radiation efficiency (ratio between the radiated power to the accepted power) at the desired frequency for the geolocation tag (866.5 MHz) with the TPU effect. This comparison is made on the UHF antenna printed with IA Ag NP ink on NCF substrate. It can be noticed that the radiation efficiency decreases with a thicker TPU layer at the same frequency. This difference is mainly due to the dielectric losses of the TPU given that the same substrate and same conductive ink are chosen. The reduction in efficiency is also observed at the resonant frequency of each sample (from +1.3 dBi without TPU to -0.8 dBi for with 2.5 mm thick TPU). Printed layer characteristics made of different inks (HC or IA) were also introduced in the simulation. As shown on the Table 3, the antenna with the IA ink is less efficient due to its higher resistivity (the accepted power is roughly the same for both inks). Nevertheless, it was concluded that this efficiency is sufficient for a good performance of the tag, although the lower the resistivity, the better for a competitive tag.

B. Antennas characterisation

The characterisation was performed in an anechoic chamber with the antenna placed on a Rohacell foam (εr ≃ 1; tanδ ≃ 0.001) to emulate the software simulation condition in free space. The measured return loss is obtained after SOLT calibration on the Vector Network Analyser Anristu 37397D. The results are summarized in Figure 4. A shift on the resonance frequency is observed due to the insertion of the TPU layer that is much more pronounced for the 2.5 mm-thick TPU over-layer in comparison with the 1.25 mm-thick case. Concerning the effect of TPU, the measurements are in good agreement with simulations: for thicker TPU, the resonant frequency of the UHF antenna is downshifted. The final geolocation tag will not work efficiently if the TPU layer changes the resonant frequency of the antenna. Hence, TPU parameters must be clearly defined on simulations before having an estimation of the antenna's performance. In fact, characterisation of each material properties used is required to obtain an accurate simulation without any significant difference in the matching and the radiation efficiency.

V. CONCLUSIONS

In this work, the feasibility of integrating a printed geolocation tag into a flexible plastic part through an innovative manufacturing process as is IME is demonstrated. The advanced materials proposed (NCF, Ag NP inks and TPU) constitute an appropriate assembly for the tag manufacturing in terms of both compatibility and appropriate antenna's performance. The use of TPU-over-moulding for antennas is interesting for miniaturization because of the guided wavelength modified by TPU dielectric permittivity. However, it can also induce loss and antenna radiation efficiency reduction.

Fig. 2 .

 2 Fig. 2. (a) UHF antennas printed on NCF; (b) Injection moudling set-up; (c) View from the backside of TPU over-moulded UHF antenna printed on NCF with exposed connection pads and (d) with hybridized PCB with U.FL connector.

Fig. 3 .

 3 Fig. 3. Proposed design with dimensions of the UHF Antenna (top); Simulated return loss of the UHF antenna as function of the TPU thickness (bottom).

Fig. 4 .

 4 Fig. 4. Measurement of the return loss of UHF Antenna considering the effect of TPU layer.

TABLE I .

 I ELECTRICAL PROPERTIES OF CONDUCTIVE LAYERS

	Ink name	Rsq	Resistivity	Thickness
		(mOhm/sq)	(µOhm.cm)	(µm)
	Ag µflakes ink	30-60	30•10 4	7-15
	Ag NP HC	22 ± 8	4.8 ± 0.8	2.3 ± 0.3
	Ag NP IA	130 ± 30	20 ± 1	1.7 ± 0.3

TABLE II

 II

	.	RADIATION EFFICIENCY AT 866.5 MHZ AND GAIN AT THE
	RESONANT FREQUENCY FOR DIFFERENT TPU THICKNESS OF THE UHF
		ANTENNA DESIGNS
	UHF	Radiation	Radiation Efficiency /
	antenna	Efficiency at 866.5	Realised Gain at the
	designs	MHz)	resonant frequency
	without TPU	73.7 %	88.8 % / +1.3 dBi (981 MHz)
	TPU 1.25 mm	73.1 %	73.3 % / +0.7 dBi (865 MHz)
	TPU 2.5 mm	62 %	61.9 % / -0.8 dBi (790 MHz)

TABLE III

 III

	.	SIMULATED POWER AND RADIATION EFFICIENCY OF THE
	ANTENNA FOR THE TWO FORMULATED INK
	Ink	Incident	Accepted	Radiation	Radiation
	name	Power	Power	Power	efficiency
	HC	30 dBm	29.9 dBm	29.62 dBm	93%
	IA	30 dBm	29.85 dBm	29.22 dBm	86%

ACKNOWLEDGMENT

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No. 862492.


Marc Teichmann
email: marc.teichmann@psl.aphp.fr

Clara Sanches

Julia Moreau

Sophie Ferrieux

Marie Nogues

Bruno Dubois

Meggane Cacouault

Saghie Sharifzadeh

Does surface dyslexia/dysgraphia relate

Keywords: semantic variant of primary progressive aphasia, surface dyslexia and dysgraphia, semantics, lexicon

Introduction

The semantic variant of primary progressive aphasia (sv-PPA) is a degenerative condition affecting the anterior temporal lobes and causing relatively selective damage to semantic representations [START_REF] Gorno-Tempini | Cognition and Anatomy in three variants of Primary Progressive Aphasia[END_REF][START_REF] Gorno-Tempini | Classification of Primary Progressive Aphasia and its variants[END_REF]. In the language domain, this condition leads to anomia, deficits in single-word comprehension, and, frequently, to surface dyslexia/ dysgraphia. The latter impairment is reflected by reading/writing errors with irregular words (also called exception words) for which the phoneme-grapheme correspondence is nontransparent (e.g., 'plaid' incorrectly read as "/pleId/" and written as "plad"), as opposed to regulars for which this correspondence is transparent (e.g., 'cat'). Written language has been much less explored in sv-PPA than oral language but surface dyslexia and dysgraphia have already been integrated in the most recent diagnosis criteria [START_REF] Gorno-Tempini | Classification of Primary Progressive Aphasia and its variants[END_REF], and they have causatively been attributed to impaired semantics [START_REF] Patterson | Deterioration ofword meaning: Implications for reading[END_REF][START_REF] Graham | The impact of semantic memory impairment on spelling: Evidence from semantic dementia[END_REF][START_REF] Woollams | SD-squared: On the association between semantic dementia and surface dyslexia[END_REF][START_REF] Caine | Emergence and progression of 'nonsemantic' deficits in semantic dementia[END_REF][START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF]; S.M. [START_REF] Wilson | The neural basis of surface dyslexia in semantic dementia[END_REF]M.A. Wilson et al., 2012;[START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF]. More specifically, it has been shown that reading errors with irregulars in sv-PPA patients correlate with their scores in the Pyramid and Palm Trees Test requiring semantic associations [START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF], and with their scores on picture naming tasks requiring lexical-semantic aptitudes [START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF]. Likewise, some authors have shown that reading errors with irregulars are correlated with cortical thickness measures of the anterior temporal lobe implementing semantics [START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF][START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF], and functional MRI in healthy adults has revealed that this region is activated during the reading of irregular words (M.A. Wilson et al., 2012;! 5 Hoffman et al., 2015;[START_REF] Provost | The effect of aging on the brain network for exception word reading[END_REF]. However, several studies have shed substantial doubt on this semantic-centered view by reporting patients who had massive semantic deficits without any surface dyslexia [START_REF] Schwartz | Dissociations of language function in dementia: A case study[END_REF][START_REF] Cipolotti | Semantic memory and reading abilities: a case report[END_REF][START_REF] Ralph | Semantic loss without surface dyslexia[END_REF][START_REF] Blazely | Semantic impairment with and without surface dyslexia: Implications for models of reading[END_REF][START_REF] Wilson | Semantic dementia without surface dyslexia in Spanish: unimpaired reading with impaired semantics[END_REF]. Recently, [START_REF] Playfoot | Reading and visual word recognition ability in semantic dementia is not predicted by semantic performance[END_REF] assessed two sv-PPA patients with different language tasks and did not find correlations between semantic impairment and difficulties in reading of irregular words.

Moreover, an investigation of sv-PPA cases has suggested that surface dyslexia in sv-PPA might not be related to semantic deficits but to lexical impairment [START_REF] Boukadi | Lexical decision with pseudohomophones and reading in the semantic variant of primary progressive aphasia: A double dissociation[END_REF].

In line with this controversy, the two most influential models of reading, namely connectionist and symbolic accounts, postulate two completely different mechanisms for dyslexia/ dysgraphia. The prototype of connectionist accounts is the triangular Parallel Distributed Processing (PDP) model [START_REF] Plaut | Understanding normal and impaired word reading: Computational principles in quasi-regular domains[END_REF], in which semantic, phonological/sound and orthographical patterns are directly interconnected via 'hidden layers/units', without any explicit implementation of lexical representations. The model claims that the processing of irregular words, especially of low-frequency irregulars, necessarily depends on a reading/ writing route involving semantics, while regular words can also be processed via a direct route from orthographical to sound patterns. This route is also crucial for novel or non-words which are exclusively processed via this direct pathway. Conversely, symbolic reading models and more particularly the Dual Route Cascaded (DRC) model [START_REF] Coltheart | DRC: A dual route cascaded model of visual word recognition and reading aloud[END_REF] state that, in addition to semantic, phonological/sound and orthographical patterns, there is an intermediate and explicit mental lexicon, which contains whole word forms. According to DRC models, this lexical level is critical to the processing of irregular words independently from semantics, mapping word entries in the orthographic lexicon directly onto word entries in the phonological lexicon, during reading, and vice versa during writing.

! 6

In sv-PPA the supposedly causative association of semantic failure and surface dyslexia/ dysgraphia is in line with PDP models. However, this causality is at odds with the DRC account predicting that sv-PPA patients also demonstrate critical damage to the orthographic or phonological component of the mental lexicon, which would be the causative factor for reading/writing errors with irregulars [START_REF] Coltheart | Computational modelling of the effects of semantic dementia on visual word recognition[END_REF]. In this controversial context, testing the reading/writing of irregular words in a cohort of sv-PPA patients along with contrastive tasks tapping item-specific semantic and lexical representations would allow for challenging the two models. Likewise, it would provide answers regarding the language components related to surface dyslexia/dysgraphia in sv-PPA by exploring the relationship between reading/writing of irregular words and lexical vs. semantic performances, on both a global correlative and an item-by-item basis.

Regarding tasks specifically tapping lexical representations, lexical decision paradigms (word vs. non-word) are claimed to be a reliable method as attested by computational simulations including computational models with sv-PPA-like lesions [START_REF] Coltheart | Computational modelling of the effects of semantic dementia on visual word recognition[END_REF]. Some connectionist network modellers, however, have suggested that lexical decision relies on the activation of semantic word knowledge (e.g., [START_REF] Woollams | SD-squared: On the association between semantic dementia and surface dyslexia[END_REF][START_REF] Dilkina | Are there mental lexicons? The role of semantics in lexical decision[END_REF]). It appears that the critical parameter which makes lexical decision about a real word a genuine lexical task is the nature of the non-words used in the task, namely their word-unlike characteristics (see e.g., [START_REF] Binder | Neural correlates of lexical access during visual word recognition[END_REF]. More specifically, some models assuming both lexical and semantic word codes suggest that, in lexical decision tasks, lexical representations are activated by words and by word-like non-words (e.g., [START_REF] Mcclelland | An interactive activation model of context effects in letter perception: Part 1. An account of basic findings[END_REF].

Such quasi-equal lexical activation levels would force the intervention of the semantic system allowing for deciding that a meaningful item is a word (YES answer in lexical decision) and that an item having no meaning is a non-word (NO answer in lexical decision). The parameter ! 7 of 'word-likeness' is reflected by the orthographical/phonological neighborhood size: noneighbor non-words are 'word-unlike' whereas multi-neighbor non-words are 'wordlike' [START_REF] Andrews | Frequency and neighborhood effects on lexical access: Lexical similarity or orthographic redundancy?[END_REF][START_REF] Coltheart | Computational modelling of the effects of semantic dementia on visual word recognition[END_REF]. Thus, only lexical decision tasks mixing real words and no-neighbor non-words would allow for specifically tapping the lexical level. This claim is also corroborated by a seminal work of [START_REF] James | The role of semantic information in lexical decisions[END_REF] who found faster lexical decision responses with semantically concrete than abstract words when mixing words with word-like (multi-neighbor) non-words. Such semantic effects totally disappeared when the non-words were unfamiliar letter strings (no-neighbor non-words). Similarly, [START_REF] Evans | What's in a word? A parametric study of semantic influences on visual word recognition[END_REF] found that semantic priming effects in lexical decision tasks increase in magnitude when the added non-words become progressively more word-like, as measured by their orthographical and phonological neighbor size.

In the present study, we therefore explored a cohort of sv-PPA patients using, in addition to reading and writing tasks, a lexical decision paradigm with stimuli comprising non-words without any orthographical or phonological neighbor to provide a reliable lexical marker.

Conversely, to directly assess semantic representations, and to diversify the tasks for the patients, we used category decision (living vs. non-living) to provide a semantic marker.

Importantly, the tasks included the same irregular word stimuli to allow for direct comparisons/correlations, and for item-by-item analyses of the consistency of reading/writing errors with item-specific category and lexical decision errors. This approach contrasts with previous studies on sv-PPA, which rarely assessed both reading and writing and/or did not use both lexical and semantic markers comprising the same stimuli for item-specific analyses with the exception of some rare studies exploring mainly single cases. With such a stringent approach, we aimed to determine whether sv-PPA patients demonstrate both semantic and lexical damage as predicted by DRC models, whether lexical or/and semantic deficits are ! 8 related to surface dyslexia/dysgraphia, and whether sv-PPA cohort-based data can provide novel support for either connectionist or symbolic models.

Methods

Participants

Twelve sv-PPA patients were included in the study at the National Reference Center for "PPA and rare dementias" of the Pitié Salpêtrière Hospital, Paris, France. Clinical diagnosis was based on a multi-disciplinary evaluation including neurological examination, standard neuropsychological tests and a detailed language evaluation. All patients satisfied the current consensus criteria for sv-PPA [START_REF] Gorno-Tempini | Classification of Primary Progressive Aphasia and its variants[END_REF]: they demonstrated isolated or highly predominant language disorders and had progressive single-word comprehension deficits and anomia. They did not have sentence repetition deficits, agrammatism or motor speech disorders. The diagnosis of sv-PPA was also imaging-supported given that all patients had atrophy on MRI affecting the anterior temporal lobes, with left hemispheric lateralization.

Patients did not present any neurological/psychiatric disease other than sv-PPA and they did not have non-degenerative lesions on routine MRI such as cerebrovascular disorders. Twentyfive healthy controls, matched with the patients for age and number of years of education were also included in the study (both Fs < 1). Healthy controls were tested with the Mini Mental State Examination (MMSE; [START_REF] Folstein | Mini-Mental State: a practical method for grading the cognitive state of patients for the clinician[END_REF] to ensure the normality of their cognitive abilities (mean score 28.9/30 ± 1.1; normal ≥ 27). They did not have any neurological disease or medical problem that could interfere with cognitive functioning. All participants were native French speakers. Demographic data are summarized in Table 1.

! 9
All data were generated during a routine clinical work-up and were retrospectively extracted for the purpose of this study. Therefore, according to French legislation, explicit consent was waived. However, regulations concerning electronic filing were followed, and patients and their relatives were informed that anonymized data might be used in research investigations.

The study received approval from the Ethics Committee of the Pitié Salpêtrière Hospital. The general cognitive assessment included among various standard tests the MMSE and the Frontal Assessment Battery (FAB; [START_REF] Dubois | The FAB, a frontal assessment Battery at bedside[END_REF]. The language assessment consisted of a picture naming test (D080; [START_REF] Deloche | Test de dénomination orale d'images[END_REF] and the Boston Diagnostic Aphasia Evaluation (BDAE; [START_REF] Mazaux | Boston Diagnostic Aphasia Examination[END_REF]. The BDAE included an evaluation of aphasia severity taking into account spontaneous speech and the description of the 'cookie theft picture', a sentence repetition task, and a single-word comprehension task requiring pointing to pictures upon auditory word presentation. We also applied a verbal fluency test comprising letter and category fluency [START_REF] Cardebat | Evocation lexicale formelle et sémantique chez des sujets normaux. Performances et dynamiques de la production en fonction du sexe, de l'âge et du niveau d'étude[END_REF]

Experimental Tasks

Reading and Writing tasks

The materials of the reading task included 30 irregular words for both reading and writing according to the irregularity criteria of Beauvois and Derouesné (Brain, 1981) (nouns corresponding to living and non-living entities). There were no homophones among the stimuli. They were contrasted with 30 regular words (nouns corresponding to living and non-! 12 living entities), which can also be processed via a direct route from orthographical to phonological patterns, and with 30 non-words the processing of which necessarily depends on this direct sublexical route. Participants were asked to read aloud the stimuli printed in black on white paper sheets (Times New Roman font, size 48).

For the writing task, the materials consisted of 15 irregular and 15 regular words (nouns corresponding to living and non-living entities), and of 15 non-words. The participants were asked to write-to-dictation the stimuli, which were auditorily presented by a native French speaker.

Within and between both tasks irregular and regular words were matched for frequency, number of letters and bigram and trigram frequencies (all Fs < 1), and non-words were matched for number of letters with the irregular and regular words (both Fs < 1) (LEXIQUE 2 database, [START_REF] New | Une base de données lexicales du français contemporain sur internet: LEXIQUE 2[END_REF].

Non-words did not have any orthographical or phonological neighbor and they were orthographically and phonotactically legal.

Lexical decision task

This task was designed as a marker for lexical representations. It contained a written/visual and an auditory version to assess two distinct access routes to abstract representations within the mental lexicon (orthographical and phonological codes), which were predicted to be correlated. The two versions of the task were used to explore access to the distinct components of the mental lexicon given that reading involves the orthographic input component followed by the phonological output component, whereas writing involves the phonological input component followed by the orthographic output component. In this vein, ! 13 our two versions of the lexical decision task probed for the integrity/breakdown of these four different lexical components.

Both versions contained 45 irregular words, 45 regular words and 100 non-words. The stimulus materials were the same for both versions and the irregular and regular items were identical to those used in the reading task, on the one hand, and in the writing task, on the other hand. Irregular and regular words were matched for frequency, number of letters and bigram and trigram frequencies (all Fs < 1). Non-words were matched with regular and irregular words for the number of letters (all Fs < 1). Importantly, non-words were matched for bigram frequencies with both regular words (t = 1.15, p = 0.254) and irregular words (t = -1.307, p = 0.194). Likewise, non-words were matched for trigram frequencies with both regular words (t = 1.3567, p = 0.179) and irregular words (t = -1.75, p = 0.083). Non-words did not have any orthographical or phonological neighbor. They were orthographically and phonotactically legal.

The stimuli were presented on a computer using E-prime software. In the written/visual version each trial began with a fixation cross (800 ms), followed by the stimulus word written in black (5000 ms). Between each trial there was a blank screen during 700 ms. In the auditory version each stimulus trial consisted in the presentation of a fixation cross (800 ms)

followed by an auditory target stimulus delivered through headphones. All words had been recorded by a female native French speaker and digitized for binaural headphone presentation using COOL EDIT software. In both versions the participants were asked to decide as accurately and as fast as possible whether the word target exists in French or not, by pressing the "YES" or the "NO" button on a computer keyboard. Participants answered by pressing "YES" or "NO" with the index finger and the middle finger of their dominant hand, ! 14

respectively. Before being tested on each version of the task participants were familiarized with the procedure by five training trials.

Category decision task

The task assessed whether a given written word refers, or not, to a living entity, and was conceived as a marker for semantic representations. In contrast to the lexical decision task we only used a written version because it is usually assumed that there are no distinct phonological or orthographical codes of semantic representations. This binary task of semantic capacities was used because the procedure, and the involved response mechanisms, are similar to the lexical decision task (word vs. non-word) given that YES/NO answers are also required for (living vs. non-living) decisions. The task takes also into account aspects of interactive models positing that the access to semantic features can be activated by orthographical/phonological features (e.g., [START_REF] Joanisse | Impairments in verb morphology following brain injury: A connectionist model[END_REF], even if hidden layers, which might reflect an equivalent of lexical representations, are degraded. More specifically, we included 32 words reflecting 'living' categories (e.g., "cat") and 64 words reflecting 'non-living' categories (e.g., "mat"), using 45 irregular words and 51 regular words.

The 45 irregular items, and the 45 regular items out of the 51, were exactly the same as those used in the lexical decision task, and as those used in the reading and writing tasks. Among the irregular words 20 corresponded to 'living' items and 25 corresponded to 'non-living' items. 'Living' and 'non-living' items were matched for frequency and number of letters (both Fs < 1). To ensure that our stimuli do not contain semantically ambiguous items regarding the living/non-living contrast we previously conducted a pilot study with 20 young healthy adults ! 15 who classified with high accuracy the living and non-living items (allover 98% of correct responses).

The stimuli were presented on a computer using E-prime software. Each trial began with a fixation cross (800 ms), followed by the stimulus word written in black (5000 ms). Between each trial there was a blank screen during 700 ms. Participants were asked to decide as accurately and as fast as possible whether the word target represents a 'living' entity or not, by pressing the "YES" or the "NO" button on a computer keyboard. Participants answered by pressing "YES" or "NO" with the index finger and the middle finger of their dominant hand, respectively. Before being tested on the task participants were familiarized with the procedure by five training trials.

The order of the experimental tasks was randomized. They were administered at 60-90 minute intervals to minimize potential cross-task biases given that they included the same irregular and regular word stimuli. To further minimize such biases the tests of the general cognitive and language assessment were administered during these intervals.

Statistical analyses

We first computed d' and c-values for the auditory and visual versions of the lexical decision task and for the category decision task in patients to assess the sensitivity of these tasks and possible response biases. Then, we used a mixed-effects model to look for differences between performances of sv-PPA patients and healthy controls, and to compare the different stimulus conditions within the experimental tasks. Linear mixed models were used to identify differences between reaction times (RT) on correct answers for sv-PPA patients and healthy controls in the auditory and visual versions of the lexical decision task and in the category ! 16 decision task. We then conducted Pearson's correlations assessing the relationship between performance in the lexical decision and the category decision task, to strengthen the claim that the two tasks tap distinct representations, namely lexical and semantic information. We also assessed the relationship between word frequency and RT in the lexical decision task to support that lexical access was occurring in this task. Correlation analyses were also used to explore the relationship between the reading/writing performances on irregular words and performance on these irregulars in the lexical decision task (lexical marker) and the category decision task (semantic marker). All these correlation analyses were conducted in patients and in healthy controls. Bonferroni correction for multiple comparisons was applied. In a second step we analyzed, on an item-by-item basis (consistency analyses), whether lexical decision errors and/or category decision errors on a given irregular word reliably predict errors on that item in the writing and the reading task. Finally, we conducted a multiple regression assessing the prediction of reading/writing errors with irregular words based on category decision and visual lexical decision measures with the aim to identify which of those two latter measures has the best power to explain reading/writing errors on irregulars.

Results

Sensitivity and response bias

Mean d' for the auditory and visual lexical decision tasks and for the category decision task were, respectively, 2.72, 2.55 and 1.13. All d' values were significantly different from '0' (all p < 0.001) indicating that patients were answering above the chance level. Mean c-values were 0.23 and 0.02 for the auditory and visual lexical decision tasks, respectively, showing a small bias towards 'YES' answers ('word exists') which was not significant. For the category ! 17 decision task patients also showed a non-significant bias towards 'YES' answers (mean cvalue = 0.07).

Analyses of the experimental tasks

All analyses were conducted with 'group' (sv-PPA, controls) and 'stimulus type' as fixed effects and 'subjects' and 'items' as random effects. Results of the reading and the writing task are illustrated in Figure 1. Results of the two versions of the lexical decision task and the results of the category decision task are illustrated in Figure 2. Mean values and standard deviations for patients and healthy controls, and for all tasks are illustrated in the Supplementary Tables 12345.

Reading task:

The stimulus types were 'irregular words', 'regular words' and 'nonwords'. A significant main effect of 'group' was found, with patients showing poorer performances than controls (p < 0.001). There was also a 'stimulus type' effect (p < 0.001) and a significant interaction between 'group' and 'stimulus type' (p < 0.001). Pairwise comparisons with Sidak adjustment for multiple comparisons showed that this interaction was related to the fact that patients had poorer performance with irregular words than with nonwords (p = 0.001) and regular words (p < 0.001) whereas controls demonstrated the inverse pattern for non-words (p = 0.029). Performance with regular words was better than with nonwords for controls (p = 0.001) whereas there was no difference between regular and irregular words. The comparison between controls and patients showed that irregular words yielded poorer performance in patients than in controls (p < 0.001) whereas performance with regular words and non-words was similar in patients and controls. Detailed statistical results are shown in Table 3.

! 18
Table 3 Mixed-effects model for the reading task (df = degrees of freedom)

Writing task:

We used the same stimulus types as in the reading task. A significant main effect of 'group' was found, with patients showing poorer performances than controls (p < 0.001). There was also a 'stimulus type' effect (p < 0.001) and a significant interaction between 'group' and 'stimulus type' (p < 0.001). Pairwise comparisons with Sidak adjustment for multiple comparisons showed that this interaction was related to the fact that patients had poorer performance with irregular words than with non-words, and performance with regular words was better than with irregular words and non-words (regular vs. irregular words: p < 0.001 regular words vs. non-words: p = 0.016). There was no difference between stimulus type for controls. The comparison between controls and patients showed that irregular words and non-words yielded poorer performance in patients than in controls (irregular words: p < 0.001; non-words: p = 0.017) whereas performance with regular words was similar in patients and controls. Detailed statistical results are shown in Table 4.

Lexical decision task:

The independent variables were "group" and "stimulus type" (regular words, irregular words). For the written/visual version, a significant main effect of 'group' was found, with patients showing poorer performances than controls (p < 0.001).

There was no stimulus type effect and no group x stimulus type interaction. Using reaction times (RT) as the dependant variable, there was a main effect of 'group', with patients showing slower RT than controls (p < 0.001). There was no stimulus type effect and no group

x stimulus type interaction. For the auditory version, there was also a main effect of 'group', with patients showing poorer performance than controls (p < 0.001). There was no stimulus type effect and no group x stimulus type interaction. Using RT as the dependant variable, there was a main effect of 'group', with patients showing slower RT than controls (p < 0.001).

There was no stimulus type effect and no group x stimulus type interaction. Detailed statistical results are shown in

Category decision task:

The independent variables were "group" (sv-PPA, controls), category ('living', 'non-living') and "stimulus type" (regular words, irregular words). A significant main effect of 'group' was found, with patients showing poorer performances than controls (p < 0.001). There was no category effect, no stimulus type effect and no interaction between the variables. Using RT as the dependent variable, there was a main effect of 'group', with patients showing slower RT than controls. There was no category effect, no stimulus type effect and no interaction between the variables. Detailed statistical results are shown in Table 6.

Pearson's correlation analyses

Correlation analyses were performed by extracting the mean performance (all items aggregated) for each participant for each of the tasks. The analyses were first conducted in patients which provide sufficient performance variability i) to explore whether the lexical markers (lexical decision scores) and the semantic markers (category decision scores) tap distinct language representations, i.e. lexical vs. semantic codes, and ii) to evaluate whether lexical and/or semantic markers are related to reading/writing failures with irregular words.

Correlation results are summarized in Table 7. In addition, we also conducted correlation analyses in healthy controls even if their performance variability and near ceiling-effects might make such correlations less informative and meaningful (see Table 8).

Regarding the first issue, performance of patients and of healthy controls in the auditory and written/visual lexical decision task were correlated, indicating that both tasks tap related, yet distinct representations within the mental lexicon containing orthographic and phonological codes. By contrast, performance in the category decision task did not correlate with those in the written/visual or the auditory version of the lexical decision task, with the exception of written/visual lexical decision in controls. In patients and controls there was a negative correlation between word frequency and response reaction times (RT) in the visual and in the auditory version of the lexical decision task i) for all word items, ii) for irregular items, and iii) for regular items (with the exception of auditory lexical decision in controls), supporting that lexical access was occurring in the task.

Regarding the second issue, reading performance of patients with irregular words was As for the category decision task, scores of the single-word comprehension test were not correlated with reading and writing performance on irregular words.

! 24

Item-by-item consistency analyses

In the patient group, we analyzed the consistency of errors for each of the irregular words between the reading and writing tasks, and the two versions of the lexical decision task and between the reading and writing tasks and the category decision task. This procedure allowed for determining the predictive value of the lexical task (lexical decision) and the semantic task The results showed that the item-specific consistency is high between the reading/writing errors with that item whereas semantic errors for a given irregular item are less predictive of reading/writing errors with that item.

Multiple regression model

A multiple regression was conducted using the number of reading/writing errors with irregulars as the dependent variable and category decision and visual lexical decision performances as explanatory variables. Auditory lexical decision was not included in the model as an explanatory variable since there is a high correlation between this measure and visual lexical decision, which would violate the multicollinearity assumption that requires that no strong correlation exists between explanatory variables in order to perform a multiple regression. Our multiple regression model statistically significantly predicted reading/writing errors with irregulars (F(2, 9) = 6.974, p = 0.01, adjusted R 2 = 0.521). In particular, only the visual lexical decision variable, but not the category decision variable, added statistically significantly to the prediction (p = 0.005). Regression coefficients and standard errors are shown in Table 9.

Discussion

We explored a cohort of sv-PPA patients to investigate whether surface dyslexia/dysgraphia is related to damage to the semantic system as proposed authors adhering to connectionist models or whether, in accordance with symbolic accounts, it is linked to impairments of the orthographic or phonological component of the mental lexicon. Concomitantly we investigated two directly related issues: whether sv-PPA patients demonstrate lexical damage in addition to semantic breakdown, and whether cohort-based sv-PPA findings can provide novel evidence supporting either symbolic or connectionist models. Our findings, based on reading/writing scores with irregular words, on lexical and semantic markers, and on the application of correlations, item-by-item consistency analyses, and a multiple regression model show i) that sv-PPA affects the mental lexicon, ii) that the lexical but not the semantic impairment correlates with markers of surface dyslexia/dysgraphia, iii) that lexical failure on a given irregular item reliably predicts reading/writing errors on that item, and iv) that lexical decision markers but not semantic category decision markers predict reading/writing errors with irregulars.

More specifically, our results showed that in sv-PPA reading and writing performance with irregular words was significantly lower than performance with regular words and non-words, ! 29 thus providing the signature of surface dyslexia/dysgraphia. Results from both the auditory and the written/visual version of the no-neighbor non-word controlled decision task revealed poor performance in sv-PPA, indicating lexical impairment. Importantly, trigram/ bigram frequencies were matched between irregular (and regular) words and non-words to avoid that lexical decisions might be made upon orthographical/sound features, as often stipulated by connectionist modelers, and to show that they rather depend on genuine lexical representations. There was also a negative correlation between word frequency and reaction times in both versions of the task for i) all items (regulars and irregulars combined), ii) for regulars, and iii) for irregulars. These results further corroborate that lexical access was occurring, and they justify the use of no-neighbor non-words which enabled participants to access word-specific knowledge rather than word meaning. Such lexical deficits concomitantly occurred with semantic breakdown as shown by massive impairment in the category decision task. The correlation analyses showed that reading/writing performance with irregulars was significantly related to lexical decision scores whereas there was no correlation with semantic-based category decision results. The link between surface dyslexia/ dysgraphia and lexical impairment was substantiated by the item-by-item analyses revealing a high item-specific consistency between reading/writing errors and lexical decision errors.

These analyses demonstrated a high positive predictive value (77.5%) indicating that lexical errors on an irregular item co-occur with reading/writing failure on that item. By contrast, semantic errors were poorer item-specific predictors of reading/writing errors (42.5%).

Finally, the multiple regression analysis showed that the lexical decision marker, but not the category decision marker, significantly predicts reading/writing errors with irregular words, thus reinforcing and extending our item-by-item analyses. Regarding correlations in our healthy control group with lexical or semantic markers it is probable that the lack of ! 30 significant results is simply related to the low performance variability in the healthy population yielding near-ceiling effects. this lack of correlations in healthy adults does not weaken our data or conclusions. Sv-PPA was explored because it represents a powerful model of semantic/lexical disorders and of reading/writing impairments with irregular words, thus allowing for elucidating the issue whether disorders with irregular words are predicted by semantic or lexical impairment, or both factors. Furthermore, sv-PPA patients demonstrate an exploitable variability of performance levels, thus allowing for meaningful correlation analyses which show that only lexical markers correlate significantly with performance on irregular words. However, future studies could explore the link between irregulars and semantic vs. lexical capacities in healthy participants by using more continuous markers/measures of reading/writing which might provide the necessary data variability as for example millisecond-measures of reading times for irregulars.

Our findings are in line with previous studies showing the existence of surface dyslexia in sv-PPA (e.g., [START_REF] Patterson | Deterioration ofword meaning: Implications for reading[END_REF][START_REF] Caine | Emergence and progression of 'nonsemantic' deficits in semantic dementia[END_REF], Brambati et al., 2009;M.A. Wilson et al., 2012), demonstrating poor performance on lexical decision in sv-PPA [START_REF] Graham | The impact of semantic memory impairment on spelling: Evidence from semantic dementia[END_REF][START_REF] Rogers | Natural selection: The impact of semantic impairment on lexical and object decision[END_REF][START_REF] Benedet | Non-semantic' aspects of language in semantic dementia: As normal as they're said to be?[END_REF][START_REF] Patterson | Presemantic" cognition in semantic dementia: Six deficits in search of an explanation[END_REF]Jeffries et al., 2010), and suggesting lexical disorders in this PPA variant [START_REF] Mesulam | Words and objects at the tip of the left temporal lobe in primary progressive aphasia[END_REF]2014;[START_REF] Wilson | What role does the anterior temporal lobe play in sentence-level processing? Neural correlates of syntactic processing in semantic PPA[END_REF][START_REF] Wilson | Lexical access in semantic variant PPA: Evidence for a post-semantic contribution to naming deficits[END_REF][START_REF] Boukadi | Lexical decision with pseudohomophones and reading in the semantic variant of primary progressive aphasia: A double dissociation[END_REF]. Our data extend and enrich previous evidence, and challenge several findings suggesting that surface dyslexia is specifically related to semantic breakdown (e.g., [START_REF] Macoir | Is surface dysgraphia tied to semantic impairment ? Evidence from a case of semantic dementia[END_REF][START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF]Wilson et al., 2012). First, unlike most investigations focusing primarily on surface dyslexia in sv-PPA, our study extends the processing failure on irregular words to the writing modality. Although some rare studies did find surface dysgraphia in sv-PPA [START_REF] Graham | The impact of semantic memory impairment on spelling: Evidence from semantic dementia[END_REF][START_REF] Macoir | Is surface dysgraphia tied to semantic impairment ? Evidence from a case of semantic dementia[END_REF][START_REF] Caine | Emergence and progression of 'nonsemantic' deficits in semantic dementia[END_REF][START_REF] Shim | Anatomic, clinical, and neuropsychological correlates of spelling errors in primary progressive aphasia[END_REF], they did not provide direct comparisons between ! 31

reading and writing with experimental materials using the same word stimuli. The only exception for such a direct comparison is the of [START_REF] Henry | Written language impairments in primary progressive aphasia: a reflection of damage to central semantic and phonological processes[END_REF] who included 6 sv-PPA patients within a cohort of 15 PPA patients, yet without providing statistical analyses of reading/writing data for the sv-PPA subgroup. Second, our results enrich and specify findings from previous lexical decision tasks, and proposals that sv-PPA entails lexical impairment,

given that investigations applying lexical decision paradigms in sv-PPA used word and nonword stimuli which could hardly demonstrate that low performance was related to lexical rather than semantic failure. In this context, the exclusive use of no-neighbor non-words in the present lexical decision design allowed for specifically assessing lexical representations [START_REF] Binder | Neural correlates of lexical access during visual word recognition[END_REF][START_REF] Coltheart | Computational modelling of the effects of semantic dementia on visual word recognition[END_REF], thus confirming the existence of genuine lexical impairment in sv-PPA. Furthermore, negative correlation between word frequency and reaction times in both versions of the lexical decision task for regulars and irregulars corroborate that lexical access occurs. The claim about lexical impairment is also consistent with our correlation analyses indicating that the lexical decision task and the category decision task tap distinct representations, i.e. lexical (orthographic or phonological) vs.

semantic information. More specifically, they showed significant correlation values between the auditory and the written/visual version of the lexical decision task whereas no correlation was found between lexical decision and category decision scores. This lexical/semantic distinction also holds for the item-by-item analyses showing that the co-occurrence of errors in the written/visual and auditory version of the lexical decision task was high (85%) whereas it was low for the lexical decision and the semantic-based category decision task (35%).

Third, our main finding challenges previous accounts assuming the causal role of exclusively semantic deficits in surface dyslexia, as our results have revealed a direct relationship ! 32

between reading/writing errors on irregular words and lexical markers, via both correlation and item-by-item consistency analyses.

These however, do not allow for inferring that semantics does not play a role in surface dyslexia/dysgraphia given that scores on the verbal version of the Pyramids and Palm

Trees Test slightly correlated with performance on irregular words in the reading and writing task. This is consistent with findings of [START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF] who also showed correlations between reading of irregulars and the verbal but not the picture version of the Pyramids and Palm Trees Test. Furthermore, in our study the item-specific consistency of reading/writing errors with semantic failure is not negligible, reflecting about 40% of concomitant semantic and reading/writing errors with irregulars. Nevertheless, this percentage is substantially lower than the item-by-item consistency between surface dyslexia/dysgraphia and lexical breakdown. Our results regarding item-by-item consistency are also in line with previous studies exploring such consistency in single cases [START_REF] Graham | The relationship between comprehension and oral reading in progressive fluent aphasia[END_REF][START_REF] Funnell | Response biases in oral reading: an account of the co-occurrence of surface dyslexia and semantic dementia[END_REF]Macoir and Bernoer., 2002;[START_REF] Blazely | Semantic impairment with and without surface dyslexia: Implications for models of reading[END_REF] or in small series of sv-PPA patients [START_REF] Mckay | The impact of progressive semantic loss on reading aloud[END_REF]. However, our cohort-based data add the information that item consistency is higher when analyzing lexical markers in addition to semantic markers. [START_REF] Blazely | Semantic impairment with and without surface dyslexia: Implications for models of reading[END_REF] reported that their patient had semantic impairments, as shown by performances on picture naming, single-word comprehension and word-picture matching tasks, along with surface dyslexia. This patient also showed impairments in a lexical decision task. However, while performances in the three semantic tasks correlated with each other, performances in the lexical decision task did not correlate significantly with performances in the semantic tasks.

These results suggest, as ours do, that impairment in lexical decision is driven also by impairments other than semantic ones. However, in this study the authors did not explore item-by-item consistency between reading errors with irregulars and any other task, which did ! 33 not allow for making inferences regarding the semantic vs. lexical mechanism underlying surface dyslexia in semantic dementia patients. Our cohort-based data the information that item consistency in reading/writing of irregulars is higher when analyzing lexical markers (lexical decision task) then when analyzing semantic markers.

One might wonder whether the category decision task, using the same irregular items as the lexical decision task, allows for assessing semantic knowledge on lexically rejected words (NO-answers in lexical decision). Strictly serial models state that the access to semantic representations critically depends on the fact that a given item has been activated in the mental lexicon. Interactive models however (e.g., [START_REF] Rumelhart | On learning the past tenses of English verbs: Implicit rules or parallel distributed processing[END_REF][START_REF] Joanisse | Impairments in verb morphology following brain injury: A connectionist model[END_REF] propose that degraded lexical representations allow for the activation of semantic information presumably via the involvement of an associative pathway directly connecting sound/letter patterns to semantic representations, eventually via 'hidden layers'.

Without presuming the existence of such a direct associative pathway, our data indicate that degraded lexical representations in sv-PPA, leading to NO-answers in lexical decision, can allow for accessing correct semantic category representations for a given item. They more specifically highlight that similar proportions of lexically rejected and lexically non-rejected items result in correct living/non-living categorizations (69% and 71%, respectively in the written version; 68% and 73%, respectively in the auditory version).

Reconciliation with connectionist-inspired literature on dyslexia/dysgraphia in sv-

PPA?

How can our findings be reconciled with previous studies attributing surface dyslexia to semantic breakdown and, anatomically, to damage to brain regions involved in semantic ! 34

processing? Regarding behavioral results on sv-PPA, most authors implicitly accepted connectionist accounts without contrasting them against symbolic models and their predictions. Apparently in line with such connectionist approaches, the available sv-PPA cohort studies have reported significant correlations between reading/writing of irregular words and standard tests of semantics such as the Pyramids and Palm Trees Test or picture naming tasks (e.g., [START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF][START_REF] Shim | Anatomic, clinical, and neuropsychological correlates of spelling errors in primary progressive aphasia[END_REF][START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF]. Our results

are compatible with such accounts stating that surface dyslexia/dysgraphia is related to semantic capacities as reflected by our item consistency analyses showing that 40% of semantic errors with a given item co-occur with reading/writing errors on that irregular item. However, item consistency was higher for lexical errors. The previous semantic-centered findings might in part be biased by the use of 'routine' tests which depend on multiple nonsemantic factors involving lexical aspects, as well as attention and executive factors which are minimized in our binary category decision task. In line with authors using such routine tests we replicated that scores on the verbal version, but not on the picture version, of the Pyramids and Palm Trees Test are slightly correlated with reading/writing with irregular words. One should note that this test is assumed to assess semantic performance but that its verbal version also depends on lexical access to the test items, requiring the complex processing of three words to find the association between two of them, while our task is a more direct semantic task that requires only the processing of one word at a time.

The most important point is, however, that no investigation on sv-PPA has provided direct comparisons between surface dyslexia and lexical vs. semantic markers, and no study has used item-specific consistency analyses for both lexical and semantic processing domains at a sv-PPA cohort level. Based on this stringent methodology we show that semantic failure plays a role, predicting surface dyslexia in almost half of the items, but we crucially provide novel ! 35 evidence that lexical impairment is a better predictor and a more important contributor to surface dyslexia/dysgraphia. The latter finding is consistent with several case studies which have reported that semantic breakdown in the explored sv-PPA patients was not associated with reading errors on irregular words [START_REF] Schwartz | Dissociations of language function in dementia: A case study[END_REF][START_REF] Cipolotti | Semantic memory and reading abilities: a case report[END_REF][START_REF] Ralph | Semantic loss without surface dyslexia[END_REF][START_REF] Blazely | Semantic impairment with and without surface dyslexia: Implications for models of reading[END_REF][START_REF] Wilson | Semantic dementia without surface dyslexia in Spanish: unimpaired reading with impaired semantics[END_REF]. Such results dissociating surface dyslexia and semantics have recently been strengthened by a study on two sv-PPA cases showing a double dissociation with respect to reading performance on irregular words and lexical decision with pseudohomophones, such as the non-word 'brane' derived from the real word 'brain' [START_REF] Boukadi | Lexical decision with pseudohomophones and reading in the semantic variant of primary progressive aphasia: A double dissociation[END_REF]. According to connectionist models, both lexical decision on such word-like non-words and reading of irregulars depend on the semantic system and therefore no dissociations between the two tasks are predicted. However, there was such a dissociation, and the authors thus propose that their data are compatible with DRC models containing lexical representations, allowing for double damage dissociations within the lexical system itself, which comprises interconnected orthographical and phonological components. In summary, we do not state that surface dyslexia/dysgraphia is unrelated to semantic competency but our data temper this relationship. They indicate that the relationship was probably over-weighted culminating in the widely assumed view that specifically semantic failure causes surface dyslexia/dysgraphia without exploring whether lexical disorders might be the major causative factor.

Regarding the anatomical correlates of surface dyslexia, imaging studies on sv-PPA have primarily implicated semantic-related regions of the temporal cortex, namely left anterior areas (e.g., [START_REF] Brambati | Reading disorders in primary progressive aphasia: A behavioral and neuroimaging study[END_REF]Wilson et al., 2012). However, in sv-PPA atrophy is mainly located in such anterior areas whereas more posterior temporal regions, implementing lexical representations (e.g., [START_REF] Kotz | Modulation of the lexicalsemantic network by auditory semantic priming: an event-related functional MRI study[END_REF][START_REF] Graves | Left posterior superior temporal gyrus participates specifically in accessing lexical phonology[END_REF]2010), demonstrate lower atrophy ! 36 variability. This pattern of atrophy in sv-PPA might constitute a bias in finding anatomofunctional correlations between surface dyslexia and brain regions other than anterior temporal regions, leading to non-significant correlation results with posterior temporal areas.

Despite this possible bias, and in line with our data highlighting the crucial role of the lexicon, a recent cortical thickness study with one of the largest sv-PPA cohorts (N=33) has

shown that more posterior temporal cortices are significantly correlated with surface dyslexia scores [START_REF] Binney | Reading words and other people: A comparison of exception word, familiar face and affect processing in the left and right temporal variants of primary progressive aphasia[END_REF]. In the same vein, [START_REF] Binder | Surface errors without semantic impairment in acquired dyslexia: a voxel-based lesionsymptom mapping study[END_REF] have shown surface dyslexia without semantic impairment in stroke patients and their data of voxel-based lesionsymptom mapping suggested "that the posterior middle temporal gyrus may compute an intermediate representation linking semantics with phonology". This so-called intermediate level represents presumably the mental lexicon which has been demonstrated to be implemented by such posterior temporal cortices (e.g., [START_REF] Kotz | Modulation of the lexicalsemantic network by auditory semantic priming: an event-related functional MRI study[END_REF][START_REF] Graves | Left posterior superior temporal gyrus participates specifically in accessing lexical phonology[END_REF]).

Nevertheless, the current antomo-functional uncertainty regarding surface dyslexia/agraphia encourages future imaging investigations using rigorously controlled stimulus materials for correlations in large cohorts of PPA patients and for functional MRI investigations in large populations of healthy adults.

Finally, a fundamental issue is whether our data are compatible with connectionist models of reading/writing such as the influential triangle PDP model (e.g., [START_REF] Plaut | Understanding normal and impaired word reading: Computational principles in quasi-regular domains[END_REF]. The model claims that semantic impairment causes surface dyslexia/dysgraphia, and that the mental lexicon does not play any role because, in their view, it does not exist. Our data are at odds with this line of models by indicating that lexical impairment is critically related to surface dyslexia and dysgraphia. Connectionist modelers could, however, claim that lexical decision tasks, including controlled experimental designs containing no-neighbor non-words, tap semantics, just as category decision tasks do. From this point of view, one should predict ! 37 significant correlations between the scores from both tasks (lexical decision and category decision), significant correlations between reading/writing of irregular words and both tasks, and item-specific consistency of reading/writing errors with error scores in both tasks. None of these predictions is validated by our data. By contrast, our results are in line with symbolic models such as DRC accounts proposing the existence of a mental lexicon and its major role in reading/writing deficits with irregular words [START_REF] Coltheart | Computational modelling of the effects of semantic dementia on visual word recognition[END_REF]. However, to adopt an equilibrated position, it should be mentioned that several connectionist models implement the notion of 'hidden layers' serving error back-propagation to adjust hidden layer units mediating between semantic, sound and orthographic features. Nevertheless, it has been argued that such hidden units might function as internal representations [START_REF] Pinker | On language and connectionism: analysis of a parallel distributed processing model of language acquisition[END_REF], representing in reality the equivalent of aspects of the mental lexicon, and which might computationally model some mechanisms linked to genuine lexical representations. Finally, it could be mentioned that various studies have investigated the existence of the mental lexicon showing its morphological, phonological and syntactic properties while demonstrating that these properties, and operations acting on them such as verb inflection, can not be fully simulated by connectionist hidden layer models (see e.g., [START_REF] Pinker | The past and future of the past tense[END_REF].

Conclusion

Our findings refine the knowledge about language deficits in sv-PPA indicating that it is not only characterized by semantic but also by lexical impairment, and demonstrating that the lexical impairment is a crucial factor for surface dyslexia and dysgraphia. Our results also provide novel patient-cohort-based support for symbolic models of reading/writing processes such as DRC accounts whereas they are less compatible with connectionist models.

Additional research is now required to specify the precise roles of semantic and lexical ! 38 competencies for reading/writing in healthy subjects and patients, to enrich models of written language, and to clarify the linguistic targets of rehabilitation strategies. ! 47

Figure legends

  significantly correlated with scores in the written/visual and in the auditory version of the ! 23 lexical decision task. By contrast, there was no correlation between reading scores and scores in the category decision task. Likewise, writing performance with irregulars was correlated with scores in the written/visual version and in the auditory version of the lexical decision task. Conversely, no correlation was found between the scores on irregulars and the scores in the category decision task. In controls there were no significant correlations probably due to ceiling effects, with the exception of writing performance with irregular words and performance in the visual lexical decision task. In addition, we conducted correlation analyses with two standard test of semantics: the Pyramids and Palm Trees Test and the single-word comprehension test of the BDAE. Scores of the verbal version but not of the picture version of the PPTT were correlated with reading and writing performance on irregular words. Scores of the Pyramids and Palm Trees Test did not correlate with values of the category decision task. Scores on single-word comprehension correlated significantly with the scores of the experimental category decision task indicating that our task genuinely assesses semantic capacities constituting the main criterion for sv-PPA diagnosis (Gorno-Tempini et al., 2011).

(

  category decision) for reading/writing errors on irregular words. More specifically, we calculated 1) the number of item-specific co-occurring reading/writing errors and lexical decision errors (written/visual version) on irregular words divided by the total number of errors on irregulars in the written/visual version of the lexical decision task, 2) the number of item-specific co-occurring reading/writing errors and lexical decision errors (auditory version) on irregular words divided by the total number of errors on irregulars in the auditory version of the lexical decision task, 3) the number of item-specific co-occurring reading/ writing errors and category decision errors divided by the total number of errors on irregulars in the category decision task.

Figure 1

 1 Figure 1 Performance of sv-PPA patients and healthy controls in the reading and writing

Figure 2

 2 Figure 2 Performance of sv-PPA patients and healthy controls in the lexical decision task

Table 1

 1 Demographic data of healthy controls and sv-PPA patients SD =

standard deviation 2.2. General cognitive/language assessment controls (mean ± SD) sv-PPA (mean ± SD) Number of subjects 25 12 Sex (women, men)

		13W/12M	8W/4M
	Age (years)	65.8 ± 8.6	66.4 ± 7.2
	Handedness (R/L)	25R/0L	12R/0L
	Years of education	13.4 ± 3.4	12.9 ± 4.3
	Symptom duration (years)	///////	3.5 ± 2.1
			! 10

sv-PPA (mean ± SD) Normal threshold MMSE (/30) 23

	Table 2 Cognitive/language scores of sv-PPA patients
			and a semantic matching test in
	its verbal and picture version (Pyramids and Palm Trees Test; Howard and Patterson, 1992).
	Cognitive/language scores are summarized in Table 2.
	SD = standard deviation. MMSE = Mini Mental State Examination. FAB = Frontal
	Assessment Battery. BDAE = Boston Diagnostic Aphasia Examination. DO80 =
	Picture naming task. PPTT = Pyramids and Palm Trees Test. Normal thresholds are
	calculated as a function of normative values according to the age, sex and educational
	level of our patient population.	.7 ± 3.5	≥ 27
	FAB (/18)	14.7 ± 2.9	≥ 16
	BDAE -aphasia severity scale	3.1 ± 0.8	> 4
	BDAE -single-word comprehension	59.3 ± 4.1	≥ 68
	BDAE -sentence repetition	15.1 ± 3.4	≥ 14
	Category fluency ('fruits' / 2 minutes)	9.9 ± 5.0	≥ 15
	Letter fluency ('P' / 2 minutes)	13.8 ± 8.5	≥ 15
	DO80 (/80)	39.5 ± 15.8	≥ 75
	PPTT verbal (/50)	33.9 ± 9.7	≥ 45
	PPTT pictures (/50)	34.7 ± 9.3	≥ 45
			! 11

Table 4

 4 Mixed-effects model for the writing task (df = degrees of freedom)

	Source	Numerator df	Denominator df	F-value	p-value
	Intercept	1	100.210	2566.660	<0.001
	Group	1	35.000	30.86	<0.001
	Stimulus type	2	88.762	8.723	<0.001
	Interaction	2	3202.000	77.548	<0.001

Table 5a

 5a Table 5a and 5b.

	Source	Numerator df	Denominator df	F-value	p-value
	Intercept	1	55.996	2104.967	<0.001
	Group	1	35.000	82.972	<0.001
	Stimulus type	2	44.648	25.704	<0.001
	Interaction	2	1582.000	108.861	<0.001
					! 20

Mixed-effects model for performances in the visual version of the lexical decision task (df = degrees of freedom)

Table 5b

 5b Mixed-effects model for performances on the auditory version of the lexical decision task (df = degrees of freedom)

	Source	Numerator df	Denominator df	F-value	p-value
	Intercept	1	47.769	7590.323	<0.001
	Group	1	35.800	35.479	<0.001
	Stimulus type	2	204.196	1.453	0.236
	Interaction	2	6802	0.668	0.513
	Source	Numerator df	Denominator df	F-value	p-value
	Intercept	1	56.993	10680.742	<0.001
	Group	1	35.594	52.413	<0.001
					! 21

Table 6

 6 Mixed-effects model for performances in the category decision task (df = degrees of

	freedom)

Table 7

 7 Pearson's correlation results between the different measures for sv-PPA patients

	Correlated measures	R	p-value
	Auditory lexical decision / Visual lexical decision	0.86	0.0003
	Category decision / Visual lexical decision	0.29	0.35
	Category decision / Auditory lexical decision	0.28	0.38
	Word frequency (total) / Visual lexical decision RT	-0.31	0.003
	Word frequency (regulars) / Visual lexical decision RT	-0.38	0.009
	Word frequency (irregulars) / Visual lexical decision RT	-.052	<0.001
	Word frequency (total) / Auditory lexical decision RT	-0.3	0.005
	Word frequency (regulars) / Auditory lexical decision RT	-0.36	0.015
	Word frequency (irregulars) / Auditory lexical decision RT	-0.34	0.0023
	Reading (irregulars) / Visual lexical decision	0.82	0.001
	Reading (irregulars) / Auditory lexical decision	0.69	0.009
	Reading (irregulars) / Category decision	0.38	0.39
			! 25

Table 9

 9 Summary of multiple regression analysis

	Variables	B	SEB	β
	Intercept	117.661	24.693
	Category decision	-0.170	0.117	-0.315
	Visual lexical decision	-0.902	0.243	-0.803*
				! 28

Acknowledgments

This work was supported by funding from the program "Investissements d'avenir" ANR-10-IAIHU-06 (Agence Nationale de la Recherche-10-IA Agence Institut Hospitalo-Universitaire-6).

! 39


HIEBS Sylvie Démurger

Martin Fournier
email: fournier@gate.cnrs.fr

Li Shi

Urban income inequality in China revisited (1988-2002)*

Keywords: Inequality, China, Spatial price-deflators, Inequality decomposition. JEL: C8, D3, R1

Using newly available spatial price deflators, this paper shows that inequality evaluations in the literature overstate the magnitude of inequality and inequality changes in China, as well as the role played by regional differences in the observed inequality rise during the 1990s.

Introduction

The rise of inequality in China has been extensively documented by a growing literature that stresses the central role played by regional differences (Griffin and Zhao 1993, Gustafsson and Li 2001, Khan and Riskin 2001, Riskin et al. 2001, World Bank 1997).

However, up to recently, a key variable was missing in these evaluations: consumer prices differences across regions and provinces. Yet, evidence of regional market segmentation in China (Young, 2000; Wederman, 2003) suggests that price differences are quite strongly correlated with nominal income differences across provinces, and therefore that inequality studies may be strongly and systematically biased. In this note, we evaluate the magnitude of these biases for urban household disposable income inequality over the 1988-2002 period, by using new data constructed by Brandt and Holz (2005), which provide for the first time valuable and reliable estimations of consumer prices at the provincial level.

Data

The data used in this paper come from three household income surveys conducted by the China Project of Income Inequality organized by the Institute of Economics, Chinese Academy of Social Sciences with assistances from the National Bureau of Statistics (NBS),

for the reference periods of 1988, 1995 and 2002. The sample in each survey was drawn from a large-scale sample selected by NBS for its annual household survey 1 . The sample size is 1 The sampling method of NBS's surveys is briefly described in NBS (2002, p. 318).

rather large, 9,009 households for 1988, 6,931 for 1995, and 6,835 for 2002. The data from the three surveys are usually refered to as the CHIP (China Income Project) data 2 .

For space limitation reasons, we restrict our analysis here to the income variable proposed by Khan and Riskin. The variable has a broader coverage of income components than the income variable adopted by NBS, since it also takes into account income in kind, housing subsidies and imputed rent of private housing 3 . However, all our results on the sensitivity of inequality measures and decompositions to the use of provincial price deflators are robust to the use of narrowly defined household income variables of the NBS type.

Moreover, we only present inequality in urban household disposable income using the square root of the total number of household members as the equivalence scale, though all results are robust to alternative hypotheses 4 .

To analyze the inter-regional dimension of urban inequality, we use the standard grouping for the eleven provinces included in the urban survey for the three years: the coastal region (Beijing, Guangdong, Jiangsu and Liaoning), the central region (Henan, Anhui, Hubei and Shanxi), and the western region (Gansu, Sichuan and Yunnan).

In the analysis that follows, incomes are adjusted for provincial purchasing power differences by using Brandt and Holz (2005) urban provincial-level spatial price deflators 5 .

This newly created dataset is based on the meticulous analysis of household expenditures and prices for a base year, 1990, which is then extended over the 1984-2002 period using provincial consumer price indexes. Although they may still be subject to some measurement 2 See Griffin and Zhao (1993), Riskin, Zhao and Li (2001) and Khan and Riskin (2005) for further details on the data.

3 For a detailed discussion of the income definition and computation procedure, see Griffin and Zhao (1993), and Khan and Riskin (2001). 4 Including the two extreme cases of no equivalence scale and household income per capita. 5 The reference is nationwide prices in 2002.

errors 6 , these data provide without any doubt a reliable evaluation of provincial prices, and fill a major gap in the study of inequality in China.

Urban inequality in China: 1988-2002

Table 1 presents inequality changes over the 1988-2002 period for various inequality indexes with and without deflating household disposable income by provincial price indexes.

If the dramatic inequality rise over the 1988-1995 period has been largely documented 7 , the reversed evolution for the 1995-2002 period may be less common knowledge. The finding of slightly but significantly decreasing inequality has been analyzed in details by Khan and Riskin (2005) who show that its major sources are the drop in inter-provincial inequality and changes in the distribution of subsidies while, at the same time, wage income became more unequalizing 8 .

Table 1 clearly shows that inequality levels are quite substantially over-evaluated when price differences are not taken into account. Indeed, inequality computed from nondeflated income is between 7% and 20% higher than that observed for deflated income 9 . This issue, which has already been documented by Benjamin, Brandt and Giles (2005) 10 and Benjamin, Brandt, Giles and Wang (2005) 11 on different periods and databases is confirmed here for urban household disposable income using the CHIP data. It provides per se a major motivation to use regional price deflators in any analysis of income inequality in China.

Moreover, Table 1 stresses the dynamics of the over-evaluation phenomenon. Indeed, not only can the levels of inequality usually presented in the literature be misleading but 6 In particular, they rely strongly on the official provincial CPI for years other than 1990, which may lead to systematic biases and the impact of differences in housing prices may still be under evaluated since only construction costs are taken into account. 7 See in particular Riskin et al. (2001) and World Bank (1997).

8 Standard NBS income measures, which fail to incorporate an important part of household subsidies in kind, do not show this trend. Going further in the debate would go far beyond the scope of this note. 9 All biases are statistically significant at the 5% level. 10 For rural China, using data from the Research Centre for Rural Economy (RCRE).

11 For urban and rural China, using data from the China Health and Nutrition Study (CHNS).

evaluations of inequality changes may also be substantially biased. For all inequality indexes considered here, the magnitude of the bias substantially decreases between 1988 and 1995, leading to a potential under-evaluation of the magnitude of the increase in inequality over this period 12 .

Spatial urban income inequality decompositions: static biases

Tables 2 and3 provide standard inequality decompositions by sub-groups for the two most commonly used decomposable inequality indexes, the Theil index and the Mean Log Deviation Index (MLD). Our results clearly confirm that the regional dimension, stressed by most analyses of inequality changes in China, is a key factor in explaining urban inequality.

However, they also indicate that its contribution is much over-evaluated if household income is not deflated by provincial prices. Indeed, the absolute contribution of inter-regional inequality to overall inequality is over-evaluated by between 64% and 200% depending on the inequality index and the year considered 13 , and the absolute contribution of interprovincial inequality is over-evaluated by between 90% and 300% 14,15 .

Spatial urban income inequality decompositions: dynamic biases

Concerning the dynamics of inequality, Tables 4 and5 clearly show that the spatial dimension stressed in the literature remains a clear and robust source of inequality changes.

Indeed, observed inequality changes can be attributed in a sizeable part to the evolution of inequality between regions and even in a larger part to inter-provincial inequality changes.

12 Observed decreases in the bias are however weakly statistically significant (at the 15% level for Gini, Theil and MLD and not significant for GE(-1)). 13 Respectively, the relative contribution of inter-regional inequality is over-evaluated by between 45% and 200%. 14 Respectively, the relative contribution of inter-provincial inequality is over-evaluated by between 65% and 250%. 15 Biases are statistically significant at the 5% level in all cases.

Here again, using provincial price deflators may also substantially modify the magnitude of evaluated effects. Indeed, over the 1988-1995 period, inequality decompositions based on non-deflated incomes greatly overstate the role of inter-provincial inequality [START_REF]Biases are statistically significant at the 5% level for the provincial dimension. They are however weakly significant for inter-regional inequality contributions[END_REF] . Since, as mentioned above, the observed inequality rise is under-evaluated, this in turn leads to an under-evaluation of the rise in the relative contribution of the provincial dimension to overall inequality.

Findings for the 1995-2002 period confirm the central role played by the reduction of inter-provincial and inter-regional inequalities in the observed decrease in urban household income inequality already documented by Khan and Riskin (2005). However, using provincial price deflators does not significantly influence differently the evaluation of the role played by inter-provincial and inter-regional inequalities.

Conclusion

This note stresses the importance of taking into account prices differences across provinces when evaluating inequality and analyzing the sources of inequality changes in China. We show that inequality evaluations proposed in the literature tend to overstate the magnitude of inequality as well as the role played by regional differences in the observed inequality rise of the 1990s.

Table 1 Household total disposable income inequality: 1988-2002

 1 Notes: 1. The equivalence scale used is the square root of the total number of household members.2. Standard errors in italics are computed from a 300 replications bootstrap procedure.

			1988		1995		2002
		Not deflated	0.208	0.002	0.321	0.009	0.304	0.003
	Gini	Deflated	0.191	0.002	0.298	0.010	0.284	0.003
		Bias (%)	8.9	0.5	7.7	0.6	7.1	0.3
		Not deflated	0.079	0.003	0.234	0.033	0.157	0.004
	Theil index	Deflated	0.065	0.002	0.211	0.035	0.134	0.003
		Bias (%)	20.3	1.6	11.5	3.4	16.6	0.8
	Mean Log	Not deflated	0.074	0.002	0.179	0.012	0.155	0.003
	Deviation	Deflated	0.063	0.002	0.157	0.013	0.136	0.002
	index (MLD)	Bias (%)	17.0	1.1	13.9	1.6	13.7	0.6
	General
	Entropy	Not deflated	0.081	0.003	0.240	0.026	0.184	0.004
	Index (e = -1)	Deflated	0.071	0.003	0.214	0.026	0.163	0.003
		Bias (%)	14.2	1.1	12.1	1.5	12.6	0.6

Table 2 Group decomposition of household income inequality by region

 2

					Absolute "between" contribution			Relative "between" contribution (%)
				1988	1995	2002	1988		1995		2002
			Not deflated	0.0085	0.0008	0.0334	0.0042	0.0266	0.0022	10.84	1.03	14.25	3.25	16.95	1.19
	Theil index	Deflated	0.0025	0.0005	0.0203	0.0033	0.0137	0.0014	3.76	0.74	9.62	2.63	10.17	0.97
			Bias	0.0061	0.0007	0.0131	0.0042	0.0129	0.0020	7.09	1.13	4.63	2.01	6.78	1.47
	Mean Log	Not deflated	0.0085	0.0008	0.0328	0.0040	0.0259	0.0022	11.43	1.04	18.35	2.54	16.71	1.19
	Deviation		Deflated	0.0025	0.0005	0.0201	0.0033	0.0134	0.0014	3.88	0.74	12.76	2.05	9.80	0.95
	index (MLD)	Bias	0.0060	0.0007	0.0128	0.0041	0.0125	0.0019	7.56	1.13	5.59	2.01	6.90	1.42
	Notes:	See table 1.

Table 3 Group decomposition of household income inequality by province Absolute "between" contribution Relative "between" contribution (%) 1988 1995

 3

	2002	1988	1995	2002

Table 4 Share of inequality changes due to inter-regional inequality changes

 4

	(%)			1988-1995	1995-2002
			Not deflated	15.98	2.76	8.77	6.12
	Theil index	Deflated	12.26	2.32	8.65	4.72
			Bias	3.72	2.82	0.13	6.21
	Mean Log	Not deflated	23.23	3.91	29.04	19.03
	Deviation	Deflated	18.74	3.49	32.14	16.83
	index (MLD)	Bias	4.49	4.12	-3.10	20.38
	Notes:	See table 1.

Table 5 Share of inequality changes due to inter-provincial inequality changes

 5

	(%)		1988-1995	1995-2002
		Not deflated	28.07	3.22	26.04	7.52
	Theil index	Deflated	18.53	3.13	22.04	6.37
		Bias	9.54	3.83	4.00	8.03
	Mean Log	Not deflated	37.25	4.09	73.03	21.19
	Deviation	Deflated	26.73	4.46	74.29	21.52
	index (MLD)	Bias	10.52	5.02	-1.26	23.89

Notes:

See table 1.