Q: I’m getting older and noticing that I can’t hear as well as I used to. Should I look into whether or not I'm losing my hearing?
A: Hearing loss is one of the most common sensory disabilities. It is the third most common chronic health condition in older adults, and it is expected to become more common with our aging population. Yet, many people with hearing loss are unaware they are missing sounds in their life. Often friends and family members notice first. Should you or a family member notice you are not hearing what you should be, it is wise to have your hearing assessed. In many respects, the ear is like a muscle – if you don’t use it, over time it will waste away (atrophy), and when you then try to use it years later you can never get it as strong.
A hearing assessment can be done in your community by visiting a local business that sells hearing aids. The cost for testing is typically included in the purchase of a hearing aid. Staff are knowledgeable about red flag conditions that may require further assessment by an otolaryngologist prior to fitting hearing aids. These include sudden hearing loss, asymmetrical hearing loss, associated discharge or pain, and associated dizziness.
Q: Why is it important that I wear a hearing aid if my audiologist or doctor recommends one?
A: There is increasing evidence of the deleterious effects of hearing loss on the human brain, in particular the association between hearing loss and cognitive decline in older adults. This is concerning given that the prevalence of hearing loss is increasing dramatically with the aging of our population.
Recent studies show that the severity of hearing loss in older adults is correlated with accelerated cognitive decline. Adults with hearing loss showed 30 to 40 per cent greater progression of cognitive decline and those with severe hearing loss were five times more likely to develop dementia over a six-year period compared to those with normal hearing. If this association between hearing loss and cognitive decline is indeed causal, then wearing hearing aids (or cochlear implants if hearing aids are no longer effective) is hoped to mitigate the risk.
Q: What is the difference between a hearing aid and a cochlear implant?
A: Hearing aids are effectively mini-amplifiers. They have a microphone that detects sound and a speaker that then presents amplified sounds in the ear canal to allow improved hearing.
Cochlear implants use very different technology. They consist of two components:
- an implanted mini-computer that is placed under the skin with an electrode array that is inserted into the cochlea or organ of hearing, and
- an external sound processor. The processor has a microphone that detects the sound. The sound information is then transmitted wirelessly through the skin (along with energy to power the internal device). The internal receiver then coverts the information to an electrical signal that is sent into the cochlea to stimulate the nerve endings.
Cochlear implants are the last resort for hearing-impaired individuals and are only considered when hearing aids are no longer working well enough to allow people to hear. Cochlear implants are typically reserved for people with severe-profound hearing loss in both ears, and to be a candidate they must meet strict audiologic, radiologic and medical criteria.
Q: What new research is taking place around cochlear implants and stem cell therapy?
A: Stem cells offer many potential benefits to those with hearing loss. Most hearing loss occurs due to sensory hair cell loss in the organ of hearing, the cochlea. Ideally, stem cell treatment would restore these lost hair cells. However, there are many challenges in using stem cells for such hair cell restoration. The cochlea is housed in dense bone and within an immune-privileged area; much the same as there is a blood-brain barrier, there is a blood-labyrinth barrier, and both impede access of stem cells to the inner ear.
Researchers are looking at different approaches—this involves using paramagnetic particles within stem cells and magnetic fields to direct stem cells from the peripheral circulation into the cochlea. Although not yet successful in restoring lost hair cells, this technique has proven useful in protecting and/or restoring the function of residual hair cells before they are irrevocably lost.