QUESTION: At age 82 my mother was in a coma for 11 days due to a knee replacement. She had always been very hard of hearing, wore those aids that you put in the bra with the cord going up to the ear until better ones were made. She could hardly hear without aids.
When she came out of the coma she could hear a lot better (the family all noticed this, but it did not last). I asked several doctors what happened that she could hear so well, but they could not understand such a thing (don't think they believed me). She could hear better, but her mind was never the same.
My question is - what could have happened that made her hear so much better for a short time? She died at age 90 and I am still wondering about this. Hope you have an answer, thank you.
ANSWER: Hi Helen,
While it is known that sudden hearing loss can occur as the result of surgery (thought to be a result of vascular insult/interruption or system trauma/stress), improvements from non-auditory type surgery is not well-documented. So,this is a very interesting and difficult to answer question. Other than knowing that there was a significant hearing impairment, we really do not have any information on possible causes or the mechanism/site(s) of involvement (ie, which point along the complex auditory system is damaged or affected). Therefore, we can merely speculate.
What you describe is a the perceived improvement of functional hearing ability. Functional ability is the combined result of the peripheral auditory system (outer ear, middle ear, inner ear, auditory nerve), central auditory system (auditory centers within the brainstem and auditory cortex), and other central and cognitive abilities (speech and language centers). Unfortunately, even if we had pre- and post- audiological test results, such as an audiogram and word and speech understanding scores, we probably still would not know for certain.
The common understanding about most typical hearing losses are that they are the result of damage/loss of inner ear sensory cells, called hair cells, which do not repair or regenerate. Once they are lost, they do not come back. In addition, the nerve fibers that connect to these sensory cells are often lost or dysfunctional. This used to be referred to as "nerve deafness" but is now more accurately described as sensori-neural hearing loss.
That being said, there are specific hearing disorders that have been known to cause fluctuations in hearing (including improvements), such as Meniere's disease (endolymphatic hydrops) which is an intracochlear (inner ear) fluid regulatory problem, or hormonal and autoimmune changes which have been suspected as a cause for hearing change, but these are not typical and usually are known causes or have other severe symptoms (severe bouts of vertigo, tinnitus, and ear pressure).
So, what do I think? While it is not very likely that components of the peripheral auditory system improved or repaired themselves, I could imagine a change in nerve and cognitive performance/sensitivity/processing that could result in a more global improvement in sound awareness and communication ability.
I hope my explanation and answer is of some help.
---------- FOLLOW-UP ----------
QUESTION: Thank you so much for your quick reply. I think my mother had "nerve deafness". Both myself and my brother also have it. My brother got it in his early 30's and I got it in my 40's. After she married she asked a doctor if her hearing impairment was hereditary as she did not want to have children if they suffered the same. Unfortuanately doctors at that time did not know so here we are with nerve deafness. I don't think she regrets having us at all. She was a wonderful mother and the new hearing aids are much better then when she was young.
You are very welcome. Severe hearing losses which come at earlier ages and are not tied to some environmental insult (noise, meds,etc) are often hereditary/genetic in nature. And, I understand your mother's concern about passing this on, although I am sure she did not have regrets either:)