Impaired attention predicts motor performance decline in older community-dwellers with normal baseline mobility: results from the Italian Longitudinal Study on Aging (ILSA)

BACKGROUND: Cognitive decline, particularly when executive functions are compromised, may worsen motor performance (MP) decline in the elderly population. We investigated whether a global test, a memory test, and an attention test predicted MP decline in older community-dwellers with normal baseline MP participating in the Italian Longitudinal Study on Aging (ILSA). METHODS: One thousand fifty-two ILSA participants (71.2 +/- 4.8 years old, mean +/- standard deviation [SD], 67% men), with normal baseline MP were reassessed after 3 years using the same MP battery. Participants whose MP score reduction from baseline to follow-up was > 75 percentile were considered to be MP decliners. Global cognition, memory, and attention were assessed using the Mini-Mental State Examination (MMSE), the Babcock Story Recall Test (BSRT), and the Digit Cancellation Test (DCT), respectively. The baseline score on each test was examined as a potential predictor of decline in global MP or in single motor tasks. RESULTS: Baseline scores on the three cognitive tests were worse among the 166 MP decliners, compared with nondecliners. Participants in the lowest quartile of DCT had a > 2-fold higher adjusted risk of declining than did participants in the highest quartile (odds ratio = 2.47, 95% confidence interval, 1.29-4.74). Conversely, MMSE and BSRT scores no longer predicted MP decline after adjustment. Impaired attention strongly predicted the decline in attention-demanding tasks (tandem walking), but also affected routine tasks (walking). CONCLUSIONS: Impairment in a test measuring attention predicts MP decline among older community-dwellers with normal baseline MP. This finding is consistent with the hypothesis that attentional and executive dysfunction is a major determinant of mobility disability in elderly persons.