Cognitive decline and enhancement
In 1984 Dr. Shlomo Silman demonstrated, when hearing-impaired people wore only one hearing aid, their brains lost the ability to hear speech clearly from the side that was not receiving sound stimulation.
In other words, if you don't use the ear, you lose the ability to hear speech clearly.
When Dr. Gil first opened his office in Walnut Creek he was shocked to find very low speech understanding scores with the new clients coming into his office.
He discovered, they were all grossly misfit. They were mostly under-fit. (Dr. Gil presented what he believed to be the cause of this common mis-fitting of hearing aids in "The Missing Link")
He knew long-term sound deprivation resulted in withdrawal, psychological ailments, cognitive deficiencies, and a host of issues that made a person prematurely aged.
Properly fit hearing aids can reduce these deprivation created ailments.
In many cases, individuals recover their cognitive abilities with proper hearing correction.
Joan Knapp is a fictitious name for an actual client whose story needs to be told, and whose privacy should to be respected. The data described are taken from Dr. Gil's client files with her approval.
For most of Joan Knapp's interesting life, she had no difficulty with her hearing. In 1986, when she was 65, she realized her developing hearing loss was affecting her relations with those she loved most.
During the next 19 years she purchased several sets of hearing aids from local audiologists and hearing aid dispensers in the Walnut Creek area. The aids provided some help but her hearing abilities and her social life continued to become more and more challenging.
In 2005, she was 84 years old when she heard about Dr. Gil and his new office just outside of her Rossmoor Senior Community.
Dr. Gil found a moderate hearing loss on her left side. The right ear bordered on a severe hearing loss. But that is not what shocked Dr. Gil. Joan's ability to understand the words read to her was only 40% of the words correct, on her better ear. The sound was loud enough for Joan to hear all of the speech sounds she needed to get the words correct, but her brain was not capable of transforming that sound into words.
Using the real ear measurement equipment he developed, Dr. Gil was able to quickly ascertain that she was not receiving the type of hearing correction to avoid that severe deterioration in her speech understanding abilities.
At her "Demo", Joan experienced an "amazing" improvement in her ability to hear both sound and speech. That resulted in an immediate improvement to her quality of life. But that wasn't to be the most significant change.
Over the next four years, wearing the hearing aids provided by Dr. Gil, her brain's ability to understand words improved. Her speech understanding scores doubled from 40% words correct to over 80% words correct indicating dramatic cognitive enhancement.
Cognitive enhancement is a typical occurrence with Dr. Gil's clients. The vast majority of new clients seen in 2005, the year Joan came in, saw their speech understanding improve more than 20%. A third of those clients increased their speech understanding scores by 30%-65%.
In 2010 A New Challenge: When Joan returned for her annual hearing test and hearing aid retuning sessions, Dr. Gil discovered a huge drop in Joan's speech understanding scores down to their levels of five years earlier. Dr. Gil and his staff had seen this type of occurrence many times with other clients he tracks in his database.
Sometimes it correlates with the stress of caring for a disabled spouse, loss of a loved one, or depression resulting in an unwillingness to put their hearing aids in one or both of their ears. Or, it could be related to other factors including medication side effects, a minor stroke or other nerve damaging processes. In Joan's case it appeared to be stress caused by a physical condition that was being medically treated. The medications she was taking during that time did not list hearing or cognitive impairment as side effects.
Dr. Gil continued to retest Joan as her medical treatment had its effect. Six months after registering the poor understanding levels, her understanding scores returned back to their pre-illness levels.
The decrease in Joan's cognitive function that occurred by 2005 should probably not have developed. Dr. Gil attributes the decline to the difficult technical challenge that hearing aid providers face in trying to properly fit hearing aids to individual hearing and cognitive needs.
Hearing aids are generally designed to be "fast and easy" to fit to an "acceptable" level. However, Consumer Reports said two-thirds of the hearing aids purchased by their research subjects were "misfit". Dr. Gil believes the traditional presentation of amplification does not provide sound appropriately to maintain cognitive function.