Hearing loss may range from a slight reduction in auditory acuity to complete deafness. Deafness due to inner ear dysfunction are referred to as sensorineural hearing loss, in which some frequencies are heard less well. These may be the high frequencies (4000 or 8000 Hz) as in presbyacusis or lower frequencies such as in Ménière’s disease..
Irrespective to type of hearing loss, it places the patient in a state of disability which could be termed multidimensional: sensory disability, communication disability, social disability.
Inevitable, a hearing impaired person is isolated from social (family meals, eating out at restaurants, parties or activities with friends, etc.) and professional life due to hearing loss further complicated by psychological complications (fear of miscommunication, fear of ridicule or fear of being a burden). Additional fatigue is incurred by the need for highly concentrated effort required to understand or follow even a simple conversation. The impact of hearing loss can affect three major dimensions:
Hearing loss can occur suddenly or develop gradually.
Presbycusis is a progressive hearing loss due to aging of inner ear tissue. The risk factors are a genetic predisposition, regular early exposure to noise, toxic environmental factors or the use of some medical drugs. This type of progressive deafness more commonly affects men than women, from the age of 50 years old onwards. Although aging of the inner ear is a normal effect due to loss of hair cells, it may be accelerated or potentiated by the risk factors described above. There is currently no curative or preventative treatment for presbycusis.
So far, a hearing aid is the only current means of restoring the lost auditory acuity. This solution has several disadvantages: the need to wear it regularly or even permanently, price and stigmatisation. Although very small, these instruments perpetually remind patients that they are getting old and that this is visible. Because of these disadvantages patients prefer to avoid a hearing aid with the risk of social and occupational isolation! There is therefore a real and important need for a treatment against this damage.
Sudden sensorineural hearing loss may occur over 24h. The causes of this remain very contentious and may be due an acoustic trauma or viral, vascular, immune or mechanical in origin. The hearing loss is often unilateral and peripheral in nature. In 2/3 cases the hearing recovers untreated over around a fortnight. The current treatment offered is corticosteroid therapy, the effectiveness and therefore utility of which are disputed. It would therefore be important to have access to an effective treatment which is straightforward to administer.
Finally, congenital pressure related inner ear deafness is related to excess pressure from the fluid contained in the inner ear on the auditory sensory structures. The current treatment offered is surgical, but again it would be useful to offer treatment against the injury or curative treatment for the causes of liquid changes.