Central Auditory Dysfunction, Cognitive Dysfunction, and Dementia in Older People

Abstract

OBJECTIVES: To determine in older people the relation between auditory dysfunction and cognitive dysfunction, and if central auditory test abnormalities predict the onset of clinical dementia or cognitive decline. DESIGN: Prospective population-based cohort study. SETTING: Framingham Heart Study outpatient biennial examinations 18 and 21. PARTICIPANTS: Members of the Framingham Heart Study cohort with normal findings from cognitive screening tests at biennial examination 18. MEASUREMENTS: Peripheral audiometric thresholds and word recognition in quiet; Synthetic Sentence Identification with Ipsilateral Competing Message (SSI-ICM); Mini-Mental State Examination; and detailed neuropsychological testing of subjects with abnormal findings from the Mini-Mental State Examination. Relative risk of dementia was determined using age-adjusted Cox proportional hazards regression models. RESULTS: Hearing loss significantly lowered performance on the verbal parts of the Mini-Mental State Examination. The relative risk of subsequent clinical dementia or cognitive decline was 6 in subjects with very poor scores (< 50%) in one ear on the SSI-ICM (P = .02); the relative risk was 12.5 if the poor scores were present in both ears (P = .001). CONCLUSIONS: Central auditory dysfunction precedes senile dementia in a significant number of cases and may be an early marker for senile dementia. Hearing tests should be included in the evaluation of persons older than 60 years and in those suspected of having cognitive dysfunction.