Lately, there has been a lot of “hype” about the use of amplification and Dementia. At least in the US, the ads hocking hearing instruments from many of the manufacturer-owned, hearing aid sales operations lead patients to believe that if they purchase hearing instruments they will cure dementia, and even Alzheimer’s Disease. Too bad that this is not true as it would be an easy treatment option to cure this terrible disease. While the cause of this dreaded disease has been attributed to everything from Teflon-coated pans to genetics, there is no specific cause of the disorder. Physicians and audiologists have hypothesized for quite some time that hearing impairment probably contributes to the everyday cognitive difficulty encountered by dementia patients and their families. If hearing impairment does contribute to cognitive dysfunction, a higher prevalence of hearing impairment in people with dementia than people without should be measured. In addition, the worse the dementia the more hearing impairment should be noted as well.
Is There a REAL Hearing Connection?
Although previous studies of hearing and cognition in older adults have consistently demonstrated these conditions to be associated, the associations have not always been statistically significant. These studies have sometimes been criticized for low statistical power, imprecise diagnostic criteria and instrumentation, and failure to control for potentially confounding variables such as age and depression.
Evidence is mounting, however, that hearing loss in older patients is not just a relatively benign condition that, at worst, leads to frustrated family members who can’t make themselves heard. Recent research by at least two independent groups has shown a strong association between hearing loss and cognitive decline. The results are troubling enough to cause one investigator to call for an “all-hands-on-deck” push to make age-related hearing loss a public health priority.
One of the studies funded by the National Institutes of Health conducted by Lin et al. (2013) at Johns Hopkins, suggested that about 50% of their hearing-impaired older patients had dementia when compared to their “normal hearing” older adult control subjects. Frank R. Lin, MD, PhD, an assistant professor in the division of otology, neurotology and skull base surgery at Johns Hopkins School of Medicine, assistant professor in the division of geriatric medicine in the Johns Hopkins Center on Aging and Health and assistant professor in the departments of epidemiology and mental health at the Johns Hopkins Bloomberg School of Public Health in Baltimore, said, “My collaborators at the National Institute on Aging (NIA) were very surprised at the strength of the association.”
The study in the NIH-sponsored Baltimore Longitudinal Study of Aging was one of Dr. Lin’s first to show such a strong link between hearing loss and dementia. The study included 639 participants, most of whom were between 60 and 80 years of age. At baseline, none of the participants had any evidence of cognitive impairment, although some had hearing loss. During a median follow-up of 11.9 years, 58 cases of incident all-cause dementia were diagnosed, of which 37 were considered to be Alzheimer’s disease. The risk for participants developing dementia “increased linearly with the severity of hearing loss,” Dr. Lin said. Compared with normal hearing, the hazard ratio (risk) for dementia was 1.89 (1.00–3.58) for mild hearing loss, 3.00 (1.43–6.30) for moderate hearing loss and 4.94 (1.09–22.40) for severe hearing loss.
These results were supported by a subsequent study of nearly 2,000 patients by Lin et al. (2013) and further supported by Gallagher et al (2012) in another study by an independent group in the U.K.
Recently, in the ENT and Audiology News, a noted Canadian researcher, Dr. Kathleen Pichora-Fuller, stated that “we must go beyond simply testing hearing and amplifying sound if progress is to be made in helping those who are hard of hearing remain actively engaged in communication and social interaction. The need to assess the role of cognition in more realistic listening situations using new behavioral and physiological approaches.”
Dr. Pichora-Fuller further observes that the connection between hearing and cognition has gained new importance recently as literature does now show some indication that older adults who are hard of hearing are at greater risk than their normally hearing peers for clinically significant cognitive decline.
Hearing Aids and Dementia?
So, the jury is now in …… the literature that suggests dementia and Alzheimer’s patients should be screened and/or evaluated for hearing impairment. NIH studies now indicate that these patients might be better connected to friends and family if they have amplification to assist them with their everyday communication needs. While hearing instruments are probably beneficial to these patients, families need to insure that they do not simply make a purchase to cure the disorder. The introduction of amplification should to be one component of an active treatment program for dementia and Alzheimer’s patients, not merely a purchase.