Correlates of vibrotactile thresholds in men of different ages.

As a part of a larger gerontological research project vibrotactile thresholds on the inner malleolus of the ankle were studied in 355 men aged 31-35, 51-55 and 71-75 years. The groups studied were random samples of men living in the town of Jyväskylä in Finland in the year 1981. The thresholds were assessed at three frequencies: 50 Hz, 100 Hz and 250 Hz. The thresholds were associated with age at all frequencies, the means of the threshold values being significantly higher in the older age groups. Within the age groups the thresholds correlated positively with height. In addition, reaction and movement time, leg extension velocity, and postural sway were associated with the thresholds. Neither general health status nor occupational or educational background, or living habits had significant influence on the thresholds within the age groups. The results suggest that the elevation of vibrotactile thresholds is an inherent manifestation of aging in the nervous system. In addition to age, the height of the respondents is among the factors that should be taken into account when interindividual comparisons are made, if the measurement is on distal parts of the body.