The prevalence of peripheral and central hearing impairment and its relation to cognition in older adults

Age-related hearing loss (ARHL) and dementia are two highly prevalent conditions in the adult population. Recent studies have suggested that hearing loss is independently associated with poorer cognitive functioning. The aim of this study was to evaluate the prevalence of ARHL and cognitive impairment in a large sample of subjects older than 65 years and to correlate hearing function with cognitive function. A total of 488 subjects older than 65 years (mean age 72.8 years) participating in the Great Age Study underwent a complete audiological, neurological and neuropsychological evaluation as part of a multidisciplinary assessment. The prevalence of a hearing loss greater than 25 dB HL was 64.1%, of Central Auditory Processing Disorder (CAPD) was 14.3 and 25.3% of the subjects reported a hearing handicap as reported on the Hearing Handicap Inventory for the Elderly Screening Version questionnaire. Multiple logistic regression analysis corrected for gender, age and education duration showed that mild cognitive impairment (MCI) was significantly associated with hearing impairment (CAPD and hearing threshold; odds ratio 1.6, p = 0.05) and that Alzheimer's disease (AD) was significantly associated with CAPD (odds ratio 4.2, p = 0.05). Given that up to 80% of patients affected by MCI convert to AD, adding auditory tests to a screening cognitive battery might have value in the early diagnosis of cognitive decline.