By Melanie Lewis, RHAD, PCGE
Melanie Lewis, RHAD, PCGE
Age-acquired hearing loss is a natural decline in hearing ability that affects 80% of those over the age of 70. In fact, based on Kochkin’s 2008 survey,{{1}}[[1]]MarkeTrak VIII[[1]]35 million Americans are thought to present with the symptoms of hearing loss, with the largest demographic being “over 70.”
In recent years, several high-profile studies have drawn a link between the acceleration of dementia and untreated hearing loss. In this article we hope to offer some elucidation regarding the impact of presbyacusis (age-related hearing loss) and also underscore why it is increasingly being linked to cognitive disorders such as dementia.
Natural Hearing Degeneration
The cochlea of the human inner ear contains thousands of tiny hair cell receptors (cilia) that are vital in transforming the mechanical energy of sound waves into electrical impulses. These electrical impulses are responsible for relaying information to the brain via the auditory nerve and ultimately ensure that sound information is transformed into a lexicon we can understand. As we grow older the number and quality of these hair cells diminish and certain frequency regions, initially of the higher speech range, begin to degrade.
The body is unable to re-grow or indeed regenerate replacement hair cells, so the resultant loss is permanent. For most presbyacusis losses deterioration occurs very slowly over a number of years, usually affecting both ears to a similar degree.
While hearing loss can start in one’s middle years, hearing difficulties do not often manifest themselves as a “problem” until over the age of 65. To date there is no known cure for age-related hearing loss, but there is significant progress in the effective management of the condition.
Hearing Loss Manifestation
Hearing loss is typically compartmentalized into an audiometric classification ranging from mild to profound. The level of intervention depends on the extent of this evaluation and whether difficulties may be remediated by medical intervention or through use of external amplification, such as hearing aids.
The main areas of concerns are often cited as difficulties hearing women’s, children’s, or softly spoken voices; hearing in high levels of background noise; the telephone/doorbell ringing and poor sound fidelity for certain television programmes.
While these complaints may seem small in a singular contex,t the collective strain of trying to manage and organize these sounds on a daily basis can pose both physical and mental challenges.
Hearing Loss and Dementia
As previously touched upon, the use of hearing aids to address deficits at specified frequencies can be an effective management strategy, but one that, sadly, is not always employed. There is no singular justification for why an individual does not seek the appropriate support, but a host of reasons, including “other” priorities, a sense of shame or embarrassment in admitting a loss, or, more simply, lack of awareness that hearing loss may be ameliorated.
According to Johns Hopkins Medical research, those over age 65 with unmanaged hearing loss are at greater risk of developing dementia or Alzheimer’s Disease. While the link between hearing loss and dementia is unknown, there seems to be a corollary between the onset of dementia and reduced auditory stimulus; the latter perhaps, if not the direct cause, then certainly an accelerant of the condition:
“Compared to individuals with normal hearing, people with mild, moderate, and severe hearing loss, respectively, had a two, three, and five-fold increased risk of developing dementia,” said Frank Lin, M.D., an otolaryngologist and epidemiologist at Johns Hopkins School of Medicine in Baltimore.
The study underscores two central aspects linking hearing loss and dementia: cognitive overload and social isolation. It is believed that the resources one expends in trying to follow a conversation may overwhelm or overload the brain; factor this strain in with (often self-imposed) social isolation and the risk is magnified. Social isolation is a real possibility when hearing loss is left unmanaged.
Recommended Actions
It is essential for those who show symptoms of hearing loss or who are concerned about changes in their hearing level that a full diagnostic test be performed. The hearing test is designed to evaluate the type and degree of one’s hearing level against a normative value and determine the most effective intervention program.
For most age-related hearing loss the recognized intervention strategy is hearing aids. The proliferation of digital hearing systems ensures that amplification can be targeted to the specific end user’s requirements, addressing specific frequency deficits while trying to restore comfortable and natural sound reproduction. While it’s true that hearing aids cannot cure hearing loss, they are often responsible for enabling and indeed maintaining, continued social interaction.
*featured image: Alzheimer’s Association
Melanie Lewis, RHAD, PCGE is an audiologist and Registered Hearing Aid Dispenser in the UK who worked for many years at H.S Audiological Centres before moving to head the Hearing Direct audiology department in 2012.
