Introduction: To assess the association between sensory and cognitive function, and the potential influence of visual function on cognitive function assessment, in a sample of clients accessing aged care services.
Materials and methods: We recruited 260 non-institutionalised, frail, older individuals who sought aged care services. Visual acuity was assessed using a LogMAR chart and hearing function was measured using a portable pure-tone air conduction audiometer. Visual impairment was defined as visual acuity (VA) <6/12 (<39 letters read correctly in the better eye), moderate-to-severe hearing impairment as hearing thresholds >40 decibels (better ear) and cognitive impairment as Mini-Mental State Examination (MMSE) score <24.
Results: Vision and hearing assessments were randomly performed in 168 and 164 aged care clients, respectively. Visual acuity correlated weakly with MMSE scores, either including (r = 0.27, P <0.001) or excluding (r = 0.21, P = 0.006) vision-related MMSE items. After partialling out the effect of age, the association remained (r = 0.23, P = 0.013 including, or r = 0.18, P = 0.044 excluding vision-related items). No correlation was found between MMSE scores and hearing thresholds (r = -0.07, P = 0.375). After adjusting for age, sex and stroke, mean MMSE scores were lower in persons with visual impairment than those with normal vision (25.2 + 0.5 versus 26.8 + 0.4 including, or 18.2 + 0.5 versus 19.2 + 0.3 excluding vision-related items), but were similar between subjects with none or mild and those with moderate-to-severe hearing loss (26.3 + 0.4 versus 26.0 + 0.4).
Conclusions: In this study sample, visual and cognitive functions were modestly associated, after excluding the influence of visual impairment on the MMSE assessment and adjusting for age. Hearing thresholds were not found to be associated with cognitive function.