The effects of aging on information-processing channels in the sense of touch: II. Temporal summation in the P channel.

Thresholds for detecting 250-Hz vibrotactile signals of variable duration applied to the thenar eminence of the hand were measured in 16 subjects ranging in age from 19 to 81 years. Detection thresholds were higher in older than in younger subjects. Correlation coefficients for the relation between threshold and age ranged from 0.94 to 0.96, depending on signal duration. In addition, the amount of temporal summation was negatively correlated with age. Both the elevated detection thresholds and the reduced amount of temporal summation in elderly subjects may be partially due to the decrease in the number of Pacinian corpuscles in the hand that occurs with aging. Another factor that could be responsible for reduced temporal summation in older as compared to younger subjects is impairment of the temporal integrator.