The Longitudinal Association of Subclinical Hearing Loss With Cognition in the Health, Aging and Body Composition Study

Abstract

ObjectivesTo examine the longitudinal association between subclinical hearing loss (SCHL) and neurocognitive performance.DesignLongitudinal analyses were conducted among 2,110 subjects who underwent audiometric testing in a US multi-centered epidemiologic cohort study. The primary exposure was better ear hearing (pure tone average). SCHL was defined as hearing ≤ 25 dB. The primary outcome was neurocognitive performance, measured by Digit Symbol Substitution Test (DSST), Modified Mini Mental State Examination (3MS), and CLOX1. Linear mixed models were performed to assess the longitudinal association between hearing and cognitive performance, adjusting for covariates. Models were fit among all individuals and among individuals with SCHL only.ResultsAmong 2,110 participants, mean (SD) age was 73.5 (2.9) years; 52.3% were women. Mean (SD) better ear pure tone average was 30.0 (13.1) dB. Mean follow-up was 9.1 years (range 3–16). Among all participants, worse hearing was associated with significantly steeper cognitive decline measured by the DSST [0.054-point/year steeper decrease per 10 dB worse hearing, 95% confidence interval (CI): 0.026–0.082] and 3MS (0.044-point/year steeper decrease per 10 dB worse hearing, CI: 0.026–0.062), but not CLOX1. Among those with SCHL, worse hearing was associated with significantly steeper cognitive performance decline as measured by DSST (0.121-point/year steeper decrease per 10 dB worse hearing, CI: 0.013–0.228), but not CLOX1 or 3MS.ConclusionAmong those with SCHL, worse hearing was associated with steeper cognitive performance declines over time as measured by DSST. The relationship between hearing loss and cognition may begin at earlier levels of hearing loss than previously recognized.

Hearing Aid Usage and Reported Hearing Difficulty in Americans With Subclinical Hearing Loss

“…Second, cochlear synaptopathy (hidden hearing loss) has been recognized as a biological mechanism through which individuals with normal pure tone audiograms may experience subjective difficulty hearing, particularly in background noise (27). Third, SCHL may not be entirely innocuous as studies have shown that worse hearing within this category is associated with worse cognition (20)(21)(22) and worse depressive symptoms (19). The use of the term SCHL is not intended to serve as a new clinical category, but rather as a research construct to study whether hearing levels in the "normal" range are truly innocuous and asymptomatic, as the name normal would imply.…”

“…This calls into question whether those with normal hearing are truly asymptomatic and whether 25 dB is a sensitive enough threshold to define HL. To indicate this uncertainty, we use the term "subclinical" hearing loss (SCHL) for a PTA4 > 0 dB to ≤25 dB, a definition used in previous articles by our group (19)(20)(21)(22). The construct of subclinical hearing loss is not intended to serve as a novel clinical hearing category, but rather to facilitate research into whether minimal levels of hearing loss are symptomatic or associated with morbidity.…”

Cognitive and behavioral effects of hearing loss

“…Ge et al [23] examined both hearing and visual sensory loss; interestingly, only patients with isolated hearing loss or dual sensory loss (both hearing and visual) demonstrated faster rates of cognitive decline, whereas those with only vision loss did not demonstrate a high rate of cognitive decline compared to those with normal sensory function. Chern et al [24 ▪ ] published a longitudinal analysis of 2110 older adult participants in a multicenter cohort study with a mean follow-up of 9.1 years and found that worse hearing in the better ear, including subclinical hearing loss, was associated with a steeper cognitive decline over time. These results were congruent with the findings of an earlier study published by Golub et al [25].…”

Cochlear dysfunction as an early biomarker for cognitive decline in normal hearing and mild hearing loss

“…The World Health Organization defines hearing loss as a 25 dB elevation in hearing thresholds, which are usually measured using perceptual audiometry, estimating a global prevalence of around 500 million people (WHO,2021). Evidence shows that the risk for cognitive decline and all-cause dementia increases with moderate hearing loss (greater than 40 dB HL) (5,6), however, the relationship between hearing loss and cognitive decline could start earlier, including mild hearing loss (in the range between 25 and 40 dB), or even subjects with normal hearing thresholds (<25 dB HL) (7)(8)(9). Importantly, individuals with mild hearing loss (25-40 dB HL) or normal hearing thresholds (<25 dB HL) can have additional hearing impairments that are not detected by conventional audiometry, such as cochlear dead regions, cochlear synaptopathy or hidden hearing loss and central auditory processing disorder (10)(11)(12).…”