Sensory impairment and cognitive functioning in oldest-old subjects: the Leiden 85+ Study

Because studies on the association of sensory impairment (both hearing and visual impairment) and cognitive functioning in elderly persons yielded conflicting results, the authors explored this association within the Leiden 85+ Study.

Within this population-based study of 459 participants aged 85+ years, hearing impairment was measured by audiometry and visual impairment by a visual acuity chart, both under standardized conditions. The Mini-Mental State Exam (MMSE) assessed global cognitive functioning. In participants with MMSE scores >18, the authors further assessed memory (Word-Learning Test, Immediate and Delayed Recall) and cognitive speed (by Stroop Test, Letter-Digit Coding test).

Both hearing impairment (prevalence: 85%) and visual impairment (prevalence: 59%) were associated with lower scores on the MMSE. Increasing visual impairment was associated with poorer scores on memory and cognitive speed, as measured with visually presented cognitive tests. In contrast, there was no association between hearing impairment and memory and cognitive speed.

In elderly people, cognitive functioning as assessed by visual cognitive tests relates to visual impairment but not to hearing impairment. The authors therefore assume that the association between sensory impairment and cognitive functioning is, at least partly, based on practical disadvantages of elderly persons with sensory impairment during cognitive assessments.