Pauline Maillot
email: pauline.maillot@u-psud.fr.

CIAMS Alexandra Perrot

Alan Hartley

Effects of Interactive Physical-Activity Videogame Training on Physical and Cognitive Function in Older Adults

Keywords: physical activity, aging, video game, cognition, exergames

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Effects of Interactive Physical-Activity Videogame Training on Physical and Cognitive Function in Older Adults

A ubiquitous observation in studies of human aging is that cognitive abilities differ between young and elderly adults in a number of neurocognitive domains such as reasoning, attention, memory, and processing speed (e.g., Craik & Salthouse, 1999;[START_REF] Hoyer | Memory aging[END_REF][START_REF] Park | Aging, cognition, and culture: a neuroscientific perspective[END_REF][START_REF] Salthouse | What and When of Cognitive Aging[END_REF]. Nevertheless, epidemiological work suggests that in old age a lifestyle rich in mental, physical, and social stimulation could have beneficial influences on the level of cognitive performance (e.g., [START_REF] Hultsch | Use it or lose it: engaged lifestyle as a buffer of cognitive decline in aging[END_REF][START_REF] Kramer | Environmental influences on cognitive and brain plasticity during aging[END_REF]. Generalized transfer is relatively rare in studies of learning but there is clear evidence that regimens involving physical activity training or video game playing can result in improved cognitive function in older adults (e.g., Green & Bavelier, 2008;[START_REF] Green | Perceptual learning during action video game playing[END_REF][START_REF] Spence | Video games and spatial cognition[END_REF]. Exercise adherence is a particular challenge with older adults (Chao, Foy, & Farmer, 2000), but video game playing is increasingly popular among middle-aged and older adults (e.g., [START_REF] Flew | Games: Technology, industry, culture[END_REF]. Products that have recently become available support entertaining video games that combine game play with significant physical exercise by using physical input devices (e. g., Nintendo Wii and Microsoft Xbox 360 Kinect). We will call these exergames. There has been a rapid growth of the popularity of exergames, including among the elderly (e.g., [START_REF] Vance | Technology, cognitive remediation, and nursing: Directions for successful cognitive aging[END_REF]. The purpose of the present study was to assess the potential of exergame training based on physically-simulated sport play as a mode of physical activity that could have cognitive benefits for older adults. If exergame play has the cognitive benefits of conventional physical activity and also has the intrinsic attractiveness of videogames, then it might be a very effective way to induce desirable lifestyle changes in older adults.

Physical Activity and Cognition

The relationship between physical activity and cognition has been examined empirically with cross-sectional designs (e.g., [START_REF] Clarkson-Smith | Relationships between physical exercise and cognitive abilities in older adults[END_REF][START_REF] Hillman | Physical activity and cognitive function in a cross-section of younger and older community-dwelling individuals[END_REF][START_REF] Perrot | Physical activity as a moderator of the relationship between aging and inductive reasoning[END_REF][START_REF] Shay | Association between aerobic fitness and visuospatial performance in healthy older adults[END_REF] and with physical training interventions (e.g., [START_REF] Dustman | Aerobic exercise training and improved neurophysiological function of older adults[END_REF][START_REF] Hawkins | Aging, exercise and attention[END_REF][START_REF] Kramer | Ageing, fitness and neurocognitive function[END_REF]. It has also been approached from neuroscience perspectives [START_REF] Colcombe | Neurocognitive aging and cardiovascular fitness: recent findings and future directions[END_REF][START_REF] Erickson | Aerobic exercise effects on cognitive and neural plasticity in older adults[END_REF]. The results of meta-analytic reviews have established that the beneficial effects of physical activity participation on cognitive performance in older adults are reliable, with one review reporting an effect size (ES, [START_REF] Cohen | Statistical power analysis for the behavioral science[END_REF] that was moderate in size (ES = 0.48 using [START_REF] Hedges | Estimation of effect size from a series of independent experiments[END_REF] formula; [START_REF] Colcombe | Fitness effects on the cognitive function of older adults: A meta-analytic study[END_REF] and another reporting a small to large effect (ES = 0.10 to 1.17; using the Weighted Mean Difference and Standardised Mean Difference; [START_REF] Angeraven | Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment[END_REF]. Additionally, Colcombe and Kramer indicated that larger effects of aerobic exercises (ES = 0.41) and combined training (aerobic with strength exercises; ES = 0.59) were evident for executive function tasks (ES = 0.68) than for either processing speed tasks (ES = 0.27), visuospatial-awareness tasks (ES = 0.43), or controlled cognitive tasks (ES = 0.46). Empirical studies have largely focused on aerobic exercise, based on the presumed role of cardiovascular fitness as a potential mechanism, in the relationship between cognitive decline and physical activity (e.g., [START_REF] Chodzko-Zajko | Physical fitness, cognitive performance, and aging[END_REF][START_REF] Colcombe | Neurocognitive aging and cardiovascular fitness: recent findings and future directions[END_REF][START_REF] Kramer | Ageing, fitness and neurocognitive function[END_REF]. However, findings from the meta-analytic reviews suggest that cardiovascular fitness is not the only mechanism of the effect [START_REF] Angeraven | Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment[END_REF][START_REF] Colcombe | Fitness effects on the cognitive function of older adults: A meta-analytic study[END_REF][START_REF] Etnier | A meta-regression to examine the relationship between aerobic fitness and cognitive performance[END_REF]. This then allows the possibility that increases in cardiovascular fitness are not necessary for cognitive benefits, and, consequently other forms of physical activity that do not particularly emphasize improvements in cardiovascular fitness should be explored for their possible cognitive benefits. As we noted, there is also an underlying issue. Although the effects of physical activity on cognitive vitality are widely recognized in popular culture, resistance to exercise among the elderly remains very high (U.S. Department of Health and Human Services, 1996). This is presumed to be due to the unattractiveness and inaccessibility of physical activity as well as to functional restrictions (i.e., reduced cardiorespiratory endurance, reduced resistance strength, weight gain) related to advancing age (e.g., Hughes, Seymour, Campbell, Whitelaw, & Bazarre, 2009;[START_REF] Schutzer | Barriers and motivations to exercise in older adults[END_REF].

Video Games and Cognition

Training regimens based on sedentary video games can improve cognitive skills (e.g., [START_REF] Achtman | Video games as a tool to train visual skills[END_REF]Green & Bavelier, 2008;[START_REF] Green | Perceptual learning during action video game playing[END_REF]. The benefits of video games for cognitive performance have been demonstrated in younger adults primarily in cross-sectional studies comparing game players with non-game players on visuospatial attentional functions (for a review, see [START_REF] Green | Effects of action video game playing on the spatial distribution of visual selective attention[END_REF] and on attention, memory, and executive control functions [START_REF] Boot | The effects of video game playing on attention, memory, and executive control[END_REF].

In older adults, it has been observed that after several weeks of video game training elderly game players showed improvements when compared with control groups on reaction time (e.g., [START_REF] Clark | The effects of videogame playing on the response selection processing of elderly adults[END_REF][START_REF] Goldstein | Videogames and the elderly[END_REF], manual dexterity [START_REF] Drew | Video games: Utilization of a novel strategy to improve perceptual motor skills and cognitive functioning in the non-institutionalized elderly[END_REF], visuomotor coordination [START_REF] Dustman | The effects of videogame playing on neuropsychological performance of elderly individuals[END_REF] and executive control functions such as task switching, working memory, visual short-term memory and reasoning [START_REF] Basak | Can training in a real-time strategy videogame attenuate cognitive decline in adults?[END_REF]. However, there are reasons to question whether there is general transfer of video game play to cognitive domains. [START_REF] Ackerman | Use it or lose it? Wii brain exercise practice and reading for domain knowledge[END_REF] had a sample of adults between the ages of 50 and 71 complete 20 1-hr training sessions over the course of one month using the Nintendo Wii Big Brain Academy, a completely sedentary activity. The results indicated substantial improvements on the Wii tasks themselves, but there was no significant transfer of training from the Wii practice to more measures of fluid and crystallized intelligence and perceptual speed abilities, administered before and after the month of cognitive training activities. Although a positive relation between video game training and cognition has been demonstrated, it would seem that the transfer of the video game training to measures of cognition is not systematic, but rather may depend on several aspects of the training such as task difficulty, motivation and arousal, feedback, and variability (cf., Green & Bavelier, 2008). Moreover the type of video games employed could have an important effect on whether transfer of training is observed. For example [START_REF] Basak | Can training in a real-time strategy videogame attenuate cognitive decline in adults?[END_REF] did not obtain the same improvements for visuospatial skills using a real-time strategy game that Green andBavelier (2003, 2006) had obtained with action video games. The characteristics of the game itself could be directly related to the types of processes that are modified by playing the game (e.g., [START_REF] Achtman | Video games as a tool to train visual skills[END_REF] meaning that transfer is not as general as claimed. The results of previous training programs using video games provide us with no clear guidance for predictions in the present study. It is possible that video game training results in general transfer only when physical activity is involved.

Exergames and Cognition

Exergames, like the sports that they simulate, make both physiological demands for increased energy expenditure [START_REF] Graves | The physiological cost and enjoyment of Wii Fit in adolescents, young adults, and older adults[END_REF] and cognitive demands [START_REF] Quiroga | Video-games: Do they require general intelligence[END_REF]. For example, both in tennis and in a simulation such as Wii Tennis, one must run to the ball and strike it and, at the same time, calculate where to place the return for maximum advantage. We know that physical exercise has broad cognitive benefits, perhaps even if cardiovascular fitness is not improved. Video game playing may have cognitive benefits, but even it if does not, it is highly motivating and likely to promote exercise adherence. We are aware of only two studies using exergames. [START_REF] Rosenberg | Exergames for subsyndromal depression in older adults: A pilot study of a novel intervention[END_REF] found a reduction in depressive symptoms and improvement in mental health-related quality of life and in a measure of global cognitive functioning after 35 min session three times weekly for 12 weeks although the critically important untrained control group was not included. Nitz, Kuys, Isles, and Fu (2009) found improved balance and lower limb muscle strength after 30 min sessions twice weekly for 10 weeks. To our knowledge, no study has examined the impact of exergames on cognitive functioning in older adults.

The Present Study

The purpose of the present study was to determine whether exergame training in physically-simulated sport activity would show transfer to cognitive functions in older adults.

To examine this issue, we developed an active video game training program using a pretesttraining-post test design comparing an experimental group (24x1hr of training) with a control group without treatment. We selected the Nintendo Wii gaming system owing to its accessibility for novice and older populations, the relevance of the games to actual sport, and its ready availability in the marketplace of commercial software. In order to maximize the physiological challenge and keep the spirit of physical activity, only games of physicallysimulated sport were selected on this exercise program: Wii Sports, Wii Fit and Mario & Sonic on Olympic Games.

We tested two main hypotheses. The first was that exergame training would result in improved performance on the Wii sports tasks themselves. The second was that there would be practice-related improvements on a wide range of neuropsychological tests, including executive control tasks, visuospatial tasks and processing speed tasks. On the basis of previous findings of transfer effects for physical activity, we expected that the exergames program would lead the benefits on measures of executive control (e.g., [START_REF] Colcombe | Fitness effects on the cognitive function of older adults: A meta-analytic study[END_REF][START_REF] Kramer | Ageing, fitness and neurocognitive function[END_REF]. Further, to the extent that exergames make mental demands similar to those of sedentary video games we expected, on the basis of the findings of practice effects for video games, that performance on visuospatial tasks (e.g., [START_REF] Green | Action video games modify visual selective attention[END_REF], 2006) and on processing speed tasks (e.g., [START_REF] Clark | The effects of videogame playing on the response selection processing of elderly adults[END_REF][START_REF] Drew | Video games: Utilization of a novel strategy to improve perceptual motor skills and cognitive functioning in the non-institutionalized elderly[END_REF][START_REF] Dustman | The effects of videogame playing on neuropsychological performance of elderly individuals[END_REF][START_REF] Goldstein | Videogames and the elderly[END_REF] would be enhanced. Because we were not certain that Wii games would be sufficiently challenging to produce a change in cardiovascular fitness, we did not make a prediction about changes in physical function.

Method

Participants

Potential participants were contacted through flyers posted in town halls and community senior centers. People responding were contacted by phone and they provided an estimation of their physical activity, video game use and health status. All potential participants also rated their health on a 5-point health scale (1 = very bad, 2 = bad, 3 = fair, 4 = good, 5 = excellent), and those who rated their health as very bad or bad were excluded. We included only those individuals who reported never playing video games and living a sedentary lifestyle. We based our selection criteria on the recommendations of several health guides (including the Canadian Health Network in Canada and the Institut National de Prévention et d'Education pour la Santé in France).

Thirty-two independently-living older adults (27 women, 5 men, between 65-78 years) recruited from the region of Paris, France, volunteered to take part in this longitudinal intervention study. All participants were of European, Caucasian origin and were native French speakers. They gave their informed consent, and were not compensated for their participation. Each participant was required to have a medical certificate permitting the practice of physical activity. All participants were right-handed and had normal or correctedto-normal vision and audition. The participants completed the Mini-Mental Status Examination [START_REF] Folstein | The Mini-Mental State Examination[END_REF], the Geriatric Depression Scale [START_REF] Yesavage | Development and validation of a geriatric depression screening scale: a preliminary report[END_REF][START_REF] Yesavage | Development and validation of a geriatric depression screening scale: a preliminary report[END_REF], and the Modifiable Activity Questionnaire (MAQ, [START_REF] Kriska | Development of questionnaire to examine relationship of physical activity and diabetes in Pima Indians[END_REF] which assesses current (past-year) physical activity for different activity categories practiced at least training group and 16 other participants were assigned to a no-training no-contact control group. Over the course of the study, one participant in the training group gave up on the third training session reporting that it was physically too difficult. One control participant could not attend the post test session owing to medical problems unrelated to the study. Accordingly, the analysis of results of this study was based on the 15 individuals remaining in each group. 1. There were no significant differences between the two groups in age, years of education, body mass index, or scores on the MMSE, GDS, and MAQ.

Demographic information for both groups is listed in Table

Apparatus

For the exergame training we used the Nintendo Wii, a video game console with motion-sensitive technology. The Wii Remote and the Nunchuk, the primary wireless controllers for the console, use a combination of built-in accelerometers and infrared detection to sense their positions in three-dimensional space when pointed at LEDs within the console's Sensor Bar. This design allows game players to control their avatars (graphical representations of the user) using physical gestures as well as traditional button presses. We used also the Nintendo Wii Balance Board which has a similar shape to a body-weight scale, with a flat rectangular platform 51.1cm wide by 31.6cm long by 5.3 cm deep. Four force sensors record the weight of the player and the trajectory of the center of pressure of the participant during the game. It communicates wirelessly with the Nintendo Wii video game console. The video game display was a LCL projector (Panasonic Model PT-AX200E) projecting on a portable screen (Epson ELPSC06) 76 cm in height and 102 cm in width.

Measures

The Functional Fitness Battery

The physical impact of training program was evaluated by performance on a functional fitness battery, by heart rate measures (in beats per minute, bpm), and by ratings of perceived effort. The functional fitness battery measures the physiologic capacity to perform normal everyday activities safely and independently without undue fatigue [START_REF] Rikli | Development and validation of a functional fitness test for community-residing older adults[END_REF]. We used the Senior Fitness Test (SFT, [START_REF] Rikli | The surprising history of the "HRmax=220-age" equation[END_REF] which measures the underlying physical parameters associated with functional ability and which identifies whether an older adult may be at risk for loss of ability to perform functional movements such as walking, stair climbing, and standing up. The SFT protocol comprises seven components completed in 30 to 40 min following a 5 min warm-up exercise. Height (m) and body weight (kg) were measured in order to calculate Body Mass Index (BMI, kg/m 2 ). The chair-stand test measures muscle strength for lower body, and the arm curl test measures upper body strength.

The 6-Minute Walking Test (6MWT) evaluates cardio-respiratory fitness. The number of meters walked, the maximum heart rate, the mean heart rate, and the rated exertion using the modified [START_REF] Borg | Psychophysical bases of perceived exertion[END_REF] Karvonen (1957). Heart rate reserve (HRR) is the difference between the estimated maximum heart rate (MHR = 205 -0.685 x Age) and the RHR. There are various formulas to estimate MHR; this one is recommended as the most accurate univariate estimate in a thorough review by Robergs and Landwehr (2002). For any exercise bout with heart rate HR E , the proportion of HRR used is calculated as (HR E -RHR)/HRR. Finally at end of the 6MWT and after every training session, participants were asked to score their perceived exertion using the Borg scale.

The Cognitive Battery

The battery included a number of tasks that fell into three categories: executive control [START_REF] Corrigan | Relationships between parts A and B of the Trail Making Test[END_REF], originating from the Army Individual Test Battery, is a timed paper-and-pencil task that consists of two separate parts. Part A involves drawing a line to connect consecutive numbers (i.e., from 1 to 2 to 3 and so on up to 25). Part B requires the participant to connect numbers and letters in an alternating progressive sequence (i.e., 1 to A to 2 to B and so on). Without lifting their pencil from the paper, participants began at number 1 and connected the circles in the instructed order as quickly as possible without making any errors. If an error was made, the experimenter indicated the error and allowed the participant to correct the mistake and continue the task. The measure is the time to complete. Because Part A of the Trail Making Test has been viewed as primarily a measure of speed, the measure we used in our analyses was the time for Part B less the time for Part A. Following [START_REF] Corrigan | Relationships between parts A and B of the Trail Making Test[END_REF], we reasoned that the difference would be a purer measure of executive function.

Stroop test. The Stroop test (Stroop, 1935), is a frequently used measure of executive function; we used a modified version [START_REF] Bohnen | Modification of the Stroop Color Word Test improves differentiation between patients with mild head injury and matched controls[END_REF][START_REF] Chatelois | Stroop Flexibilité-4 couleurs[END_REF]. Participants are required to verbally identify the color of the stimulus in each of four conditions. In the congruent color-naming condition, the stimulus is string of symbols printed in colored ink, such as a series of red Xs. In the color-reading condition, the stimulus is a color name written in black ink. In the incongruent condition, the stimulus is a color name printed in a different ink color, such as the word "blue" printed in red ink. Finally, in the flexibility condition, the stimuli are the same as in the congruent condition except that the participant reads the color word rather than the ink color if the stimulus has a border. In all conditions, the number of correct answers given in 45 sec was the measure of performance.

Color-naming and color-reading conditions are task-training conditions that were not included in the analysis. Only the incongruent and flexibility conditions were used as measures of the executive functioning.

Letter Sets test. Participants were given 15 items each containing five sets of letters (e.g., NOPQ DEFL ABCD HIJK UVWX) and had to choose the set that did not follow the rule defined by the four other sets. The Letter Sets test was taken from the Educational Testing Service (ETS) Kit of factor-referenced cognitive tests [START_REF] Ekstrom | Manual for the kit of factor-referenced cognitive tests[END_REF]. The score was the number of items correctly completed in 13 minutes.

Matrix Reasoning test. This test consists of a sequence or group of designs, in which the individual is required to choose the one design from a number of choices that correctly completes the sequence. This test is a subtest of Wechsler Abbreviated Scale of Intelligence (1999) and measures abstract nonverbal reasoning ability. The score was the number of items correctly completed.

Digit Symbol Substitution test. Participants were provided with key matching digits to various symbols and were asked to write in the appropriate symbol for each digit to several rows of digits. The score was the number of correctly coded digits completed in 120 sec. The Digit Symbol Substitution test originated from the WAIS-R (Wechsler, 1997a).

Visuospatial Tasks

Spatial Span test. The Spatial Span test is a subtest of the Weschler Memory Scale [START_REF] Wechsler | Wechsler Memory Scale -3 rd Edition (WMS-III)[END_REF]. The apparatus consists of ten blue wooden blocks 3.1 cm square fixed to a 20 cm by 25 cm white, wooden board. The blocks are numbered on the sides facing the examiner as a means of facilitating administration and recording of the path sequences. The blocks are tapped in a predetermined sequence by the examiner using the eraser end of a pencil at the rate of one block per second, and participants are required to reproduce the block-tapping sequences when the stimulus sequence is completed by touching the appropriate blocks. This procedure continues with increasing numbers of blocks touched until the participant cannot correctly reproduce the sequence. The score is the largest number correctly reproduced. The backward Spatial Span test is exactly the same except that the participant must reproduce the sequence in reverse order. Directional Headings test. This is a speeded paper and pencil test of spatial ability [START_REF] Cobb | A proposed new test for aptitude screening of air traffic controller applicants (FAA-AM-72-18)[END_REF]. Each item comprises three pieces of information that reflect cardinal points on a compass (e.g., the letter "W", a symbol "←", and the notation "270", each denote "West"). The individual is asked to determine the direction indicated (if all information is consistent), or indicate that the information is inconsistent. The score is the number of correct items in 60 sec.

Mental

Processing Speed Tasks

Cancellation test. This is a perceptual speed test [START_REF] Ackerman | A correlational analysis of skill specificity: Learning, abilities, and individual differences[END_REF] Plate Tapping test. The Plate Tapping test, a part of the Eurofit Testing Battery, is a response speed test using an alternating tapping action which measures upper body reaction time, hand-eye quickness, and coordination [START_REF] Bovend'eerdt | MOPER fitnesstest: Handleiding en Prestatieschalen (12-18 jarigen)[END_REF].

Two green discs (20 cm diameter) are placed with their centers 60 cm apart on a table and a rectangle (30 by 20 cm) is placed equidistant between both discs. One hand is placed on the rectangle. The subject moves the other hand back and forth over the hand in the middle alternately tapping the two discs as quickly as possible. This action is repeated for 30 seconds.

The score is the number of taps. Participants had two trials with each hand, the mean scores were recorded.

Procedure

The entire study spanned 14 weeks. This included the pre-training (first week) and post-training (fourteenth week) sessions for assessment and, for the training group, the training sessions. Participants completed a battery of neuropsychological tests, assessing executive control functions (five tests with a total of six measures), visuospatial functions (three tests with a total of four measures), and processing speed functions (four tests with a total of eight measures), in order to measure the cognitive impact of the program and a battery of functional fitness tests in order to measure the physical impact of program. Each time, the cognitive battery and the functional fitness batteries were administered over two days within one week, with a 90 minute session each day. The 12 cognitive assessments tasks were presented in the following fixed order: On the first day, performance on executive control and processing speed tasks was assessed; on the second day, performance on visuospatial tasks and functional fitness were assessed.

Participants in the training group completed two 1-hr exergame sessions per week over a period of 12 weeks, resulting in total training time of 24 hr. Each participant was paired with another for each session with the intention of making the exergame playing more enjoyable and motivating adherence to the regimen. Participants were asked not to play exergames, except for this study. Each session began with a warm-up and finished with a cool-down in order to reduce the risk of injury (e.g., [START_REF] Jones | Case report: Injuries associated with interactive game consoles: preliminary data[END_REF].

Each training session was divided into three periods. During the first period, participants played in pairs at the Wii Tennis or Wii Boxing game alternating each session.

Only on the first, twelfth and twenty-fourth sessions, they played at the Wii Bowling game.

During the second period, participants took turns using the balance board to play the Wii Soccer Headers, the Wii Ski Jump, and the Wii Marbles games. During the final period, participants played four games on which we recorded performance: Wii Ski Slalom, Wii Hula Hoop, Wii Trampoline, and Wii Tennis Return of Serve. We classified each of these four tasks based on the primary skill required: The Ski Slalom game requires balance; the Hula Hoop game requires energy and stamina; the Trampoline game requires cognitive judgment; and the Tennis game requires a variety of skills so we classified it as global.

For the balance task (Ski Slalom), the participants "slalomed" by shifting their weight to alternate between blue and red doors as quickly as possible. The performance score is a function of the time to complete the course and the numbers of door cleared. For the energy task (Hula Hoop), the score was the number of successful rotations of the hoop in 70 sec. For the cognitive task (Trampoline), the participants achieved up to 10 points by making the indicated movements for optimal control of the avatar. For the global task (Tennis Return of Serve), the score was the number of serves from the computer's ball machine successfully returned before an error occurred.

Each training session was supervised by a physical trainer. The coach's functions were (a) to implement the training schedule and give any necessary explanations, (b) to ensure the safety of the participants and particularly to prevent the risk of fall, (c) to prevent participants from using incorrect postures or movements or cheating movements, and (d) to give participants feedback on their performance and note their exercise adherence. The participants were urged to try to increase the level of challenge and to improve their performance on each activity over the course of the training. At the end of the training program, the participants completed a questionnaire that measured their subjective impression of the program. Six questions were asked, two in the form of 5-point scales on the similarity between the exergame session and conventional forms of physical activity (1 = very much, 2 = much, 3 = relatively, 4 = not much, 5 = none), and on the difficulty of the training sessions (1= very easy, 2 = easy, 3 = reachable, 4 = difficult, 5 = very difficult), and four other yes-no questions on whether their body knowledge had improved, whether they would like to continue an exergames practicum, whether they would like to begin a program of physical activity, and whether they would like to acquire an exergame game console.

The participants in the control group committed themselves not to modify their sedentary lifestyle and not to begin playing video exergames games or engage in other physical activity over the 14 weeks of the study.

Results

The first step in the analysis was to verify that the training and control groups were equivalent at the outset of the program. T tests were used to compare the pre-training scores on both physical and psychological measures for those who would later be assigned to the training and control groups. The descriptive and inferential statistics are given in Table 2.

Among the 35 comparisons, only one was significant. Those who would be assigned to the training group rated the 6-min walk as more taxing than those who would be assigned to the control. Because there was only this one difference and that in a subjective assessment, we deemed the two groups equivalent. The central step in the analysis was to determine whether the training regimen resulted in greater change in the trained group than the untrained controls. We calculated the change score by subtracting the pretest score from the posttest score for each measure. First, we explored the possibility of test-retest improvement in the control group using one-group t tests to test the observed change against zero. There was no significant change. In order to determine whether the change was significantly greater in the trained group than in the controls we used the following approach: First, we carried out a MANOVA with all the measures within a set as dependent variables; then, if the overall difference between treatment and control was significant, we carried out t tests on each of the component measures, using the modified Bonferroni procedure to protect against an inflated chance of a Type I error [START_REF] Holm | A simple sequentially rejective multiple test procedure[END_REF]. The first set of comparisons was for measures of physical performance. The descriptive and inferential statistics for those change scores are given in Table 3. Physical improvement was significantly greater in the treatment group, Wilk's Λ = .31, F(10, 18) = 4.06, p = .005, η² = .693. The Borg Scale judgments of exercise intensity for the 6-min walk, which are subjective measures, were omitted from this analysis. Follow-up tests showed that greater improvement in the training group than in the controls was observed for all the physical measures except the Back-Scratch measures of flexibility. With unprotected tests, there were significant differences on three of the four flexibility measures. There was also no significant difference in the Borg Scale ratings. The second set of comparisons was for measures of processing speed, for which descriptive and inferential statistics are given in Table 4. The effect of group was significant, Wilk's Λ = .21, F(8, 21) = 9.75, p < .001, η² = .788. Follow-up tests showed that improvement for all of these measures was significantly greater in the training group than in the control group. The third set of comparisons was for measures of visuospatial function, for which descriptive and inferential statistics are given in Table 4. The difference between the treatment and control groups was not significant, Wilk's expected a range of practice-related improvements on cognition as previously found in programs of physical activity. In fact, the results demonstrated significant benefits of exergame training on executive control and processing speed tasks from before to after training. Out of six measures of executive functions, we found significant transfer of exergame training on all measures (η² = 0.80). Out of eight measures of processing speed, all measures showed significant improvement (η² = 0.79). This large beneficial effect of training on cognition is in line with findings of many empirical studies on aerobic exercise (e.g., [START_REF] Dustman | Aerobic exercise training and improved neurophysiological function of older adults[END_REF][START_REF] Hawkins | Aging, exercise and attention[END_REF][START_REF] Kramer | Ageing, fitness and neurocognitive function[END_REF]. The results are also consistent with the meta-analytic review of [START_REF] Colcombe | Fitness effects on the cognitive function of older adults: A meta-analytic study[END_REF] which indicated a large effect of physical exercise on executive function tasks (ES = 0.68), which it has been argued are particularly sensitive to the effects of aging [START_REF] West | An application of prefrontal cortex function theory to cognitive aging[END_REF]. They also found positive but somewhat smaller effects of physical activity on processing speed tasks (ES = 0.27). Dustman andcollaborators (1984, 1992) compared the cognitive benefits in older adults among several groups who had followed different training regimens (two of which were aerobic exercise and sedentary videogame playing). The aerobic exercise training showed more transfer of training to executive control and processing speed tasks than did videogame training. They hypothesized that the important difference between sedentary videogame playing and aerobic fitness training may be the improvement in oxygen transport and utilization that results from aerobic fitness. Dustman andcollaborators (1984, 1992) suggested that the increased availability of oxygen for cerebral metabolic activity may be responsible for the improved neurocognitive performance that occurs with fitness training.

Consistent with this hypothesis, our results showed significant effects of training on physical status, and more particularly on cardio-respiratory fitness (e.g., 6MWT). Furthermore, the mean heart rate measured during exergame playing was 102.5±7.9 beats/min, which corresponded to 41.5±9.48 % of the estimated heart rate reserve (HRR). This level of HRR is within the American College of Sports Medicine (ACSM, 2006) recommended "moderate" intensity range of 40-59 % HRR (e.g., [START_REF] Howley | Type of activity: Resistance, aerobic and leisure versus occupational physical activity[END_REF]. Therefore, we speculate that the improvements in cognitive performance with exergame training are in part due to the gains in cardiovascular fitness achieved through regular physical activity, which increased the ability of the heart to deliver oxygen to working muscle and which is indicative of an increase in cardiovascular fitness. So, in this view our results generated positive benefits on cognition in the same manner as physical activity programs. However, one limitation of this interpretation is that we are simply comparing our results with the existing empirical literature rather than including a conventional treatment group in our study which included only physical activity and not exergames. It would be necessary to carry out another intervention study that included a physical activity training group in order to determine how much of the exergame benefits are due to the physical activity.

Although the exergame play engenders a significant increase of energy expenditure (e.g., [START_REF] Graves | The physiological cost and enjoyment of Wii Fit in adolescents, young adults, and older adults[END_REF], a recent study on the cardiovascular and metabolic responses to Wii Fit videogame playing found differences among the Wii games in the HRR response [START_REF] Guderian | The cardiovascular and metabolic responses to Wii Fit video game playing in middle-aged and older adults[END_REF]. Moreover, although for many of our participants HRR response fell within the ACSM recommended "moderate" intensity range, it is also true that for some participants HRR response were below that level. Thus the exercise intensity of Wii exergame playing may not be sufficient to explain the improvements on executive control and processing speed tasks. We speculate that some other aspects of the activity may also account for portions of the improvements we observed. Indeed, the intrinsic characteristics of exergames, such as the motivation and arousal, task difficulty, or feedback (Green & Bavelier, 2008), may well be partly responsible for cognitive improvements as we will discuss below.

The positive benefits on executive control and processing speed performance that we have found with exergames training are also consistent with benefits previously reported with sedentary videogame training. Consistent with the results of [START_REF] Basak | Can training in a real-time strategy videogame attenuate cognitive decline in adults?[END_REF], in which training on a strategy-based game was found to improve executive function, we found evidence for transfer on executive control tasks. Our results also showed a significant transfer of training to processing speed tasks. Other studies using sedentary videogames have reported a robust benefit specifically on psychomotor speed, especially reaction time (e.g., [START_REF] Clark | The effects of videogame playing on the response selection processing of elderly adults[END_REF][START_REF] Drew | Video games: Utilization of a novel strategy to improve perceptual motor skills and cognitive functioning in the non-institutionalized elderly[END_REF][START_REF] Dustman | The effects of videogame playing on neuropsychological performance of elderly individuals[END_REF][START_REF] Goldstein | Videogames and the elderly[END_REF]. Our participants showed improvement not only for measures of psychomotor speed (e.g., tapping) but also for measures of perceptual speed (e.g., cancellation). Perceptual speed is the ability to rapidly and accurately search, compare, and identify elements presented side by side or separated in the visual field. To our knowledge, this is the first time that a positive effect on perceptual speed has been shown with videogame training in older adults.

Moreover, we speculate that the wider transfer of exergame training that we observed may also be due to other aspects of this training in addition to physical activity or videogame play. Our complex training regimen embodied a combination of aspects including the variability of the tasks and the interactions with another player during the training sessions.

The rich environment involved alternation among a wide range of motivating tasks that required several different modes of interaction and varying task difficulty. This training context required the player to alternate between tasks that varied in the priority placed on rapidity (such as the soccer headers game), accuracy (such as the bowling game), strategy (such as the marble game), cognitive judgment (such as the trampoline game) and more global combinations (such as the tennis game). This highly variable environment also engendered physical adjustment to the required activity, either using only the top part of the body, only the lower part of the body, or the whole body. The natural attractiveness of the activities and the motivation of individual feedback are other factors that could have aided in learning a new skill or improving a developing one (e.g., [START_REF] Herzog | The role of feedback in learning a vernier discrimination task[END_REF]. An important aspect of what subjects appear to have learned from this training was the ability to distribute their skills among multiple tasks with different processing priorities, and consequently develop the accommodation of their skills to different tasks.

Finally, there was no transfer of training on visuospatial measures. Our results are consistent with those of [START_REF] Basak | Can training in a real-time strategy videogame attenuate cognitive decline in adults?[END_REF], who also observed no significant training transfer in older adults on visuospatial tasks with a sedentary strategy game. This absence of transfer could be dependent on the specific types of video games used. Indeed, positive benefits have only been reported with video games that involve "action" even though they are sedentary, such as shooting galleries [START_REF] Green | Action video games modify visual selective attention[END_REF], 2006). Games such as this share a set of qualitative features that may be important for transfer to visuospatial tasks, including extraordinary finger speed and a high degree of perceptual, cognitive, and motor load in the service of an accurate motor plan, unpredictability, and an emphasis on peripheral processing [START_REF] Green | Perceptual learning during action video game playing[END_REF]. The games that we used in our study did not share these specific characteristics.

One limitation of our study was that we did not have a comparison group that played sedentary videogames or one that engaged only in a social participation or interpersonal interaction program. Hence, we cannot distinguish conclusively between the physical activity component of the training regimen, the cognitive content of the training regimen, and the social stimulation of the regimen as the possible sources of improvement. Many studies have showed that social interaction may longitudinally protect against cognitive decline (e.g., [START_REF] Glei | Participating in social activities helps preserve cognitive function: an analysis of a longitudinal, population-based study of the elderly[END_REF]Zunzunegri, Alvarado, Del Ser, & Otero, 2003). However, there is no evidence that social interaction produces immediate improvements in cognition. Future research should assess whether the exergames provided an additive effect of physical activity and sedentary videogaming, or whether benefits of exergame training reflected an interactive effect of cognitive and physical demand. Clearly, this important direction might permit us to understand more accurately the real potential of this new mode of physical activity.

In summary, our study suggests that exergame training, combining cognitive and physical demands in an intrinsically attractive activity, might be an effective way to promote physical and cognitive improvements among older adults. Indeed, one current health issue is to improve the level of physical activity of elderly adults, particularly with sedentary lifestyle (American College of Sports Medicine, 2006). Thus, exergames could be an entree to vigorous physical exercise and a complement to the conventional physical activity for sedentary older adults. It was encouraging to observe, with physically-simulated sport games, transfer benefits to cognitive and physical skills that are directly involved in functional abilities needed by older adults in everyday living (e.g., [START_REF] Tomaszewski | Longitudinal Changes in Memory and Executive Functioning are Associated with Longitudinal Change in Instrumental Activities of Daily Living in older adults[END_REF]. Indeed, previous studies have demonstrated relationships between neuropsychological performance and everyday function in older adult (e.g., [START_REF] Royall | Declining executive control in normal aging predicts change in functional status: the Freedom House Study[END_REF]. Several attributes of exergames make them promising for widespread adoption. First, exergame play can be home based, mitigating against environmental barriers to exercise. Second, the games allow for choice among activities, which could lead to sustained play and foster autonomy, and thus result in a personalized intervention for people with diverse physical abilities.

Finally, the games are fun and affordable. Footnote 1 Chair stand: Number of full stands that can be completed in 30 seconds with arms folded across chest. Arm curl: Number of bicep curls that can be completed in 30 seconds holding a hand weight of 5 lbs (2.27 kg) for women; 8 lbs (3.63 kg) for men. 6-Minute Walking Test: The number of meters walked in 6 min, the maximum heart rate, the mean heart rate, and the rated exertion using the Borg scale were recorded. Chair sit and reach: From a sitting position at front of chair, with leg extended and hands reaching toward toes, the number of inches (cm) (+ or -) between extended fingers and tip of toe. Back scratch: With one hand reaching over the shoulder and one up the middle of the back, the number of inches (cm) between extended middle fingers (+ or -). 8 foot up and go test: Number of seconds required to get up from a seated position, walk 8 feet (2.44 m), turn, and return to seated position. 2 The Letter Sets test and the Matrix Reasoning test are classified as tests of inductive reasoning (e.g., [START_REF] Ackerman | A correlational analysis of skill specificity: Learning, abilities, and individual differences[END_REF]. Researchers have demonstrated that inductive reasoning is a higher executive function important for everyday functioning and sensitive to age-related deficits (e.g., Blaskewicz Boron, Turiano, Willis, & Schaie, 2007). [START_REF] Cohen | Statistical power analysis for the behavioral science[END_REF]. For heart rate, chair stand and arm curl, a positive mean corresponds to an improvement between pre-and post-test. For 8 foot Up and Go, and back scratch, a negative mean corresponds to an improvement between pre-and post-test. All p values smaller than p = .05 remain significant after Bonferroni correction. [START_REF] Cohen | Statistical power analysis for the behavioral science[END_REF]. For timed tests, a negative mean corresponds to an improvement between pre-and post-test. For scored tests (indicated by Number), a positive mean corresponds to an improvement between pre-and post-test. All p values smaller than p = .05 remain significant after Bonferroni correction.

  scale (range 0 to 10, with 0 = complete rest and 10 = extremely strong) were recorded. The chair sit-and-reach test evaluates lower body flexibility and the back scratch test measurement upper body flexibility. The 8-foot up-and-go test evaluates agility and balance. Rikli and Jones (2001) give a complete description of these tests 1 . Heart rate (HR) was monitored using a standard chest lead connected to a digital pulse transmitter (SUUNTO T6 -software SUUNTO Training Manager, version 2.3.0.15). Several recordings were made during the study: at the outset of the study, during the 6MWT during the pretraining and post-training sessions (walk and rest), and for the training group, during the second, twelfth, and twenty-second training sessions. The resting heart rate (RHR) was measured for 15 minutes with participants in the supine position at the first assessment session. The purpose was to be able to quantify the intensity of the physical exercise throughout the course of the program through the calculation of the proportion of the heart rate reserve according to the method of

  figures(1971) introduced by[START_REF] Vandenberg | Mental rotations, a group test of three dimensional spatial visualization[END_REF] who used the original figures to

  consisting of a page of randomly-generated uppercase English letters. All letters occurred with equal probability and participants were instructed to place a line through each occurrence of a target letter (A) in 60 seconds. The score was the number correctly marked.NumberComparison test. This is another perceptual speed test[START_REF] Ackerman | Cognitive, perceptual speed, and psychomotor determinants of individual differences during skill acquisition[END_REF] consisting of two 50-item columns of digits. Participants are instructed to place a check mark between adjacent numbers that match exactly. The score is the number of correct items in 90 seconds.Reaction Time test. Speed of response in milliseconds was measured for simple reaction time (SRT; a single stimulus) and choice reaction time (CRT; four stimuli). Both SRT and CRT can be decomposed into decision time (DT; the time to lift a finger from a start button to begin movement toward to a target button) and Movement Time (MT; the time from lifting the finger until the target button is pressed). Instructions and stimuli were presented with a Pentium 4 PC, with standard keyboards and E-Prime software which recorded accuracy and response time (version 1.1 beta 1.0, Schneider,Eschman, & Zuccolotto, 2002). The stimulus was a red circle. For SRT the red circle appeared only at the left corner of the screen and the participant responded by pressing the spacebar as quickly as possible. For CRT the red circle could appear at one of four positions along an imaginary circular arc. The participant responded by pressing the a key on the numeric keypad corresponding to the position of the red circle-1 for lower left, 7 for upper left, 9 for upper right, and 3 for lower right. Performance was measured as the mean SRT and CRT in milliseconds on a block of 12 trials.

  The second step in the analysis was to characterize the participants in the training group and the nature and effect of their training. The number of completed sessions for the 15 participants ranged from 20 to 24 (M = 23.40). Overall adherence was 97.50%, with 351 out of a possible 360 sessions (15 participants for 12 weeks with 2 sessions per week) completed by participants. The final questionnaire indicated that the exergame training was manageable for older persons (80% agreed), and seemed comparable to other physical activity (80% of results ranged between very much and relatively). All participants reported that they would like to continue with exergame activity, however only 40% contemplated acquiring a game console. Finally, 67% of participants thought that their body knowledge improved with training program, and 47% were considering beginning a program of physical activity.Participants showed significant improvement in performance across training sessions on all four of the exergames: for the balance task, F(23, 207) = 10.79, p < .01, η² = .55, for the cognitive task, F(23, 207) = 14.25, p < .01, η² = .61, for the energy task, F(23, 138) = 2.66, p < .01, η² = .31, and for the global task, F(23, 230) = 6.70, p < .01, η² = .40. Follow up tests using Tukey's HSD, showed significant improvement over the first session by the sixth session in the balance task (Ski Slalom), by the seventh session in the cognitive task (Trampoline), by the tenth session in the global task (Tennis Return of Serve), and by the twenty-third session in the energy task (Hula Hoop). We note that only six of the participants continued the energy task until the final training session. In addition, heart rate was measured during the second, twelfth, and twenty-second training sessions. There were no significant changes across these three sessions in mean heart rate, F(2, 26) = 0.78, p = .47, in maximum heart rate, F(2, 26) = 1.97, p = .16, or in proportion of heart rate reserve achieved, F(2, 26) = 2.00, p = .16.

  tasks (Trail Making test, Stroop Color Word Interference test, Letter Sets test, Matrix Reasoning test 2 , Digit Symbol Substitution test), visuospatial tasks (Spatial Span test, Directional Headings test, Mental Rotation test) and processing speed tasks subdivided into two categories, perceptual speed (Cancellation test and Number Comparison test) and psychomotor speed (the Reaction Time test and Plate Tapping test). All these tasks are described below.

	Executive Control Tasks
	Trail Making test. The Trail Making test

Table 1

 1 Means of Demographic, Health, Exercise, and Subjective Well-Being Variables for Control

			and Training Groups
		Control	Training
	Variables	M	SD	M	SD	t	p
	Age (years)	73.47	3.00	73.47	4.10	0.00	0.81
	Self-rated health	3.67	0.62	3.73	0.59	0.30	0.76
	Years of education	11.40	2.22	11.20	1.78	-0.27	0.78
	Body Mass Index (kg/m 2 )	27.62	5.89	27.40	4.46	-0.18	0.90
	MMSE	29.27	0.88	28.67	1.17	-1.58	0.12
	GDS	5.93	2.66	6.00	3.48	0.06	0.95
	MAQ (hr/week)	0.60	0.58	0.79	0.59	0.88	0.38
	Note. M = Mean. SD = Standard Deviation. MMSE = Mini Mental State Examination. GDS = Geriatric Depression Scale.
		MAQ = Modifiable Activity Questionnaire

Table 2

 2 Comparison on Pre-test Measures by Condition

		Control	Training
		M	SD	M	SD	t	p
	Resting Heart Rate (bpm)	63.60	8.08	64.57	8.33	-0.32	0.75
	Max Heart Rate 6-min Walk (bpm)	107.87	16.02	116.57	17.45	-1.40	0.17
	Mean Heart Rate 6-min Walk (bpm)	100.27	15.10	106.86	11.63	-1.31	0.20
	Chair stands (Number)	14.27	3.67	12.93	2.66	1.14	0.26
	Arm curls (Number)	16.80	2.57	16.53	3.25	0.25	0.80
	6-min Walk (Meters covered)	429.84	61.58	411.17	84.69	0.69	0.50
	8-foot Up-and-Go (sec)	7.12	1.64	7.42	1.38	-0.56	0.58
	Back Scratch "lower right" (cm)	0.87	6.17	3.67	8.17	-1.06	0.30
	Back Scratch "lower left" (cm)	0.90	6.74	3.40	8.73	-0.88	0.39
	Back Scratch "upper right" (cm)	5.57	9.08	5.63	8.29	-0.02	0.98
	Back Scratch "upper left" (cm)	14.43	13.51	13.03	10.85	0.31	0.76
	Perceived Effort 6-min Walk	2.87	1.06	4.00	1.47	-2.40	0.02

Note. M = Mean. SD = Standard Deviation.

Table 3

 3 Comparison of Pretest-Posttest Change Scores on Physical Measures for Training and Control

			Groups
		Control	Training
		M	SD	M	SD	t	p	η²
	Physical Measures							0.693
	Max Heart Rate 6-min Walk (bpm)	-4.07	10.15	10.50	15.92	-2.96 < 0.01 0.227
	Mean Heart Rate 6-min Walk (bpm) -3.80	11.62	7.43	13.52	-2.40	0.01 0.169
	Chair Stands (Number)	-1.07	1.94	2.73	2.28	-4.91 < 0.01 0.528
	Arm Curls (Number)	0.00	2.73	3.00	2.70	-3.02 < 0.01 0.262
	6-min Walk (Meters covered)	3.07	26.54	58.05	40.45	-4.40 < 0.01 0.408
	8-foot Up and Go (sec)	0.48	1.05	-0.94	0.62	4.53 < 0.01 0.424
	Back Scratch "lower right" (cm)	2.00	5.80	-2.78	6.20	2.18	0.02 0.130
	Back Scratch "lower left" (cm)	2.10	6.88	-2.22	6.27	1.80	0.04 0.107
	Back Scratch "upper right" (cm)	-3.85	10.35	-0.50	5.33	-1.12	0.14 0.051
	Back Scratch "upper left" (cm)	-9.40	18.04	0.25	3.90	-2.03	0.03 0.017
	Perceived Exertion (Borg Scale)	0.67	1.11	0.64	1.82	.043	0.48 0.001

Note. M = Mean. SD = Standard Deviation. η² = effect size

Table 4

 4 Comparison of Pretest-Posttest Change Scores on Executive Function, Processing Speed, and Visuospatial Measures for Training and Control Groups Note. M = Mean. SD = Standard Deviation. η² = effect size

	Control	Training

Λ = .77, F(4, 25) = 1.87, p = n.s, η² = .230. The fourth set of comparisons was for measures of executive function, for which descriptive and inferential statistics are also given in Table 4.

Here the improvement was significantly greater in the treatment than in the control group, Wilk's Λ = .19, F(6, 23) = 15.79, p < .001, η² = .805, and follow-up tests showed that this was true for all of the measures.

Discussion

The purpose of the present study was to determine the potential of training based on physically-simulated sport play as a mode of activity that could have cognitive benefits for older adults. The training program was modeled on programs of physical activity and programs of sedentary videogame play that had previously shown cognitive benefits.

The first hypothesis was that exergame training would produce gains in performance on the Wii sports tasks themselves. We found that practice did result in improved performance on the Wii tasks. Participants showed significant and substantial gains in performance on the four performance tasks which challenged a variety of abilities over the course of 24 hours of practice across 12 weeks. These improvements showed that this inactive population could benefit from the stimulation of exergames. This finding is strengthened by both the high levels of exercise adherence (97.50%) and the questionnaire reports that participants appreciated and would like to continue exergame activity. [START_REF] Graves | The physiological cost and enjoyment of Wii Fit in adolescents, young adults, and older adults[END_REF] showed that Wii tasks generated more enjoyment than sedentary videogame or treadmill exercise in older adults. Our results underscore the potential of exergames in terms of accessibility and intrinsic attractiveness for older adults. Thus interactive physical-activity videogames could be an enjoyable alternative to physical activity (e.g., [START_REF] Hughes | Bestpractice physical activity programs for older adults: Findings from the national impact study[END_REF][START_REF] Schutzer | Barriers and motivations to exercise in older adults[END_REF].

The second hypothesis of this study was that interactive physical-activity videogame training was a mode of activity that could have cognitive benefits for older adults. First, we Authors' Footnote Pauline Maillot, Alexandra Perrot, CIAMS EA 4532, Université Paris-Sud Alan Hartley, Scripps College, Claremont, California.

Correspondence concerning this article should be addressed to Pauline Maillot, UFR STAPS -Bât 335, Université Paris-Sud, 91405 Orsay Cedex, France, pauline.maillot@u-psud.fr.