A question I am regularly asked when patients are recommended hearing aids as treatment for hearing loss is, ‘Can there not be anything done medically? So I thought about those patients when I read this recent research study.
An injection of a drug led to the creation of new hair cells in tests on mice, they have been grown using a similar principle to stem cells. The hair cells are not ‘hairs’ as such but are the nerve terminals for the eight nerve pathway. Normal hearing however was not restored, rather the mice went from hearing nothing to detecting loud sounds such as a slamming door or traffic noise. Experts are “tremendously excited” however warned treating humans was still a distant prospect, at least a decade. To hear anything, sound pressure or sound waves have to be converted into electrical signals which the brain then interprets as sound. This happens in the inner ear where vibrations from the basilar membrane activate tiny hairs (nerve terminals), the movement creates an electrical signal which is transmitted along the auditory nerve to the brain. Most hearing problems are as a result of acquired damage to these hairs, via noise, infection or ototoxic drugs.
When I was studying at the Ear Institute there was similar work being done there. One of the questions I put forward at the time was ‘How will you correctly innervate the hair cells to the appropriate auditory nerves?’ As the main problem lies in the fact that the entire auditory system is frequency specific / frequency coded, therefore re-innervating them correctly to the appropriate auditory nerves maybe difficult. Incorrect wiring will lead to an unfamiliar or incorrect transmission of sound frequency and intensity. Therefore simply regrowing these cells may not restore hearing or at least not in a way that would be perceived as normal.
If you can not wait another decade for stem cell treatment, and would like to improve your hearing now contact us at chalfont hearing on 01494 765144 or visit the rest of the website for treatment options chalfonthearing.co.uk