Starkey Research & Clinical Blog

Another piece in the puzzle of hearing aid use and cognitive decline

Amieva, H., Ouvrard, C., Giulioli, C., Meillon, C., Rullier, L. & Dartigues, J.F. (2015) Self-Reported Hearing Loss, Hearing Aids and Cognitive Decline in Elderly Adults: A 25-Year Study. Journal of the American Geriatric Society 63 (10), 2099-2104.

This editorial discusses the clinical implications of an independent research study and does not represent the opinions of the original authors.

Of individuals age 65 or older 30% will have some hearing loss, among those of age 85 or older this proportion is estimated at 70-90% (Chien & Lin, 2012; Weinstein, 2000). Many individuals with hearing loss go without hearing aids, if causal linkage exists between increased risk of cognitive decline or dementia due to untreated hearing loss the implications are of meaningful concern for a large population of older adults. These factors have motivated a swell of interest in relationships among declining of hearing ability, cognition, and memory for our aging population.

Though the ways in which hearing loss is related to cognition and memory deficits are not fully understood, recent evidence suggests that hearing loss may have a meaningful relationship to increased risk of cognitive decline (Deal et al., Lin et al., 2011; Ohta et al., 1981; Granick, et al., 1976; Lindenberger & Baltes, 1994). Some reports also suggest that treatment of hearing loss with the use of hearing aids may slow the progression of cognitive decline, though more study is needed to support this proposition (Valentijn et al., 2005; Lin et al., 2013; Deal et al., 2014).  It is known, however, that hearing loss increases social isolation in the elderly (McCoy et al., 2005; Tun et al., 2009; Weinstein & Ventry, 1982) and social isolation is in turn linked to increased cognitive decline. Whether hearing loss has a direct or circuitous connection to cognitive decline and whether treating hearing loss can slow the rate of cognitive decline is still in question. The purpose of the study reviewed here was to examine self-reports of hearing loss and compare the rates of cognitive decline, or cognitive trajectories among normal hearing and hearing-impaired subjects, and among those who wear hearing aids and those who do not.

Amieva and colleagues completed an analysis of 3,670 subjects, age 65 or older who were participating in a French longitudinal study of aging and the brain. The study began 25 years ago with an initial neuropsychological evaluation, indices of dependency, depression and social interactions, as well as a brief questionnaire about hearing loss. Subsequent visits took place at 2-3 year intervals after the initial visit and again included tests of cognitive performance and complaints, functional ability and symptoms of depression, as well as questions about social interactions and pharmaceutical use. The Mini-Mental State Examination (MMSE; Folstein et al., 1975) was used as a measure of global cognitive performance. To gauge self-perceived hearing loss, subjects were asked “Do you have hearing trouble?” and were instructed to choose one of 3 responses:

1.  “I do not have hearing trouble.”

2.  “I have trouble following conversation with two or more people talking at the same time or in a noisy background.”

3.  “I have major hearing loss.”

In addition to the inquiry about perceived hearing loss, participants were asked if they had a hearing aid.

Participants were divided into three groups based on perceived hearing loss: 2,394 (65%) subjects reported no hearing trouble, 1139 (31%) reported difficulty in groups or noise and only 137 (4%) reported major hearing loss. To examine the effect of hearing loss on the cognitive trajectories, subjects were divided into only two groups: those without perceived hearing loss and those who reported either moderate or severe hearing loss. Of the 1276 subjects who reported hearing loss, 150 used hearing aids. Of the 150 hearing aid users, 89 had self-reported moderate loss and 61 had self-reported severe loss.

Data analysis was comprised of three statistical models. The first model examined the relationship between hearing loss and cognitive decline. After controlling for age, gender and education, the investigators found that hearing loss was significantly related to lower scores on the MMSE and greater decline in cognitive performance over 25 years. The second statistical model examined the relationships among hearing loss, hearing aid use and cognition. At the baseline appointment, both hearing-impaired groups (moderate and major hearing loss) had lower scores on the MMSE than did the subjects with no reported hearing loss. Over the 25 years following the initial visit, there was a significant difference in the rate of cognitive decline between the group of hearing impaired individuals who did not wear hearing aids and the subjects with no reported hearing loss. In contrast, the individuals who did wear hearing aids showed no difference in cognitive trajectory from normal-hearing subjects.  A third statistical model examined hearing aids, hearing loss and cognition, while controlling for several other variables: comorbidities, dependency, dementia and psychotropic drug use. After these factors were controlled, there was no longer a significant difference between the cognitive trajectories of the sub-groups of hearing impaired subjects.

The current study is in agreement with previous reports of a relationship between hearing loss and increased rates of cognitive decline (Lin, 2011; Lin et al., 2013; Deal et al., 2015).  Of particular note is that the individuals who wore hearing aids had similar rates of cognitive decline to normal hearing individuals and slower trajectories than hearing impaired subjects who did not wear hearing aids; this significant difference based on hearing loss disappeared when other variables including depression were controlled. The authors point out that hearing loss has been associated with depression and social isolation in previous studies (Kiely et al., 2013; Li et al., 2014) and that these factors may be the mediate the relationship between hearing loss and cognitive decline.  In other words, the findings of the current study suggest that there may not be a direct relationship between hearing loss and cognitive decline.

It is important to note is that this study used self-report as the measure of hearing loss and hearing aid use. The self-report technique was likely a less expensive and more logistically feasible option, given the magnitude of the study. Additionally, self-reported hearing loss was only measured at the initial visit, so the subjects’ progression of hearing loss was unknown. With particular relevance to the current discussion, cognitive status may indeed affect a person’s perceived ability to communicate in daily activities, particularly in noise. However, individuals who experience difficulty functioning in noise due to cognitive or memory constraints may or may not have elevated pure tone thresholds. Therefore, the self-report measurement may not represent actual hearing loss but could instead reflect other subject characteristics. If audiometric testing is not done, it is unclear how hearing loss may affect performance on measures of cognition.

The evidence presented by Amieva  adds mild insight to our collective understanding of the relationships between hearing status and cognitive ability. Caution must still be maintained when suggesting that treatment of hearing loss may slow or attenuate cognitive decline. Deeper understanding will require additional longitudinal studies with thorough diagnostic routines and randomized, controlled experimental designs. Thankfully this work is underway at universities and hospitals in the United States and Europe. Some pilot outcomes were reviewed in an earlier blog and are available in the original article.

References

Amieva, H., Ouvrard, C., Giulioli, C., Meillon, C., Rullier, L. & Dartigues, J.F. (2015) Self-Reported Hearing Loss, Hearing Aids and Cognitive Decline in Elderly Adults: A 25-Year Study. Journal of the American Geriatric Society 63 (10), 2099-2104.

Chien, W. & Lin, F. (2012). Prevalence of hearing aid use among older adults in the United States. Archives of Internal Medicine 172, 292-293.

Deal, J., Sharrett, A., Albert, M., Coresh, J., Mosley, T., Knopman, D., Wruck, L. & Lin, F. (2015). Hearing impairment and cognitive decline: A pilot study conducted within the Atherosclerosis Risk in Communities Neurocognitive Study. American Journal of Epidemiology 181 (9), 680-690.

Desjardins, J. & Doherty, K. (2013). The effect of hearing aid noise reduction on listening effort in hearing-impaired adults. Ear and Hearing 35(6), 600-610.

Ferrite, S., Sousa-SantanaII, V. & Marshall, S. (2011). Validity of self-reported hearing loss in adults: performance of three single questions , Revista de Saúde Pública 45(5), 824-30

Folstein, M., Folstein, S. & McHugh, P. (1975). “Mini Mental State”, a practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 12, 189-198.

Granick, S., Kleban, M. & Weiss, A. (1976). Relationships between hearing loss and cognition in normally hearing aged persons. Journal of Gerontology 31, 434-440.

Kiely, K., Anstey, K. & Luszcz, A. (2013). Dual sensory loss and depressive symptoms: the importance of hearing, daily functioning and activity engagement. Frontiers in Human Neuroscience 7, 837.

Li, C., Zhang, X. & Hoffman, J. (2014). Hearing impairment associated with depression in U.S. adults. National Health and Nutrition Examination Survey 2005-2010. Journal of the American Medical Association, Otolaryngology, Head and Neck Surgery 140, 293-302.

Lin, F.  (2011). Hearing loss and cognition among older adults in the United States.   A: Biological Sciences and Medical Sciences 66 (10), 1131-1136.

Lin, F. & Albert, M. (2014). Hearing loss and dementia – who is listening? Aging and Mental Health 18(6), 671-673.

Lin, F., Ferrucci, L. & Metter, E. (2011). Hearing loss and cognition in the Baltimore Longitudinal Study of Aging. Neuropsychology 25(6), 763-770.

Lin, F., Yaffe, K., & Xia, J. (2013). Hearing loss and cognitive decline in older adults. Journal of the American Medical Association Internal Medicine 173 (4), 293-299.

Lindenberger, U & Baltes, P. (1994). Sensory functioning and intelligence in old age: a strong connection. Psychology of Aging 9, 339-355.

McCoy, S.L., Tun, P.A. & Cox, L.C. (2005). Hearing loss and perceptual effort: downstream effects on older adults’ memory for speech. Quarterly Journal of Experimental Psychology A, 58, 22-33.

Mick, P., Kawachi, I. & Lin, F. (2014). The association between hearing loss and social isolation in older adults. Otolaryngology Head Neck Surgery 150(3), 378-384.

Ohta, R., Carlin, M. & Harmon, B. (1981). Auditory acuity and performance on the mental status questionnaire in the elderly. Journal of the American Geriatric Society 29, 476-478.

Tun, P., McCoy, S. & Wingfield, A. (2009). Aging, hearing acuity and the attentional costs of effortful listening. Psychology and Aging 24(3), 761-766.

Uhlmann, R., Larson, E. & Koepsell, T. (1986). Hearing impairment and cognitive decline in senile dementia of the Alzheimer’s type. Journal of the American Geriatrics Society 34, 207-210.

Uhlmann, R., Larson, E., Rees, T., Koepsell, T. & Duckert, L. (1989). Relationship of hearing impairment to dementia and cognitive dysfunction in older adults. Journal of the American Medical Association 261, 1916-1919.

Valentijn, S., Van Boxtel, M. & Van Hoore, S. (2005). Change in sensory functioning predicts change in cognitive functioning. Results from a 6-year follow-up in the Maastricht Aging Study. Journal of the American Geriatric Society 53, 374-380.

Weinstein, B. & Ventry, I. (1982). Hearing impairment and social isolation in the elderly. Journal of Speech and Hearing Research 25, 593-99.