Motor correlates of finger tapping variability in subjective memory complaints, mild cognitive impairment and probable Alzheimer's disease.

Background: Variability of finger tapping speeds, especially in the non-dominant hand, has been reported in individuals with amnestic mild cognitive impairment (MCI-A) and dementia of the Alzheimer's type (AD). An explanation of this finding, however, has not appeared.

Objective: The aim of this study was to investigate possible motor correlates of finger tapping variability in normal older healthy controls (HC), persons with subjective memory complaints (SMC), MCI-A and probable AD.