Abstract and Introduction
Abstract
Background/Objectives: To better understand the role of sensory loss as a potentially modifiable risk factor for cognitive decline, this study examined cognitive decline in relation to single modality hearing or vision loss and dual sensory loss.
Design: Longitudinal secondary data analysis.
Setting: The Health and Retirement Study (HRS) and its supplement: The Aging, Demographics, and Memory Study (ADAMS).
Participants: Individuals aged 73 and older (N = 295).
Measurements: Hearing loss was defined by an inability to hear sounds of 25 dB at frequencies between 0.5 and 4.0 kHz in either ear. Vision loss was defined as having corrected binocular vision worse than 20/40. Dual sensory loss was defined as having both hearing and vision loss. We used one time point of hearing and vision data objectively measured in ADAMS Wave C (June 2006–May 2008) and five waves of cognitive function data measured by the HRS version of the Telephone Interview for Cognitive Status in HRS (2006–2014). Multilevel mixed models were used.
Results: Among the participants, 271 completed a hearing assessment and 120 had hearing loss; 292 completed a vision assessment and 115 had vision loss; 52 had dual sensory loss. Older adults with hearing loss had a significantly faster rate of cognitive decline as they aged compared to those with normal hearing (β = −0.16, P < .05). No significant association was found between vision loss and the rate of cognitive decline (β = −0.06, P = .41). Older adults who had dual sensory loss likewise had a significantly faster rate of cognitive decline as they age (β = −0.23, P < .05) compared to those with no sensory loss.
Conclusion: Older adults with hearing loss and dual sensory loss have faster rates of cognitive decline than those with normal sensory function.
Introduction
Cognitive decline, ranging from mild cognitive impairment to Alzheimer's disease and related dementias (ADRD), presents challenges in older adults' daily lives.[1–3] Cognitive impairment and ADRD have become a major public health and social concern as a result of global aging.[4,5] ADRD is projected to affect more than 152 million individuals globally by the year 2050.[6] Multiple countries, including the United States, have identified preventing ADRD as an important public health priority, indicating the need for programs that can help prevent cognitive decline in the populations at risk.[7] Identifying and understanding modifiable risk factors for cognitive decline will contribute to developing effective interventions to better preserve cognitive function in the aging population.
Hearing loss and vision loss have drawn increasing attention as potentially modifiable risk factors for cognitive decline and ADRD. The prevalence of both hearing loss and vision loss among older adults is projected to increase over the next few decades.[8,9] Among older adults aged 70 years or older, more than 60% are affected by hearing loss,[8] and about 40% are affected by vision loss.[10,11] Accumulating evidence suggests that both hearing and vision loss can be independently associated with worse cognitive function or faster rate of cognitive decline.[12–15] However, most of this evidence is from cross-sectional studies. Far fewer longitudinal studies have examined the relationship between sensory loss and cognitive decline, and the findings have been inconsistent. Some longitudinal studies have found significant associations between sensory loss and cognitive decline,[16–20] but others have not.[12,13] The inconsistencies in previous study findings may be related to methodological differences, including different approaches in measuring sensory loss (subjective or objective), different measures of cognitive function, and variable lengths of follow-up. In addition, the presence of dual sensory loss may contribute to the discrepant findings.[21] The prevalence of dual sensory loss (i.e., both hearing and vision) has been reported as high as 22.5% among adults over age 70.[22,23] Dual sensory loss may have additional deleterious effects on cognitive decline. However, to date, of the studies that have examined the associations between dual sensory loss and cognitive decline, few have been longitudinal or have used objective measures of sensory function, and studies have yielded inconsistent findings.[13–15,24] Therefore, studies using robust measures of dual sensory loss and cognitive function should help to better delineate the relationship between sensory loss and cognitive change over time.
To better understand the roles of hearing loss, vision loss, and dual sensory loss as risk factors for cognitive decline, this study aims to examine (1) the associations between single modality hearing or vision loss and cognitive decline; and (2) the associations between dual sensory loss and cognitive decline as people grow older.
J Am Geriatr Soc. 2021;69(3):644-650. © 2021 Blackwell Publishing
