Hearing Impairment, Cognitive Decline, and Amplification
Multiple studies have indicated that hearing loss may be a significant factor with regard to cognitive decline in older adults. Although speculative, perhaps the association between hearing loss and cognitive impairment could both be the result of an underlying common pathology such as vascular disease or inflammation. Other explanations include variations of mechanistic hypotheses such that hearing loss leads to increased isolation and loneliness and increased cognitive load and more.
Recently, Mosnier et al (2015) concluded hearing rehabilitation through cochlear implantation “results in improvements in speech perception and cognitive abilities and positively influences their social activity and quality of life.”
Deal et al (2015) tested the hypothesis that hearing impairment (HI) is associated with lower cognitive function. The authors evaluated 253 people with a mean age of 77 years. Cognitive evaluations were performed in 1990-1992, 1996-1998, and in 2013. Linear regression and estimating equations were used to predict anticipated trajectories over the 20-year period. Hearing was assessed using pure-tone averages (PTAs) from 500 to 4000 Hz in the better ear and subjects were categorized into normal, mild, and moderate/severe hearing loss.
In essence, Deal and colleagues found that when comparing people with normal PTAs to those with moderate/severe hearing loss, the rate of decline over the 20-year period differed by approximately one-half of a standard deviation with regard to memory and one-third of a standard deviation with respect to global function and declines were greatest among participants who had not worn hearing aids, adding to limited findings with regard to cognitive impairments associated with hearing loss. However, and of significant importance, the authors report the effect of amplification on cognitive decline remains unknown.
They report that “in this pilot study…(of) 253 white ARIC Neurocognitive Study participants …from Maryland (mean age = 77 years), our results demonstrated that moderate/severe HI measured in late life was associated with poorer concurrent memory performance and with a faster rate of prior 20-year decline in both memory and global cognitive function. Although, on average, all participants with moderate/severe HI declined in all three domains, the greatest decline was estimated for participants who reported not using a hearing aid.” They state that “ in conclusion, this study documented a moderate association between moderate/severe HI and memory performance, both at the time of hearing testing and over the prior 20 years, in 253 white men and women from Washington County, Maryland (and) this association was strongest among persons with moderate/severe HI who reported not wearing a hearing aid. These findings lend support to the hypothesis that HI may be a risk factor for cognitive decline in older adults and that hearing aid use could possibly reduce that risk….”
For More Information, References, and Recommendations
Beck DL, Edwards B, Pichora-Fuller MK. (2011) Exploring the maze of the cognition-audition connection. Hearing Journal 64 (10):21-24.
Beck DL, Edwards B, Humes LE, Lemke U, Lunner T, Lin FR, Pichora-Fuller MK. (2012) Expert roundtable: issues in audition, cognition, and amplification. Hearing Review.
Deal JA, Sharrett AR, Albert MS, Coresh J, Mosley TH, Knopman D, Wruck LM, Lin FR. (2015): Hearing Impairment and Cognitive Decline: A Pilot Study Conducted Within the Atherosclerosis Risk in Communities Neurocognitive Study Am. J. Epidemiol.181(9):680-690.
Mosnier I, Bebear J, Marx M, et al. Improvement of Cognitive Function After Cochlear Implantation in Elderly Patients. JAMA Otolaryngol Head Neck Surg.