Age-Related Hearing Loss, Neuropsychological Performance, and Incident Dementia in Older Adults.

BACKGROUND

Age-related hearing loss (HL) has been associated with dementia, though the neurocognitive profile of individuals with HL is poorly understood.

OBJECTIVE

To characterize the neurocognitive profile of HL.

METHODS

N = 8,529 participants from the National Alzheimer's Coordinating Center ≥60 years and free of cognitive impairment who were characterized as Untreated-, Treated-, or No HL. Outcomes included executive function (Trail Making Test [TMT] Part B), episodic memory (Immediate/Delayed Recall), language fluency (Vegetables, Boston Naming Test), and conversion to dementia. Regression models were fit to examine associations between HL and neurocognitive performance at baseline. Cox proportional hazards models examined the links between HL, neurocognitive scores, and development of dementia over follow-up.

RESULTS

At baseline, those with Untreated HL (versus No HL) had worse neurocognitive performance per standardized difference on executive function (TMT Part B [mean difference = 0.05 (95% CI 0.00, 0.10)]) and language fluency (Vegetables [mean difference = -0.07 (95% CI -0.14, -0.01)], Boston Naming Test [mean difference = -0.07 (95% CI -0.13, -0.01)]). No differences in these neurocognitive performance scores were demonstrated between Treated HL and No HL groups other than MMSE [mean difference = -0.06 (95% CI -0.12, 0.00)]. Through follow-up, executive dysfunction differed by hearing group (χ2(2) = 46.08, p < 0.0001) and was present among 39.12% in No HL, 44.85% in Untreated HL, and 49.40% in Treated HL. Worse performance across all cognitive domains predicted incident dementia.

CONCLUSION

The observed association between Untreated HL and lower cognitive ability that improved when hearing aids were worn may reflect an inability to hear the test instructions. Future studies using cognitive assessments validated for use in HL are needed to evaluate the neuropsychological profile of HL and identify individuals at risk for dementia.