THE EFFECTS OF AGING ON INFORMATION-PROCESSING CHANNELS IN THE SENSE OF TOUCH .2. TEMPORAL SUMMATION IN THE P-CHANNEL

Thresholds for detecting 250-Hz vibrotactile signals of variable durat ion applied to the thenar eminence of the hand were measured in 16 sub jects ranging in age from 19 to 81 years. Detection thresholds were hi gher in older than in younger subjects. Correlation coefficients for t he relation between threshold and age ranged from 0.94 to 0.96, depend ing on signal duration. In addition, the amount of temporal summation was negatively correlated with age. Both the elevated detection thresh olds and the reduced amount of temporal summation in elderly subjects may be partially due to the decrease in the number of Pacinian corpusc les in the hand that occurs with aging. Another factor that could be r esponsible for reduced temporal summation in older as compared to youn ger subjects is impairment of the temporal integrator.