Subjective hearing loss is not associated with an increased risk of Alzheimer's disease dementia

Abstract

Hearing loss is a risk-factor for dementia but the reasons for this are unclear. Subjective hearing loss is related to increased future dementia risk, however, this metric has not been previously examined with cognitive, neuroimaging and biochemical measures that are relevant to Alzheimer's disease. We assessed Cognitively Normal and Mild Cognitively Impaired participants from the Alzheimer's Disease Neuroimaging Initiative with subjective hearing loss to examine if they had faster decline in episodic memory scores, hippocampal volume and greater pTau positivity. The likelihood of a dementia diagnosis in hearing impaired participants over a 5-year period was also assessed. There were no statistically significant differences between the hearing subgroups over a 5-year period nor were there in conversions to a dementia diagnosis. Objective hearing loss metrics may provide a more reliable link between hearing loss and dementia risk.

Keywords: Alzheimer's disease; Cognition; Dementia; Hearing loss; Neuroimaging.

Fig. 1

A flowchart showing the number of cognitively normal participants that remained with that diagnosis at 12-month intervals. The different rows indicate the total number of participants that completed neuropsychological, neuroimaging or CSF biomarker evaluation. The number of hearing unimpaired participants are indicated with a blue background and those with self-reported hearing impairment have a red background. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

A flowchart showing the number of participants with MCI remained with that diagnosis at 12-month intervals. The different rows indicate the total number of participants that completed neuropsychological, neuroimaging or CSF biomarker evaluation. The number of hearing unimpaired participants are indicated with a blue background and those with self-reported hearing impairment have a red background. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3

A flowchart showing the number of participants with MCI that converted to a diagnosis of AD dementia at 12-month intervals. The different rows indicate the total number of participants that completed neuropsychological, neuroimaging or CSF biomarker evaluation. The number of hearing unimpaired participants are indicated with a blue background and those with self-reported hearing impairment have a red background. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4

Cox Proportional Hazard (CPH) analysis for conversion from MCI to AD Dementia. The image on the left shows the hazard ratios estimated by the CPH model for various covariates. APOE4 status has the largest impact on conversion to dementia, followed by age. The image on the right shows adjusted survival curves for people with (HL) (blue line) and without (HN) (red line) hearing loss. There is no significant impact on dementia conversion based on hearing status. CI – Confidence Interval. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)