Quantitative vibration perception testing in elderly people: an assessment of variability.

The variability of vibration perception threshold measured by the Biothesiometer for three consecutive readings on a single occasion and 18 sequential readings over 7 days was assessed in 20 elderly convalescent subjects. The coefficient of variation for three consecutive readings at the great toe was high [right great toe: median (range) 15 (6-260%]. The median coefficients of variation for sequential readings were higher than those for consecutive readings at both toes [right great toe: median (range) 26 (5-71)% versus 15 (6-26)%, p = 0.0001]. Thus quantitative tests of sensory function are not reliable in elderly people, even when the subjects have no acute medical problem. Screening for neuropathy in elderly patients should probably rely on clinical examination or electrophysiological tests.