Measurement of vibrotactile thresholds of normal children

Abstract

In this study, the vibrotactile thresholds of children (ages between 8 and 11) weremeasured at several frequencies, and compared to the vibrotactile thresholds of adults(ages between 21 and 27) at 40 Hz and 250 Hz. Also, the thresholds of Non-Pacinian I(NPI) channel of children were measured at 40 Hz.Since Pacinian (P) channel and NPI channel have similar thresholds at 40 Hz, a forward-masking procedure was used to elevate the threshold of P channel. Results werecompared to NPI channel thresholds of adults at 40 Hz. To enable comparison withpopulation models of mechanoreceptive fibers in the literature, the studies were performedusing the terminal phalanx of middle finger and no contactor surround was used. Thresholds were measured using a two-interval forced-choice paradigm, in order to ensurethat the measurements were independent of the subject̕s criterion.No statistically significant differences were found between the absolute thresholdsof children and adults at 40 Hz and 250 Hz. For NPI channel thresholds, children and adults̕ data were found to be marginally different. However, more data are needed toreach a firm conclusion. Moreover, the masking functions of children at 250 Hz wereobtained. The threshold shifts increased as masking stimulus levels were increased. Theresults were discussed in relation to previous studies in literature.|Keywords: Vibrotactile sensitivity, psychophysical channels, aging.