Betz, Joshua

AbstractBackgroundHearing impairment is associated with cognitive decline but whether it is a cause or marker is unknown. We investigated the association of hearing impairment with brain volumes and 8‐year cognitive decline. Because the superior temporal gyrus (STG) is the location of the primary auditory cortex, we stratified results by STG volume to investigate if the association of hearing and cognition differed among participants with and without evidence of possible hearing‐related brain atrophy.MethodWe used data from 1195 community‐dwelling adults (72‐94 years, 61% female, 36% black) from the Atherosclerosis Risk in Communities Study. A composite cognitive score was created from 10 neuropsychological tests administered at 3 study visits spanning 8 years (2011‐13 to 2018‐19). Brain volumes were calculated from structural magnetic resonance imaging scans for 6 regions of interest. Pure tone air conduction hearing thresholds (frequencies 0.5‐4 kHz) were obtained in 2016‐17 and averaged, with better‐ear hearing impairment defined as an average >25 dB. Multivariable‐adjusted linear regression was used to estimate cross‐sectional differences in standardized brain volumes, adjusting for intracranial volume, demographic and clinical covariates. We estimated differences in annual rates of cognitive change by hearing impairment status adjusting for demographic and clinical covariates using linear mixed models; results were stratified by intracranial volume‐adjusted STG volume (below vs. equal to or greater than the median value).ResultThe mean STG volume difference comparing hearing impairment to normal hearing was ‐0.121 standard deviations (SD) (95% CI: ‐0.213, ‐0.028). Overall, the difference in the rate of cognitive decline associated with hearing impairment was ‐0.014 SD (‐0.023, ‐0.005). Hearing was more strongly associated with cognitive decline among participants with smaller STG volumes; rate difference, ‐0.014 SD (‐0.027, ‐0.002) compared to ‐0.008 (‐0.022, 0.006) for participants with larger STG volumes.ConclusionHearing impairment was associated with smaller brain volumes in the primary auditory region, but not with other regions. Our stratified analysis suggests that hearing treatment might be an important possible strategy to delay cognitive decline, even among participants with hearing‐related brain atrophy. Furthermore, the adverse cognitive effects of hearing impairment could potentially be mitigated if early hearing treatment can prevent STG atrophy.

AbstractBackgroundAlthough both age‐related and highly prevalent, little is known regarding the prevalence of hearing loss among persons with dementia (PwD). Current understanding is based on convenience samples primarily from specialized memory clinics. The Atherosclerosis Risk in Communities Neurocognitive Study (ARIC‐NCS) is a large, prospective study of a population‐based cohort from 4 U.S. community sites with audiometric and neurocognitive testing and bi‐racial representation. We examined the prevalence of hearing loss and hearing aid use among older adults with cognitive impairment and whether cognitive status influences hearing aid use.MethodWe analyzed audiometric and hearing care data from ARIC‐NCS Visit 6 (2016‐2018). Participants underwent a full neurocognitive battery and audiometric evaluation at Visit 6. Participants with complete audiometric data and an adjudicated diagnosis of cognitively normal, mild cognitive impairment (MCI), or dementia were included in the analytical cohort (N=3,385). Differences in participant characteristics by cognitive status were descriptively compared using Chi‐square tests or one‐way ANOVAs. We performed a series of logistic regression models to estimate the odds of hearing aid non‐use by cognitive status.ResultPrevalence of hearing loss was greater with increasing cognitive impairment (cognitively normal:64.7%; MCI:71.3%; dementia:83.3%). Prevalence of hearing aid use among those with hearing loss and cognitive impairment varied by race (African Americans 7.2%; whites 32.8%). In a multivariable‐adjusted model, cognitive impairment was independently associated with higher odds of non‐use of hearing aids (MCI odds ratio (OR):1.4 (95%CI:1.0‐1.8); dementia OR:1.8 (95%CI:1.2‐2.9) versus cognitively normal). The strongest risk factor for non‐use of hearing aids was race, where African Americans have almost a 5 times higher odds of not using hearing aids compared to whites (95% CI:2.9‐7.4).ConclusionHearing loss is highly prevalent but vastly untreated among older adults with cognitive impairment, particularly African Americans, and cognitive impairment is independently associated with hearing aid use. These estimates are some of the first population‐based estimates of audiometric hearing loss among diverse older adults with adjudicated diagnoses of MCI or dementia. With increased calls to address ethnic/racial disparities, we must include hearing loss, as one of the most common co‐morbidities, in order to optimize health and well‐being among all PwD.