THE EFFECTS OF AGING ON INFORMATION-PROCESSING CHANNELS IN THE SENSE OF TOUCH .1. ABSOLUTE SENSITIVITY

Thresholds for detecting vibrotactile signals of variable frequency ap plied to the thenar eminence of the hand by small and large contactors were measured in subjects ranging in age from 10 to 89 years. Thresho lds were found to increase as a function of age, but the rate of incre ase was greater after than before the age of 65 years. The rate of los s of vibrotactile sensitivity was substantially greater in the P chann el (mediated by Pacinian corpuscles) than in the NP I channel (mediate d by rapidly adapting fibers), the NP II channel (mediated by slowly a dapting type II fibers), or the NP III channel (mediated by slowly ada pting type I fibers). Women were frequently found to have greater sens itivity than men.