In a recent US epidemiological study, a relationship was found between the severity of hearing loss and cognitive decline in 1, patients aged 70 to 79 years, with follow-up over six years Lin et al. Nonetheless, there is little data on long-term decline in elderly people with hearing loss or on the possible effect of rehabilitation of these impairments through use of hearing aids.
Thanks to the very long-term data now available from the PAQUID epidemiological study, and since data on hearing disorders were collected at the enrollment visit, we were able to analyze the effect of hearing impairment, with or without hearing assistance, on changes in cognitive functions in a study cohort with follow-up over 25 years. This article sums up the results of this recently published study Amieva et al. Initiated in the early s, the PAQUID cohort included 3, participants aged 65 years and over, living at home, in the Gironde and Dordogne departments of Southwest France, on the basis of random selection from lists of voters.
About every two years, study participants had an appointment with a psychologist who assessed their state of health on the basis of various questionnaires, scales, and tests concerning their physical, functional, psychological and cognitive health. A neurologist or geriatric physician also visited the subjects if dementia was suspected.
Participants were thus followed-up for 25 years, making the PAQUID cohort one of the epidemiological studies in geriatrics with the longest follow-up periods worldwide. For this study, the sample included 3, subjects, after exclusion of people with existing dementia, i.
At this initial visit, two questions specifically concerned hearing impairment and use of hearing aids. Of the 3, participants answering this question, 2, reported no problematic hearing loss, 1, reported moderate impairment, particularly when following a conversation with several speakers or in a noisy environment, and reported major impairment.
Among those reporting moderate to major impairment 1, subjects in all , used a hearing aid and 1, did not. The test has 30 points that evaluate memory, attention, calculation abilities, language, and visuoconstruction abilities. Changes in this test score over the 25 years of cohort follow-up were modelled using mixed linear regression. Three regression models were used in succession:.
In the first statistical model, results showed that over the 25 years of follow-up, people with hearing loss had a statistically significant greater decline in MMSE test scores than people with no hearing impairment. However, the second model showed that only the group of subjects without hearing aids had this statistical greater decline than the control group, in other words people with no hearing impairment.
Changes in MMSE scores for people with hearing impairment and who used hearing aids were not different from those of the control group. In the third statistical model, in which psychosocial variables were considered, the increased decline related to hearing loss was no longer statistically significant, including in people who did not wear hearing aids.
This study supports the findings reported by Lin et al. In this way, it confirms that there is accelerated cognitive decline in elderly people with hearing impairment.
There does however not appear to be a direct relationship between hearing loss and cognitive decline.
Many studies have demonstrated the relationship between hearing loss and depressive symptoms, and decreased leisure activities and social interactions.
These results are in line with the results of our study because when psychosocial variables are considered, the greater decline related to hearing loss was no longer statistically significant, including in people who do not use hearing aids.
This result clearly shows that the relationship between hearing loss and cognitive decline can be explained by social isolation and depressed mood, which develop gradually in elderly people with hearing loss. Accelerated cognitive decline in the elderly with hearing impairment therefore appears to be preventable.
Our study has shown that cognitive decline in people with hearing loss using hearing aids is not different from that of subjects with no hearing loss. This result has not been found until now.
The prevalence of probable Alzheimer's disease decreased dramatically as educational level increased, lung 5. The relationship between dementia and educational level is still controversial in the literature. This suggests that educational level is indeed an important correlate of dementia in the French elderly community. At 65 years of age, a person's dementia-free life expectancy is Although dementia prevalence increases with age, if the prevalence is adjusted for mortality, the largest number of persons with dementia are in their early eighties.
At each age women have a higher dementia-free life expectancy. Trends in dementia-free life expectancy are similar to those found in disability-free life expectancy. Because the dementia prevalence rates used in this estimate resemble a general model derived from meta-analysis, it can be assumed that similar results will be found in other Western countries with similar mortality rates.
Full text is available as a scanned copy of the original print version. Get a printable copy PDF file of the complete article 2. Links to PubMed are also available for Selected References. These references are in PubMed. This may not be the complete list of references from this article. National Center for Biotechnology Information , U. Am J Public Health.
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