Self-reported hearing loss is associated with faster cognitive and functional decline but not diagnostic conversion in the ADNI cohort

Abstract

Introduction: Hearing loss is identified as one of the largest modifiable risk factors for cognitive impairment and dementia. Studies evaluating this relationship have yielded mixed results.

Methods: We investigated the longitudinal relationship between self-reported hearing loss and cognitive/functional performance in 695 cognitively normal (CN) and 941 participants with mild cognitive impairment (MCI) enrolled in the Alzheimer's Disease Neuroimaging Initiative.

Results: Within CN participants with hearing loss, there was a significantly greater rate of cognitive decline per modified preclinical Alzheimer's cognitive composite. Within both CN and MCI participants with hearing loss, there was a significantly greater rate of functional decline per the functional activities questionnaire (FAQ). In CN and MCI participants, hearing loss did not significantly contribute to the risk of progression to a more impaired diagnosis.

Discussion: These results confirm previous studies demonstrating a significant longitudinal association between self-reported hearing loss and cognition/function but do not demonstrate an increased risk of conversion to a more impaired diagnosis.

Clinical trial registration information: NCT00106899 (ADNI: Alzheimer's Disease Neuroimaging Initiative, clinicaltrials.gov), NCT01078636 (ADNI-GO: Alzheimer's Disease Neuroimaging Initiative Grand Opportunity, clinicaltrials.gov), NCT01231971 (ADNI2: Alzheimer's Disease Neuroimaging Initiative 2, clinicaltrials.gov), NCT02854033 (ADNI3: Alzheimer's Disease Neuroimaging Initiative 3, clinicaltrials.gov).

Highlights: Hearing loss is a potential modifiable risk factor for dementia. We assessed the effect of self-reported hearing loss on cognition and function in the ADNI cohort. Hearing loss contributes to significantly faster cognitive and functional decline. Hearing loss was not associated with conversion to a more impaired diagnosis.

Keywords: cognition; conversion; hearing loss; memory; neuropsychological testing.

FIGURE 1

Change in cognition and function over time for participants with and without hearing loss. (A) Change in adjusted mPACC with 95% CI over time in participants with a baseline diagnosis of CN. (B) Change in adjusted ADAS‐Cog‐11 with 95% CI over time in participants with a baseline diagnosis of MCI. (C) Change in adjusted FAQ with 95% CI over time in participants with a baseline CN diagnosis. (D) Change in adjusted FAQ with 95% CI over time in participants with a baseline MCI diagnosis. Repeated‐measures linear mixed models with mPACC (A), ADAS‐Cog‐11 (B), or FAQ (C, D) as the outcome variable and the interaction of hearing loss and time as the main explanatory variable were used to determine the relationship between hearing loss, cognition, and time. Age, sex, education, APOE ɛ4 copy number, baseline ADAS‐Cog‐11, and a random intercept were included as covariates. Adjusted mPACC, ADAS‐Cog‐11, and FAQ scores represent an estimated mean when sex = male, APOE ɛ4 copy number = 2, baseline ADAS‐Cog‐11 = 0, age = 0, and education = 0. PEs and p values are reported for the main explanatory variable of the hearing loss×time interaction term from the original linear mixed models. ADAS‐Cog‐11, Alzheimer's Disease Assessment Scale‐Cognitive Subscore; CI, confidence interval; CN, cognitively normal; FAQ, Functional Activities Questionnaire; MCI, mild cognitive impairment; mPACC, modified Preclinical Alzheimer's Cognitive Composite; APOE, apolipoprotein E; PE, parameter estimate.

FIGURE 2

Risk of hearing loss on conversion to a more impaired diagnostic group. Survival curves were generated using the Kaplan–Meier method. Survival curves were generated for all conversion events (A; CN to MCI or AD dementia and MCI to AD dementia), CN to MCI or AD‐dementia conversion events only (B), and MCI to AD dementia conversion events only (C). Orange lines represent participants with hearing loss, and blue lines represent participants without hearing loss. χ² values and associated p values were derived using log‐rank (Mantel–Cox) test of equality of survival distributions. AD, Alzheimer's disease; ADAS‐Cog‐11, Alzheimer's Disease Assessment Scale‐Cognitive Subscale; CN, cognitively normal; MCI, mild cognitive impairment.