Hearing and cognition in the elderly. New findings and a review of the literature.

The purpose of this study was to determine the relationship between hearing status and cognitive status initially and at 5-year follow-up in a cohort of healthy elderly men and women and to relate the results to published reports on this topic. Volunteers older than 60 years with no major illnesses and taking no long-term prescription medications were examined. Baseline testing of hearing and cognition was performed in 224 subjects; 112 subjects underwent cognitive testing at 5-year follow-up. Hearing was measured by the Speech Perception in Noise test; cognition was measured by two parts of the Wechsler Memory Scale and by the Jacobs Cognitive Screening Test, an oral screening instrument. At baseline there were small correlations between hearing acuity and memory scores, but these disappeared after adjustment for age and gender. Analysis of follow-up memory and cognitive screening test scores in relation to baseline hearing ability showed no correlation between hearing at entry and cognitive function at 5 years. In addition, baseline hearing level did not predict change in memory or cognitive screening test scores during the follow-up period. The power of the study was 90% to detect a correlation of .30 between measures of hearing and cognition. There was no evidence for a major effect of hearing acuity on cognitive function over time in this group of healthy elderly. Review of published studies suggests that hearing ability is related to cognitive status in demented subjects, but there is little to suggest that in the normal elderly, hearing impairment leads to cognitive decline.