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Hearing loss

Hearing loss is a partial or total inability to hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to acquire spoken language, and in adults it can create difficulties with social interaction and at work. Hearing loss can be temporary or permanent. Hearing loss related to age usually affects both ears and is due to cochlear hair cell loss. In some people, particularly older people, hearing loss can result in loneliness.

Hearing loss may be caused by a number of factors, including: genetics, ageing, exposure to noise, some infections, birth complications, trauma to the ear, and certain medications or toxins. A common condition that results in hearing loss is chronic ear infections. Certain infections during pregnancy, such as cytomegalovirus, syphilis and rubella, may also cause hearing loss in the child. Hearing loss is diagnosed when hearing testing finds that a person is unable to hear 25 decibels in at least one ear. Testing for poor hearing is recommended for all newborns. Hearing loss can be categorized as mild (25 to 40 dB), moderate (41 to 55 dB), moderate-severe (56 to 70 dB), severe (71 to 90 dB), or profound (greater than 90 dB). There are three main types of hearing loss: conductive hearing loss, sensorineural hearing loss, and mixed hearing loss.

About half of hearing loss globally is preventable through public health measures. Such practices include immunization, proper care around pregnancy, avoiding loud noise, and avoiding certain medications. The World Health Organization recommends that young people limit exposure to loud sounds and the use of personal audio players to an hour a day in an effort to limit exposure to noise. Early identification and support are particularly important in children. For many, hearing aids, sign language, cochlear implants and subtitles are useful. Lip reading is another useful skill some develop. Access to hearing aids, however, is limited in many areas of the world.

As of 2013 hearing loss affects about 1.1 billion people to some degree. It causes disability in about 466 million people (5% of the global population), and moderate to severe disability in 124 million people. Of those with moderate to severe disability 108 million live in low and middle income countries. Of those with hearing loss, it began during childhood for 65 million. Those who use sign language and are members of Deaf culture may see themselves as having a difference rather than a disability. Many members of Deaf culture oppose attempts to cure deafness  and some within this community view cochlear implants with concern as they have the potential to eliminate their culture.

Definition

 * Hearing loss is defined as diminished acuity to sounds which would otherwise be heard normally. The terms hearing impaired or hard of hearing are usually reserved for people who have relative inability to hear sound in the speech frequencies. Hearing loss occurs when sound waves enter the ears and damage the sensitive tissues The severity of hearing loss is categorized according to the increase in intensity of sound above the usual level required for the listener to detect it.
 * Deafness is defined as a degree of loss such that a person is unable to understand speech, even in the presence of amplification. In profound deafness, even the highest intensity sounds produced by an audiometer (an instrument used to measure hearing by producing pure tone sounds through a range of frequencies) may not be detected. In total deafness, no sounds at all, regardless of amplification or method of production, can be heard.
 * Speech perception is another aspect of hearing which involves the perceived clarity of a word rather than the intensity of sound made by the word. In humans, this is usually measured with speech discrimination tests, which measure not only the ability to detect sound, but also the ability to understand speech. There are very rare types of hearing loss that affect speech discrimination alone. One example is auditory neuropathy, a variety of hearing loss in which the outer hair cells of the cochlea are intact and functioning, but sound information is not faithfully transmitted by the auditory nerve to the brain.

Use of the terms "hearing impaired", "deaf-mute", or "deaf and dumb" to describe deaf and hard of hearing people is discouraged by many in the deaf community as well as advocacy organizations, as they are offensive to many deaf and hard of hearing people.

Hearing standards
Human hearing extends in frequency from 20 to 20,000 Hz, and in intensity from 0 dB to 120 dB HL or more. 0 dB does not represent absence of sound, but rather the softest sound an average unimpaired human ear can hear; some people can hear down to −5 or even −10 dB. Sound is generally uncomfortably loud above 90 dB and 115 dB represents the threshold of pain. The ear does not hear all frequencies equally well: hearing sensitivity peaks around 3,000 Hz. There are many qualities of human hearing besides frequency range and intensity that cannot easily be measured quantitatively. However, for many practical purposes, normal hearing is defined by a frequency versus intensity graph, or audiogram, charting sensitivity thresholds of hearing at defined frequencies. Because of the cumulative impact of age and exposure to noise and other acoustic insults, 'typical' hearing may not be normal.

Signs and symptoms

 * difficulty using the telephone
 * loss of sound localization
 * difficulty understanding speech, especially of children and women whose voices are of a higher frequency.
 * difficulty understanding speech in the presence of background noise (cocktail party effect)
 * sounds or speech sounding dull, muffled or attenuated
 * need for increased volume on television, radio, music and other audio sources

Hearing loss is sensory, but may have accompanying symptoms:
 * pain or pressure in the ears
 * a blocked feeling

There may also be accompanying secondary symptoms:
 * hyperacusis, heightened sensitivity with accompanying auditory pain to certain intensities and frequencies of sound, sometimes defined as "auditory recruitment"
 * tinnitus, ringing, buzzing, hissing or other sounds in the ear when no external sound is present
 * vertigo and disequilibrium
 * tympanophonia, also known as autophonia, abnormal hearing of one's own voice and respiratory sounds, usually as a result of a patulous (a constantly open) eustachian tube or dehiscent superior semicircular canals
 * disturbances of facial movement (indicating a possible tumour or stroke) or in persons with Bell's palsy

Complications
Hearing loss is associated with Alzheimer's disease and dementia. The risk increases with the hearing loss degree. There are several hypotheses including cognitive resources being redistributed to hearing and social isolation from hearing loss having a negative effect. According to preliminary data, hearing aid usage can slow down the decline in cognitive functions.

Hearing loss is responsible for causing thalamocortical dysrthymia in the brain which is a cause for several neurological disorders including tinnitus and visual snow syndrome.

Cognitive decline
Hearing loss is an increasing concern especially in aging populations. The prevalence of hearing loss increases about two-fold for each decade increase in age after age 40. While the secular trend might decrease individual level risk of developing hearing loss, the prevalence of hearing loss is expected to rise due to the aging population in the US. Another concern about aging process is cognitive decline, which may progress to mild cognitive impairment and eventually dementia. The association between hearing loss and cognitive decline has been studied in various research settings. Despite the variability in study design and protocols, the majority of these studies have found consistent association between age-related hearing loss and cognitive decline, cognitive impairment, and dementia. The association between age-related hearing loss and Alzheimer's disease was found to be nonsignificant, and this finding supports the hypothesis that hearing loss is associated with dementia independent of Alzheimer pathology. There are several hypotheses about the underlying causal mechanism for age-related hearing loss and cognitive decline. One hypothesis is that this association can be explained by common etiology or shared neurobiological pathology with decline in other physiological system. Another possible cognitive mechanism emphasize on individual's cognitive load. As people developing hearing loss in the process of aging, the cognitive load demanded by auditory perception increases, which may lead to change in brain structure and eventually to dementia. One other hypothesis suggests that the association between hearing loss and cognitive decline is mediated through various psychosocial factors, such as decrease in social contact and increase in social isolation. Findings on the association between hearing loss and dementia have significant public health implication, since about 9% of dementia cases are associated with hearing loss.

Falls
Falls have important health implications, especially for an aging population where they can lead to significant morbidity and mortality. Elderly people are particularly vulnerable to the consequences of injuries caused by falls, since older individuals typically have greater bone fragility and poorer protective reflexes. Fall-related injury can also lead to burdens on the financial and health care systems. In literature, age-related hearing loss is found to be significantly associated with incident falls. There is also a potential dose-response relationship between hearing loss and falls—greater severity of hearing loss is associated with increased difficulties in postural control and increased prevalence of falls. The underlying causal link between the association of hearing loss and falls is yet to be elucidated. There are several hypotheses that indicate that there may be a common process between decline in auditory system and increase in incident falls, driven by physiological, cognitive, and behavioral factors. This evidence suggests that treating hearing loss has potential to increase health-related quality of life in older adults.

Depression
Depression is one of the leading causes of morbidity and mortality worldwide. In older adults, the suicide rate is higher than it is for younger adults, and more suicide cases are attributable to depression. Different studies have been done to investigate potential risk factors that can give rise to depression in later life. Some chronic diseases are found to be significantly associated with risk of developing depression, such as coronary heart disease, pulmonary disease, vision loss and hearing loss. Hearing loss can attribute to decrease in health-related quality of life, increase in social isolation and decline in social engagement, which are all risk factors for increased risk of developing depression symptoms.

Spoken language ability
Post-lingual deafness is hearing loss that is sustained after the acquisition of language, which can occur due to disease, trauma, or as a side-effect of a medicine. Typically, hearing loss is gradual and often detected by family and friends of affected individuals long before the patients themselves will acknowledge the disability. Post-lingual deafness is far more common than pre-lingual deafness. Those who lose their hearing later in life, such as in late adolescence or adulthood, face their own challenges, living with the adaptations that allow them to live independently.

Prelingual deafness is profound hearing loss that is sustained before the acquisition of language, which can occur due to a congenital condition or through hearing loss before birth or in early infancy. Prelingual deafness impairs an individual's ability to acquire a spoken language in children, but deaf children can acquire spoken language through support from cochlear implants (sometimes combined with hearing aids). Non-signing (hearing) parents of deaf babies (90–95% of cases) usually go with oral approach without the support of sign language, as these families lack previous experience with sign language and cannot competently provide it to their children without learning it themselves. This may in some cases (late implantation or not sufficient benefit from cochlear implants) bring the risk of language deprivation for the deaf baby because the deaf baby would not have a sign language if the child is unable to acquire spoken language successfully. The 5–10% of cases of deaf babies born into signing families have the potential of age-appropriate development of language due to early exposure to a sign language by sign-competent parents, thus they have the potential to meet language milestones, in sign language in lieu of spoken language.

Causes
Hearing loss has multiple causes, including ageing, genetics, perinatal problems and acquired causes like noise and disease. For some kinds of hearing loss the cause may be classified as of unknown cause.

There is a progressive loss of ability to hear high frequencies with aging known as presbycusis. For men, this can start as early as 25 and women at 30. Although genetically variable, it is a normal concomitant of ageing and is distinct from hearing losses caused by noise exposure, toxins or disease agents. Common conditions that can increase the risk of hearing loss in elderly people are high blood pressure, diabetes (hearing loss in diabetes), or the use of certain medications harmful to the ear. While everyone loses hearing with age, the amount and type of hearing loss is variable.

Noise-induced hearing loss (NIHL), also known as acoustic trauma, typically manifests as elevated hearing thresholds (i.e. less sensitivity or muting). Noise exposure is the cause of approximately half of all cases of hearing loss, causing some degree of problems in 5% of the population globally. The majority of hearing loss is not due to age, but due to noise exposure. Various governmental, industry and standards organizations set noise standards. Many people are unaware of the presence of environmental sound at damaging levels, or of the level at which sound becomes harmful. Common sources of damaging noise levels include car stereos, children's toys, motor vehicles, crowds, lawn and maintenance equipment, power tools, gun use, musical instruments, and even hair dryers. Noise damage is cumulative; all sources of damage must be considered to assess risk. In the US, 12.5% of children aged 6–19 years have permanent hearing damage from excessive noise exposure. The World Health Organization estimates that half of those between 12 and 35 are at risk from using personal audio devices that are too loud. Hearing loss in adolescents may be caused by loud noise from toys, music by headphones, and concerts or events.

Hearing loss can be inherited. Around 75–80% of all these cases are inherited by recessive genes, 20–25% are inherited by dominant genes, 1–2% are inherited by X-linked patterns, and fewer than 1% are inherited by mitochondrial inheritance. Syndromic deafness occurs when there are other signs or medical problems aside from deafness in an individual, such as Usher syndrome, Stickler syndrome, Waardenburg syndrome, Alport's syndrome, and neurofibromatosis type 2. Nonsyndromic deafness occurs when there are no other signs or medical problems associated with the deafness in an individual.

Fetal alcohol spectrum disorders are reported to cause hearing loss in up to 64% of infants born to alcoholic mothers, from the ototoxic effect on the developing fetus plus malnutrition during pregnancy from the excess alcohol intake. Premature birth can be associated with sensorineural hearing loss because of an increased risk of hypoxia, hyperbilirubinaemia, ototoxic medication and infection as well as noise exposure in the neonatal units. Also, hearing loss in premature babies is often discovered far later than a similar hearing loss would be in a full-term baby because normally babies are given a hearing test within 48 hours of birth, but doctors must wait until the premature baby is medically stable before testing hearing, which can be months after birth. The risk of hearing loss is greatest for those weighing less than 1500 g at birth.

Disorders responsible for hearing loss include auditory neuropathy, Down syndrome, Charcot–Marie–Tooth disease variant 1E, autoimmune disease, multiple sclerosis, meningitis, cholesteatoma, otosclerosis, perilymph fistula, Ménière's disease, recurring ear infections, strokes, superior semicircular canal dehiscence, Pierre Robin, Treacher-Collins, Usher Syndrome, Pendred Syndrome, and Turner syndrome, syphilis, vestibular schwannoma, and viral infections such as measles, mumps, congenital rubella (also called German measles) syndrome, several varieties of herpes viruses, HIV/AIDS, and West Nile virus.

Some medications may reversibly affect hearing. These medications are considered ototoxic. This includes loop diuretics such as furosemide and bumetanide, non-steroidal anti-inflammatory drugs (NSAIDs) both over-the-counter (aspirin, ibuprofen, naproxen) as well as prescription (celecoxib, diclofenac, etc.), paracetamol, quinine, and macrolide antibiotics. Others may cause permanent hearing loss. The most important group is the aminoglycosides (main member gentamicin) and platinum based chemotherapeutics such as cisplatin and carboplatin.

In addition to medications, hearing loss can also result from specific chemicals in the environment: metals, such as lead; solvents, such as toluene (found in crude oil, gasoline and automobile exhaust, for example); and asphyxiants. Combined with noise, these ototoxic chemicals have an additive effect on a person's hearing loss. Hearing loss due to chemicals starts in the high frequency range and is irreversible. It damages the cochlea with lesions and degrades central portions of the auditory system. For some ototoxic chemical exposures, particularly styrene, the risk of hearing loss can be higher than being exposed to noise alone. The effects is greatest when the combined exposure include impulse noise. A 2018 informational bulletin by the US Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) introduces the issue, provides examples of ototoxic chemicals, lists the industries and occupations at risk and provides prevention information.

There can be damage either to the ear, whether the external or middle ear, to the cochlea, or to the brain centers that process the aural information conveyed by the ears. Damage to the middle ear may include fracture and discontinuity of the ossicular chain. Damage to the inner ear (cochlea) may be caused by temporal bone fracture. People who sustain head injury are especially vulnerable to hearing loss or tinnitus, either temporary or permanent.

Pathophysiology
Sound waves reach the outer ear and are conducted down the ear canal to the eardrum, causing it to vibrate. The vibrations are transferred by the 3 tiny ear bones of the middle ear to the fluid in the inner ear. The fluid moves hair cells (stereocilia), and their movement generates nerve impulses which are then taken to the brain by the cochlear nerve. The auditory nerve takes the impulses to the brainstem, which sends the impulses to the midbrain. Finally, the signal goes to the auditory cortex of the temporal lobe to be interpreted as sound.

Hearing loss is most commonly caused by long-term exposure to loud noises, from recreation or from work, that damage the hair cells, which do not grow back on their own.

Older people may lose their hearing from long exposure to noise, changes in the inner ear, changes in the middle ear, or from changes along the nerves from the ear to the brain.

Diagnosis

Identification of a hearing loss is usually conducted by a general practitioner medical doctor, otolaryngologist, certified and licensed audiologist, school or industrial audiometrist, or other audiometric technician. Diagnosis of the cause of a hearing loss is carried out by a specialist physician (audiovestibular physician) or otorhinolaryngologist.

Hearing loss is generally measured by playing generated or recorded sounds, and determining whether the person can hear them. Hearing sensitivity varies according to the frequency of sounds. To take this into account, hearing sensitivity can be measured for a range of frequencies and plotted on an audiogram. Other method for quantifying hearing loss is a hearing test using a mobile application or hearing aid application, which includes a hearing test. Hearing diagnosis using mobile application is similar to the audiometry procedure. Audiograms, obtained using mobile applications, can be used to adjust hearing aid applications. Another method for quantifying hearing loss is a speech-in-noise test. which gives an indication of how well one can understand speech in a noisy environment. Otoacoustic emissions test is an objective hearing test that may be administered to toddlers and children too young to cooperate in a conventional hearing test. Auditory brainstem response testing is an electrophysiological test used to test for hearing deficits caused by pathology within the ear, the cochlear nerve and also within the brainstem.

A case history (usually a written form, with questionnaire) can provide valuable information about the context of the hearing loss, and indicate what kind of diagnostic procedures to employ. Examinations include otoscopy, tympanometry, and differential testing with the Weber, Rinne, Bing and Schwabach tests. In case of infection or inflammation, blood or other body fluids may be submitted for laboratory analysis. MRI and CT scans can be useful to identify the pathology of many causes of hearing loss.

Hearing loss is categorized by severity, type, and configuration. Furthermore, a hearing loss may exist in only one ear (unilateral) or in both ears (bilateral). Hearing loss can be temporary or permanent, sudden or progressive. The severity of a hearing loss is ranked according to ranges of nominal thresholds in which a sound must be so it can be detected by an individual. It is measured in decibels of hearing loss, or dB HL. There are three main types of hearing loss: conductive hearing loss, sensorineural hearing loss, and mixed hearing loss. An additional problem which is increasingly recognised is auditory processing disorder which is not a hearing loss as such but a difficulty perceiving sound. The shape of an audiogram shows the relative configuration of the hearing loss, such as a Carhart notch for otosclerosis, 'noise' notch for noise-induced damage, high frequency rolloff for presbycusis, or a flat audiogram for conductive hearing loss. In conjunction with speech audiometry, it may indicate central auditory processing disorder, or the presence of a schwannoma or other tumor.

People with unilateral hearing loss or single-sided deafness (SSD) have difficulty in hearing conversation on their impaired side, localizing sound, and understanding speech in the presence of background noise. One reason for the hearing problems these patients often experience is due to the head shadow effect.

Idiopathic sudden hearing loss is a condition where a person as an immediate decrease in the sensitivity of their sensorineural hearing that does not have a known cause. This type of loss is usually only on one side (unilateral) and the severity of the loss varies. A common threshold of a "loss of at least 30 dB in three connected frequencies within 72 hours" is sometimes used, however there is no universal definition or international consensus for diagnosing idiopathic sudden hearing loss.

Prevention
It is estimated that half of cases of hearing loss are preventable. About 60% of hearing loss in children under the age of 15 can be avoided. There are a number of effective preventative strategies, including: immunization against rubella to prevent congenital rubella syndrome, immunization against H. influenza and S. pneumoniae to reduce cases of meningitis, and avoiding or protecting against excessive noise exposure. The World Health Organization also recommends immunization against measles, mumps, and meningitis, efforts to prevent premature birth, and avoidance of certain medication as prevention. World Hearing Day is a yearly event to promote actions to prevent hearing damage.

Avoiding exposure to loud noise can help prevent noise-induced hearing loss. 18% of adults exposed to loud noise at work for five years or more report hearing loss in both ears as compared to 5.5% of adults who were not exposed to loud noise at work. Different programs exist for specific populations such as school-age children, adolescents and workers. But the HPD (without individual selection, training and fit testing) does not significantly reduce the risk of hearing loss. The use of antioxidants is being studied for the prevention of noise-induced hearing loss, particularly for scenarios in which noise exposure cannot be reduced, such as during military operations.

Workplace noise regulation
Noise is widely recognized as an occupational hazard. In the United States, the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA) work together to provide standards and enforcement on workplace noise levels. The hierarchy of hazard controls demonstrates the different levels of controls to reduce or eliminate exposure to noise and prevent hearing loss, including engineering controls and personal protective equipment (PPE). Other programs and initiative have been created to prevent hearing loss in the workplace. For example, the Safe-in-Sound Award was created to recognize organizations that can demonstrate results of successful noise control and other interventions. Additionally, the Buy Quiet program was created to encourage employers to purchase quieter machinery and tools. By purchasing less noisy power tools like those found on the NIOSH Power Tools Database and limiting exposure to ototoxic chemicals, great strides can be made in preventing hearing loss.

Companies can also provide personal hearing protector devices tailored to both the worker and type of employment. Some hearing protectors universally block out all noise, and some allow for certain noises to be heard. Workers are more likely to wear hearing protector devices when they are properly fitted.

Often interventions to prevent noise-induced hearing loss have many components. A 2017 Cochrane review found that stricter legislation might reduce noise levels. Providing workers with information on their sound exposure levels was not shown to decrease exposure to noise. Ear protection, if used correctly, can reduce noise to safer levels, but often, providing them is not sufficient to prevent hearing loss. Engineering noise out and other solutions such as proper maintenance of equipment can lead to noise reduction, but further field studies on resulting noise exposures following such interventions are needed. Other possible solutions include improved enforcement of existing legislation and better implementation of well-designed prevention programmes, which have not yet been proven conclusively to be effective. The conclusion of the Cochrane Review was that further research could modify what is now regarding the effectiveness of the evaluated interventions.

The Institute for Occupational Safety and Health of the German Social Accident Insurance has created a hearing impairment calculator based on the ISO 1999 model for studying threshold shift in relatively homogeneous groups of people, such as workers with the same type of job. The ISO 1999 model estimates how much hearing impairment in a group can be ascribed to age and noise exposure. The result is calculated via an algebraic equation that uses the A-weighted sound exposure level, how many years the people were exposed to this noise, how old the people are, and their sex. The model's estimations are only useful for people without hearing loss due to non-job related exposure and can be used for prevention activities.

Screening
The United States Preventive Services Task Force recommends neonatal hearing screening for all newborns, as the first three years of life are believed to be the most important for language development. Universal neonatal hearing screenings have now been widely implemented across the U.S., with rates of newborn screening increasing from less than 3% in the early 1990s to 98% in 2009. Newborns whose screening reveals a high index of suspicion of hearing loss are referred for additional diagnostic testing with the goal of providing early intervention and access to language.

The American Academy of Pediatrics advises that children should have their hearing tested several times throughout their schooling: While the American College of Physicians indicated that there is not enough evidence to determine the utility of screening in adults over 50 years old who do not have any symptoms, the American Language, Speech Pathology and Hearing Association recommends that adults should be screened at least every decade through age 50 and at three-year intervals thereafter, to minimize the detrimental effects of the untreated condition on quality of life. For the same reason, the US Office of Disease Prevention and Health Promotion included as one of Healthy People 2020 objectives: to increase the proportion of persons who have had a hearing examination.
 * When they enter school
 * At ages 6, 8, and 10
 * At least once during middle school
 * At least once during high school

Management
Management depends on the specific cause if known as well as the extent, type and configuration of the hearing loss. Sudden hearing loss due to an underlying nerve problem may be treated with corticosteroids.

Most hearing loss, that result from age and noise, is progressive and irreversible, and there are currently no approved or recommended treatments. A few specific kinds of hearing loss are amenable to surgical treatment. In other cases, treatment is addressed to underlying pathologies, but any hearing loss incurred may be permanent. Some management options include hearing aids, cochlear implants, middle ear implants, assistive technology, and closed captioning; in movie theaters, a Hearing Impaired (HI) audio track may be available via headphones to better hear dialog.

This choice depends on the level of hearing loss, type of hearing loss, and personal preference. Hearing aid applications are one of the options for hearing loss management. For people with bilateral hearing loss, it is not clear if bilateral hearing aids (hearing aids in both ears) are better than a unilateral hearing aid (hearing aid in one ear).

Idiopathic sudden hearing loss
For people with idiopathic sudden hearing loss, different treatment approaches have been suggested that are usually based on the suspected cause of the sudden hearing loss. Treatment approaches may include corticosteroid medications, rheological drugs, vasodilators, anesthetics, and other medications chosen based on the suspected underlying pathology that caused the sudden hearing loss. The evidence supporting most treatment options for idiopathic sudden hearing loss is very weak and adverse effects of these different medications is a consideration when deciding on a treatment approach.

Epidemiology
Hearing loss (adult onset) world map - DALY - WHO2004.svg for hearing loss (adult onset) per 100,000 inhabitants in 2004:

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{{legend|#ff8400|475–520}} {{legend|#ff6e00|520–565}} {{legend|#ff5800|565–610}} {{legend|#ff4200|610–655}} {{legend|#ff2c00|655–700}} {{legend|#cb0000|>700}} ]]

Globally, hearing loss affects about 10% of the population to some degree. It caused moderate to severe disability in 124.2 million people as of 2004 (107.9 million of whom are in low and middle income countries). Of these 65 million acquired the condition during childhood. At birth ~3 per 1000 in developed countries and more than 6 per 1000 in developing countries have hearing problems.

Hearing loss increases with age. In those between 20 and 35 rates of hearing loss are 3% while in those 44 to 55 it is 11% and in those 65 to 85 it is 43%.

A 2017 report by the World Health Organization estimated the costs of unaddressed hearing loss and the cost-effectiveness of interventions, for the health-care sector, for the education sector and as broad societal costs. Globally, the annual cost of unaddressed hearing loss was estimated to be in the range of $750–790 billion international dollars.

The International Organization for Standardization (ISO) developed the ISO 1999 standards for the estimation of hearing thresholds and noise-induced hearing impairment. They used data from two noise and hearing study databases, one presented by Burns and Robinson (Hearing and Noise in Industry, Her Majesty's Stationery Office, London, 1970) and by Passchier-Vermeer (1968). As race are some of the factors that can affect the expected distribution of pure-tone hearing thresholds several other national or regional datasets exist, from Sweden, Norway, South Korea, the United States and Spain.

In the United States hearing is one of the health outcomes measure by the National Health and Nutrition Examination Survey (NHANES), a survey research program conducted by the National Center for Health Statistics. It examines health and nutritional status of adults and children in the United States. Data from the United States in 2011–2012 found that rates of hearing loss has declined among adults aged 20 to 69 years, when compared with the results from an earlier time period (1999–2004). It also found that adult hearing loss is associated with increasing age, sex, ethnicity, educational level, and noise exposure. Nearly one in four adults had audiometric results suggesting noise-induced hearing loss. Almost one in four adults who reported excellent or good hearing had a similar pattern (5.5% on both sides and 18% on one side). Among people who reported exposure to loud noise at work, almost one third had such changes.

Social and cultural aspects
People with extreme hearing loss may communicate through sign languages. Sign languages convey meaning through manual communication and body language instead of acoustically conveyed sound patterns. This involves the simultaneous combination of hand shapes, orientation and movement of the hands, arms or body, and facial expressions to express a speaker's thoughts. "Sign languages are based on the idea that vision is the most useful tool a deaf person has to communicate and receive information".

Deaf culture refers to a tight-knit cultural group of people whose primary language is signed, and who practice social and cultural norms which are distinct from those of the surrounding hearing community. This community does not automatically include all those who are clinically or legally deaf, nor does it exclude every hearing person. According to Baker and Padden, it includes any person or persons who "identifies him/herself as a member of the Deaf community, and other members accept that person as a part of the community," an example being children of deaf adults with normal hearing ability. It includes the set of social beliefs, behaviors, art, literary traditions, history, values, and shared institutions of communities that are influenced by deafness and which use sign languages as the main means of communication. Members of the Deaf community tend to view deafness as a difference in human experience rather than a disability or disease. When used as a cultural label especially within the culture, the word deaf is often written with a capital D and referred to as "big D Deaf" in speech and sign. When used as a label for the audiological condition, it is written with a lower case d.

There also multiple educational institutions for both deaf and Deaf people, that usually use sign language as the main language of instruction. Famous institutions include Gallaudet University and the National Technical Institute for the Deaf in the US, and the National University Corporation of Tsukuba University of Technology in Japan.

Stem cell transplant and gene therapy
A 2005 study achieved successful regrowth of cochlea cells in guinea pigs. However, the regrowth of cochlear hair cells does not imply the restoration of hearing sensitivity, as the sensory cells may or may not make connections with neurons that carry the signals from hair cells to the brain. A 2008 study has shown that gene therapy targeting Atoh1 can cause hair cell growth and attract neuronal processes in embryonic mice. Some hope that a similar treatment will one day ameliorate hearing loss in humans.

Recent research, reported in 2012 achieved growth of cochlear nerve cells resulting in hearing improvements in gerbils, using stem cells. Also reported in 2013 was regrowth of hair cells in deaf adult mice using a drug intervention resulting in hearing improvement. The Hearing Health Foundation in the US has embarked on a project called the Hearing Restoration Project. Also Action on Hearing Loss in the UK is also aiming to restore hearing.

Researchers reported in 2015 that genetically deaf mice which were treated with TMC1 gene therapy recovered some of their hearing. In 2017, additional studies were performed to treat Usher syndrome and here, a recombinant adeno-associated virus seemed to outperform the older vectors.

Audition
Besides research studies seeking to improve hearing, such as the ones listed above, research studies on the deaf have also been carried out in order to understand more about audition. Pijil and Shwarz (2005) conducted their study on the deaf who lost their hearing later in life and, hence, used cochlear implants to hear. They discovered further evidence for rate coding of pitch, a system that codes for information for frequencies by the rate that neurons fire in the auditory system, especially for lower frequencies as they are coded by the frequencies that neurons fire from the basilar membrane in a synchronous manner. Their results showed that the subjects could identify different pitches that were proportional to the frequency stimulated by a single electrode. The lower frequencies were detected when the basilar membrane was stimulated, providing even further evidence for rate coding.

title: Hearing loss


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Talk:Yosemite National Park

Vernal Fall
This old photograph of "Vernal Fall" might interest someone. Is it the same sight as the one pictured in the article? This angle isn't quite as dramatic. Also, the area looks more cleared out in recent photographs? Park service? Fire? Just the angle?

Candleabracadabra (talk) 17:57, 1 May 2014 (UTC)

Website links in infobox
Currently, the infobox contains three links. Even assuming they all belong in the EL section, I believe the Infobox should only contain the URL to the official http://www.nps.gov/yose/index.htm per the usage guidance at Template:Infobox protected area as well as per WP:ELOFFICIAL. --- Barek (talk • contribs) - 02:58, 15 March 2015 (UTC)
 * I agree 100% and have removed the websites of Yosemite Conservancy (which I support financially myself) and Delaware North (whose facilities I have patronized many times). I have no problem including them as external links. Cullen328  Let's discuss it  03:29, 15 March 2015 (UTC)

Yosemite as part of Northern California
To avoid the issue of edit-warring, let's discuss this debate here. As our own article on Northern California notes, the counties encompassing Yosemite National Park are commonly referred to as being part of Northern California, and the park is commonly referred to in external publications as being in Northern California. For example, "Wild Northern California," a guidebook to designated wilderness in the region, includes and describes the Yosemite Wilderness. . This is likely because while Yosemite may be closer to the "geographic center" than the northern extremity, in common practice California is roughly geographically divided in half rather than in thirds. NorthBySouthBaranof (talk) 04:00, 9 June 2015 (UTC)

Controlled use of fire by Ahwahneechee Native American Indians in Yosemite
I think somewhere this view should be mentioned, that the Ahwahneechee before they were killed or driven from the park would manage it with controlled fires and that many of the problems with wild fires are due to this absence of the resident humans who used to be part of the ecosystem there. Perhaps a short summary of this article could be a starting point for it?

Fire Over Ahwahnee: John Muir and the Decline of Yosemite

Robert Walker (talk) 23:33, 5 September 2015 (UTC)

Confusing redirects
The Yosemite Park and Curry Company redirect is targeted at this page, whereas the effectively identical Yosemite Park & Curry Company is redirected to the Ahwahnee Hotel. Could someone who knows about this sort out that mess? (I'm posting an identical note in the talk section of the latter page, too.) MrRedwood (talk) 23:39, 15 January 2016 (UTC)

 * Meanwhile, Curry Company doesn't even have a page, and isn't a redirect to anything. — Preceding unsigned comment added by MrRedwood (talk • contribs) 23:43, 15 January 2016 (UTC)

History: "first to tour the area"
"In 1855, entrepreneur James Mason Hutchings, artist Thomas Ayres and two others were the first to tour the area." This needs clarification, because indigenous people clearly "tour[ed] the area" long before any Europeans entered N America. Acwilson9 (talk) 04:29, 25 September 2019 (UTC)
 * Not necessarily.
 * If the reader doesn't know that, besides parts of the polar regions, there aren't many places on the planet that hadn't seen a human by 1855 (and most of them remote islands), the preceding section begins: "Yosemite Valley has been inhabited for nearly 3,000 years, although humans may have first visited the area as long as 8,000 to 10,000 years ago."
 * Nobody would say that Native Americans "toured the area". They didn't "tour" anything.
 * How best to clarify? "First Europeans"? Hutchings had apparently been an American citizen since 1848, and Ayres was born in New Jersey. "First people of European descent"? "First white people"? "First non-natives"? In any case, strict adherence to WP:V would require source support, and the cited source, being a book, is not easily accessible. So you'd have to go find a copy of the book or another reliable source that says what you want the article to say.
 * There is such a thing as "over-accuracy" – i.e., accuracy that is unnecessary and tends to hinder reading comprehension. ― Mandruss   ☎  02:35, 29 October 2019 (UTC)

Superintendent
Any interest in a having a sentence mention the national park's superintendent? Cindy Muldoon was named yesterday as the park's new superintendent, becoming just the second woman to hold the position. I think it's worthy of inclusion, and I'm happy to post it if there's consensus. https://www.sfchronicle.com/nation/article/Yosemite-gets-new-superintendent-in-bid-for-15678961.php Pistongrinder (talk) 19:18, 28 October 2020 (UTC)

FA criteria
There is significant unsourced content in the article, including no less than 27 citation needed tags. The article will need better referencing in order to remain a featured article. (t · c)  buidhe  21:44, 2 November 2020 (UTC)
 * , Mav is no longer editing, might you be interested in bringing this back to standard? Sandy Georgia (Talk)  00:00, 3 November 2020 (UTC)
 * I will have to put it in cue. Would like to see it updated but not sure I have time. I'll try.--MONGO (talk) 04:12, 3 November 2020 (UTC)
 * I like chasing down references. I'll take a crack at it. — hike395 (talk) 04:55, 3 November 2020 (UTC)
 * I'm willing to work on it too. Pistongrinder (talk) 19:30, 6 November 2020 (UTC)
 * @Hike395, @Pistongrinder, @MONGO: can I bring this to FAR, or do you still plan to work on this in the medium-term? FemkeMilene (talk) 18:05, 4 March 2021 (UTC)

Thanks for reminding me. I'll get back to work on it. — hike395 (talk) 00:54, 6 March 2021 (UTC)
 * still interested in working on this? Z1720 (talk) 22:05, 8 August 2021 (UTC)
 * I appreciate the reminder, @Z1720. I'll have some time next week to work on researching and adding appropriate citations to the article. Pistongrinder (talk) 16:53, 11 August 2021 (UTC)
 * Awesome. Feel free to ping me when improvements are complete and I will conduct a more thorough review. Z1720 (talk) 18:43, 11 August 2021 (UTC)
 * I've added several citations to the article over the last few weeks as you can see in the history section, but I'm not finished yet. There are still a dozen or so more tags to tackle. This is just an update to say that I'm still working on them. Pistongrinder (talk) 15:44, 10 September 2021 (UTC)

Disputing the origin of the name Yosemite and "grizzy bear"
In the Etymology section, it is stated that the name Yosemite "itself is from the Native American word 'uzumate,' which meant grizzly bear", which was taken from the source https://www.hachettebookgroup.com/travel/national-parks/the-origins-of-place-names-in-yosemite/

However, from another source http://www.yosemite.ca.us/library/origin_of_word_yosemite.html, it is explained that this name was a mistake. The one who named the National Park, Mr. L. H. Bunnell, heard the story from Major James Savage, who had a conversation with Chief Ten-ei-ya and mistakenly interpreted Ten-ei-ya. It is further explained in http://www.yosemite.ca.us/library/discovery_of_the_yosemite/04.html#page_63 that Ten-ei-ya was describing his band, which consisted of the outlaws and refugrees from other tribes, is called "grizzy bear", but not the area itself. The word "uzumate" (bear) and "yosemite" (killer), although sound similar to those who is not familiar with Miwok language, are totally distinct to native speaker in Miwok [1, 2].

Therefore it is not persuasive to use the explanation provided by the Hachette Book Group. I recommend a discussion and revision (if applicable) on this section.

BrainchildHo 🧠👶Ho   💬  08:40, 8 February 2021 (UTC)

1. Erwin G. Gudde, California Place Names, 1949, s.v.

2. Indiana University Publications in Anthropology and Linguistics, Memoir 6 of the International Journal of American Linguistics, 1951.

"Indigenous peoples' presence post war and since"
This section is rather garbled and is fundamentally incorrect in saying that there were four major evictions. In fact by 1969 only a few houses in the "Indian village" remained, solely occupied by park employees and their families who were relocated to other employee housing. The fundamental relationship in the National Park era between employment by the National Park and the right to reside the "Indian villages" is completely ignored. Eldomtom2 (talk) 15:05, 17 May 2023 (UTC)

Updating this article's European centric history
I noticed that much of this article's descriptions of the history of the region of Yosemite is focused on the history of the region with regards to European settlers. Where natives are mentioned it is often sparse and lacking sources. I plan to spend some time adjusting the language used in this article and expanding the history section to include more details about precolonial times.

I wanted to put this section here in the talk page in advance of those changes incase anyone whose interested in this page wanted to voice any concerns with this plan or wanted to help out throughout the process.

Cheers, Skoulikomirmigotripa (talk) 17:22, 15 May 2024 (UTC)
 * I think it's a great idea. No doubt, the article skews to a eurocentric context owing to the mainstream sourcing used (which is not a criticism of any previous editors). If you are able to find good sources covering the indigenous history of the area, I think it would be great to add. *But*, I would say that a more complete history of the area should be covered in History of the Yosemite area and even Yosemite Valley, while this article probably should be concerned, for the most part, on the park itself and the history since its formation. Cristiano Tomás (talk) 18:48, 15 May 2024 (UTC)
 * Yes, that's a great point! If I have the time/energy I may start the process of creating that page as well. For now though, I'll just plan on updating the history section of this page. Skoulikomirmigotripa (talk) 21:06, 15 May 2024 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Yosemite National Park


text:
Jargon

Jargon or technical language is the specialized terminology associated with a particular field or area of activity. Jargon is normally employed in a particular communicative context and may not be well understood outside that context. The context is usually a particular occupation (that is, a certain trade, profession, vernacular or academic field), but any ingroup can have jargon. The key characteristic that distinguishes jargon from the rest of a language is its specialized vocabulary, which includes terms and definitions of words that are unique to the context, and terms used in a narrower and more exact sense than when used in colloquial language. This can lead outgroups to misunderstand communication attempts. Jargon is sometimes understood as a form of technical slang and then distinguished from the official terminology used in a particular field of activity.

The terms jargon, slang, and argot are not consistently differentiated in the literature; different authors interpret these concepts in varying ways. According to one definition, jargon differs from slang in being secretive in nature; according to another understanding, it is specifically associated with professional and technical circles. Some sources, however, treat these terms as synonymous. The use of jargon became more popular around the sixteenth century attracting persons from different career paths. This led to there being printed copies available on the various forms of jargon.

Specifics
Jargon, also referred to as "technical language", is "the technical terminology or characteristic idiom of a special activity or group". Most jargon is technical terminology (technical terms), involving terms of art or industry terms, with particular meaning within a specific industry. The primary driving forces in the creation of technical jargon are precision, efficiency of communication, and professionalism. Terms and phrases that are considered jargon have meaningful definitions, and through frequency of use, can become catchwords.

While jargon allows greater efficiency in communication among those familiar with it, a side effect is that it raises the threshold of comprehensibility for outsiders. This is usually accepted as an unavoidable trade-off, but it may also be used as a means of social exclusion (reinforcing ingroup–outgroup barriers) or social aspiration (when introduced as a way of demonstrating expertise). Some academics promote the use of jargon-free language, or plain language, as an audience may be alienated or confused by the technical terminology, and thus lose track of a speaker or writer's broader and more important arguments.

Some words with both a technical and a non-technical meaning are referred to as semi-technical vocabulary: for example, Chinh Ngan Nguyen Le and Julia Miller refer to colon as an anatomical term and also a punctuation mark; and Derek Matravers refers to person and its plural form persons as technical language used in philosophy, where their meaning is more specific than "person" and "people" in their everyday use.

Etymology
The French word is believed to have been derived from the Latin word gaggire, meaning "to chatter", which was used to describe speech that the listener did not understand. The word may also come from Old French jargon meaning "chatter of birds". Middle English also has the verb jargounen meaning "to chatter", or "twittering", deriving from Old French.

The first known use of the word in English is found within The Canterbury Tales, written by Geoffrey Chaucer between 1387 and 1400. Chaucer related "jargon" to the vocalizations of birds.

In colonial history, jargon was seen as a device of communication to bridge the gap between two speakers who did not speak the same tongue. Jargon was synonymous with pidgin in naming specific language usages. Jargon then began to have a negative connotation with lacking coherent grammar, or gibberish as it was seen as a "broken" language of many different languages with no full community to call their own. In the 1980s, linguists began restricting this usage of jargon to keep the word to more commonly define a technical or specialized language use.

Fields using the term
In linguistics, it is used to mean "specialist language", with the term also seen as closely related to slang, argot and cant. Various kinds of language peculiar to ingroups can be named across a semantic field. Slang can be either culture-wide or known only within a certain group or subculture. Argot is slang or jargon purposely used to obscure meaning to outsiders. Conversely, a lingua franca is used for the opposite effect, helping communicators to overcome unintelligibility, as are pidgins and creole languages. For example, the Chinook Jargon was a pidgin. Although technical jargon's primary purpose is to aid technical communication, not to exclude outsiders by serving as an argot, it can have both effects at once and can provide a technical ingroup with shibboleths. For example, medieval guilds could use this as one means of informal protectionism. On the other hand, jargon that once was obscure outside a small ingroup can become generally known over time. For example, the terms bit, byte, and hexadecimal (which are terms from computing jargon ) are now recognized by many people outside computer science.

Referenced
The philosopher Étienne Bonnot de Condillac observed in 1782 that "every science requires a special language because every science has its own ideas". As a rationalist member of the Enlightenment, he continued: "It seems that one ought to begin by composing this language, but people begin by speaking and writing, and the language remains to be composed."

Industry term
An industry word is a specialized kind of technical terminology used in a certain industry. Industry words and phrases are often used in a specific area, and those in that field know and use the terminology.

Precise technical terms and their definitions are formally recognized, documented, and taught by educators in the field. Other terms are more colloquial, coined and used by practitioners in the field, and are similar to slang. The boundaries between formal and slang jargon, as in general English, are quite fluid. This is especially true in the rapidly developing world of computers and networking. For instance, the term firewall (in the sense of a device used to filter network traffic) was at first technical slang. As these devices became more widespread and the term became widely understood, the word was adopted as formal terminology.

Technical terminology evolves due to the need for experts in a field to communicate with precision and brevity, but often has the effect of excluding those who are unfamiliar with the particular specialized language of the group. This can cause difficulties as, for example, when a patient is unable to follow the discussions of medical practitioners, and thus cannot understand his own condition and treatment. Differences in jargon also cause difficulties where professionals in related fields use different terms for the same phenomena.

Corporate jargon
The use of jargon in the business world is a common occurrence. The use of jargon in business correspondence reached a high popularity between the late 1800s into the 1950s. In this context, jargon is most frequently used in modes of communication such as emails, reports, and other forms of documentation. Common phrases used in corporate jargon includes

 * Common share
 * Dividend
 * KPI (Key Performance Indicator)
 * Pursuant
 * ROI (Return on Investment)
 * SWOT analysis (Strengths, Weaknesses, Opportunities, and Threats)
 * Undersigned

Medical jargon
Medicine professionals make extensive use of scientific terminology. Most patients encounter medical jargon when referring to their diagnosis or when receiving or reading their medication. Some commonly used terms in medical jargon are:

 * Code blue
 * Dyspnea
 * Hematoma
 * Hypertension
 * Palliative care
 * Tachycardia

On first glance many people do not understand what these terms mean and may panic when they see these scientific names being used in reference to their health. The argument as to whether medical jargon is a positive or negative attribute to a patient's experience has evidence to support both sides. On one hand, as mentioned before, these phrases can be overwhelming for some patients who may not understand the terminology. However, with the accessibility of the internet, it has been suggested that these terms can be used and easily researched for clarity.

Legal jargon
Jargon is commonly found in the field of law. These terms are often used in legal contexts such as legal documents, court proceedings, contracts, and more. Some common terms in this profession include:

 * Acquittal
 * Affidavit
 * Adjudication
 * Libel
 * Litigation
 * Tort

Education jargon
There is specialized terminology within the field of education. Educators and administrators use these terms to communicate ideas specific to the education system. Common terms and acronyms considered to be jargon that are used within this profession include:

 * Capstone project
 * Curriculum
 * ELL (English Language Learner)
 * IEP (Individualized Education Program)
 * Pedagogy
 * PLC (Professional Learning Community)
 * STEM (Science, Technology, Engineering, and Mathematics)

In practice
Jargon may serve the purpose of a "gatekeeper" in conversation, signaling who is allowed into certain forms of conversation. Jargon may serve this function by dictating to which direction or depth a conversation about or within the context of a certain field or profession will go. For example, a conversation between two professionals in which one person has little previous interaction or knowledge of the other person could go one of at least two possible ways. One of the professionals (who the other professional does not know) does not use, or does not correctly use the jargon of their respective field, and is little regarded or remembered beyond small talk or fairly insignificant in this conversation. Or, if the person does use particular jargon (showing their knowledge in the field to be legitimate, educated, or of particular significance) the other professional then opens the conversation up in an in-depth or professional manner. Outside of conversation, jargon can become confusing in writing. When used in text, readers can become confused if there are terms used that require outside knowledge on the subject.

Positivity
Ethos is used to create an appeal to authority. It is one of three pillars of persuasion created by Aristotle to create a logical argument. Ethos uses credibility to back up arguments. It can indicate to the audience that a speaker is an insider with using specialized terms in the field to make an argument based on authority and credibility.

Jargon can be used to convey meaningful information and discourse in a convenient way within communities. A subject expert may wish to avoid jargon when explaining something to a layperson. Jargon may help communicate contextual information optimally. For example, a football coach talking to their team or a doctor working with nurses.

Accessibility and criticism
With the rise of the self-advocacy within the Disability Rights Movement, "jargonized" language has started to face repeated rejection for being language that is widely inaccessible. However, jargon is largely present in everyday language such as in newspapers, financial statements, and instruction manuals. To combat this, several advocacy organizations are working on influencing public agents to offer accessible information in different formats. One accessible format that offers an alternative to jargonized language is "easy read", which consists of a combination of plain language and images.

The criticism against jargon can be found in certain fields where professionals communicate with individuals with no industry background. In a study done by analyzing 58 patients and 10 radiation therapists, professionals diagnosed and explained the treatment of a disease to a patient with the use of jargon. It was found that using jargon left patients confused about what the treatments and risks were, suggesting that jargon in the medical field is not the best in communicating the terminology and concepts.

Jargon glossaries
Many examples of jargon exist because of its use among specialists and subcultures alike. In the professional world, those who are in the business of filmmaking may use words like "vorkapich" to refer to a montage when talking to colleagues. In rhetoric, rhetoricians use words like "arete" to refer to a person of power's character when speaking with one another.

 * Architectural terminology
 * Ballet terminology
 * Binomial nomenclature
 * Blazon (Heraldic terminology)
 * Business jargon
 * Chemical nomenclature
 * Computing jargon
 * Corporate jargon
 * Cricket terminology
 * Economics terminology that differs from common usage
 * Fencing terminology
 * Flag terminology
 * Language of mathematics
 * Mathematical jargon
 * Legal terms
 * Medical terminology
 * Musical terminology
 * Nautical terms (A-L)
 * Nautical terms (M-Z)
 * Padonkaffsky jargon
 * Poker terminology
 * Scientific terminology
 * International scientific vocabulary
 * Wine tasting descriptors

title: Jargon


text:
Bay of Biscay

The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward to Cape Ortegal. The southern area of the Bay of Biscay that washes over the northern coast of Spain is known locally as the Cantabrian Sea.

The average depth is 1744 m and the greatest depth is 4735 m.

Name
The Bay of Biscay is known in Spain as the Gulf of Biscay (Golfo de Vizcaya; Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (Golfe de Gascogne; Golf de Gasconha; Pleg-mor Gwaskogn). Its English name comes from Biscay on the northern Spanish coast, probably standing for the western Basque districts (Biscay up to the early 19th century).

Geography

Parts of the continental shelf extend far into the bay, resulting in fairly shallow waters in many areas and thus the rough seas for which the region is known. Heavy storms occur in the bay, especially during the winter months. The Bay of Biscay is home to some of the Atlantic Ocean's fiercest weather; abnormally high waves occur there. Up until recent years it was a regular occurrence for merchant vessels to founder in Biscay storms.

Extent
The International Hydrographic Organization defines the limits of the Bay of Biscay as "a line joining Cap Ortegal (43.76667°N, -7.86667°W) to Penmarch Point (47.8°N, -4.36667°W)".

The southernmost portion is the Cantabrian Sea.

Rivers
The main rivers that empty into the Bay of Biscay are Loire, Charente, Garonne, Dordogne, Adour, Nivelle, Bidasoa, Oiartzun, Urumea, Oria, Urola, Deba, Artibai, Lea, Oka, Nervión, Agüera, Asón, Miera, Pas, Saja, Nansa, Deva, Sella, Nalón, Navia, Esva, Eo, Landro and Sor.

Climate
In late spring and early summer a large fog triangle fills the southwestern half of the bay, covering just a few kilometres inland.

As winter begins, weather becomes severe. Depressions enter from the west very frequently and they either bounce north to the British Isles or they enter the Ebro Valley, dry out, and are finally reborn in the form of powerful thunderstorms as they reach the Mediterranean Sea. These depressions cause severe weather at sea and bring light though very constant rain to its shores (known as orballo, sirimiri, morrina, orbayu, orpin or calabobos). Sometimes powerful windstorms form if the pressure falls rapidly (galerna), traveling along the Gulf Stream at great speed, resembling a hurricane and finally crashing in this bay with their maximum power, such as the Klaus storm.

The Gulf Stream enters the bay following the continental shelf's border anti-clockwise (the Rennell Current), keeping temperatures moderate all year long.

Main cities
The main cities on the shores of the Bay of Biscay are Bordeaux, Bayonne, Biarritz, Nantes, La Rochelle, Donostia-San Sebastián, Bilbao, Santander, Gijón and Avilés.

History
The southern end of the gulf is also called "Mar Cantábrico" in Spanish (Cantabrian Sea), from the Estaca de Bares, as far as the mouth of Adour river, but this name is not generally used in English. It was named by Romans in the 1st century BC as Sinus Cantabrorum (Bay of the Cantabri) and also, Mare Gallaecum (the Sea of the Galicians). On some medieval maps, the Bay of Biscay is marked as El Mar del los Vascos (the Basque Sea).

The Bay of Biscay has been the site of many famous naval engagements over the centuries. In 1592 the Spanish defeated an English fleet during the Battle of the Bay of Biscay. The Biscay campaign of June 1795 consisted of a series of manoeuvres and two battles fought between the British Channel Fleet and the French Atlantic Fleet off the southern coast of Brittany during the second year of the French Revolutionary Wars. The USS Californian (1900) sank here after striking a naval mine on 22 June 1918. In 1920 the SS Afrique (1907) sank after losing power and drifting into a reef in a storm with the loss of 575 lives. On 28 December 1943, the Battle of the Bay of Biscay was fought between HMS Glasgow (C21) and HMS Enterprise (D52), and a group of German destroyers as part of Operation Stonewall during World War II. The area became known as the "Valley of Death" by U-boat crews following a series of repeated losses from RAF attacks on U-boats from 1943 untill the end of the war. The GS U-667 sank on 25 August 1944 in position 46°N, -1.5°W, when she struck a mine. All hands were lost.

On 12 April 1970, SOVIET SUBMARINE K-8 sank in the Bay of Biscay due to a fire that crippled the submarine's nuclear reactors. An attempt to save the sub failed, resulting in the death of forty sailors and the loss of four nuclear torpedoes. Due to the great depth (15,000 ft), no salvage operation was attempted.

Plaiaundi Ecology Park
The Plaiaundi Ecology Park is a 24 -hectare coastal wetland lying where the Bidasoa River meets the sea in the Bay of Biscay.The nature of Plaiaundi consists of a wide variety of flora (visitors view them mainly in the spring) and fauna (visitors with binoculars arrive all during the year, because of the birds' migratory habits). This nature park contains a variety of birds, reptiles, mammals and insects.

Marine mammals
The car ferries from Gijón to Nantes/Saint-Nazaire, Portsmouth to Bilbao and from Plymouth, Portsmouth and Poole to Santander provide one of the most convenient ways to see cetaceans in European waters. Often specialist groups take the ferries to collect more information. Volunteers and employees of ORCA regularly observe and monitor cetacean activity from the bridge of the ships on Brittany Ferries' Portsmouth to Santander route. Many species of whales and dolphins can be seen in this area. Most importantly, it is one of the few places in the world where the beaked whales, such as the Cuvier's beaked whale, have been observed relatively frequently. Biscay Dolphin Research monitored cetacean activity from the P&O Ferries cruise ferry Pride of Bilbao, on voyages from Portsmouth to Bilbao.

North Atlantic right whales, one of the most endangered species of whales, once came to the bay for feeding and probably for calving as well, but whaling activities by Basque people almost wiped them out sometime prior to the 1850s. The eastern population of this species are considered to be almost extinct, and there has been no record of right whales in the Bay of Biscay except for a pair in 1977 (possibly a mother and calf) at 43°N, -10.5°W, and another pair in June 1980. Other records in the late 20th century include one off Galicia at 43°N, -10.5°W in September 1977 reported by a whaling company and another one seen off the Iberian Peninsula.

The best areas to see the larger cetaceans are in the deep waters beyond the continental shelf, particularly over the Santander Canyon and Torrelavega Canyon in the south of the Bay.

The alga Colpomenia peregrina was introduced and first noticed in 1906 by oyster fishermen in the Bay of Biscay.

Grammatostomias flagellibarba (scaleless dragonfish) are native to these waters.

title: Bay of Biscay