Vibrotactile thresholds at the fingertip, volar forearm, large toe, and heel

Abstract

Published as: Vibrotactile thresholds at the fingertip, volar forearm, large toe and heel Morioka, M., Whitehouse, D. J. & Griffin, M. J. 2008 In : Somatosensory & Motor Research. 25, 2, p. 101-112. 2 AbstractThresholds for the perception of vibration vary with location on the body due to the organisation of tactile channels in hairy and non-hairy skin, and variations in receptor density. This study determined vibration thresholds at four locations on the body with two different contactors so as to assist the identification of the tactile channel determining the threshold at each location. Vibrotactile thresholds at six frequencies from 8 to 250 Hz were measured on the distal phalanx of the index finger, the volar forearm, the large toe, and the heel with two contactors: (i) a 1-mm diameter circular probe with a 1-mm gap to a fixed circular surround (i.e. 7.1-mm 2 excitation area), and (ii) a 6-mm diameter circular probe with a 2-mm gap to a fixed circular surround (i.e. 79-mm 2 excitation area). At all frequencies and with both contactors, thresholds on the fingertip were lower than thresholds on the volar forearm, the large toe, and the heel, consistent with a greater density of mechanoreceptors at the fingertip. Thresholds with the larger contactor were lower than thresholds with the smaller contactor on the fingertip at high frequencies (63, 125 and 250 Hz), on the large toe (except at 250 Hz), on the heel (at all frequencies), and on the volar forearm at 250 Hz. It is concluded that at least two tactile channels (Pacinian from 63 to 250 Hz, and non-Pacinian from 8 to 31.5 Hz) determined vibrotactile thresholds at the fingertip, whereas non-Pacinian channels had a dominant influence on vibrotactile thresholds at the volar forearm. The role of Pacinian and non-Pacinian channels could not be confirmed at the large toe or the heel despite some evidence of spatial summation.Published as: Vibrotactile thresholds at the fingertip, volar forearm, large toe and heel Morioka, M., Whitehouse, D.

Relation between vibrotactile perception thresholds and reductions in finger blood flow induced by vibration of the hand at frequencies in the range 8–250 Hz

“…Thresholds at the high frequencies (63, 125 and 250 Hz) were generally not correlated with thresholds at the low frequencies (8, 16 and 31.5 Hz), indicating that different channels mediated thresholds at low and high frequencies in most subjects. This is consistent with other studies of perception thresholds using the same apparatus and vibration applied to the fingertip (Morioka and Griffin, 2005;Morioka et al, 2008).…”

“…The most sensitive channel depends on the frequency of the vibration, the contact conditions, the location on the hand, and some other factors. The Pacinian (P) channel, mediated by Pacinian corpuscles (also called FA II units), has the lowest threshold at frequencies greater than about 40 Hz when using a 6-mm vibrating contactor (Morioka and Griffin, 2005;Morioka, et al, 2008), and exhibits both spatial and temporal summation: reduced thresholds with increased area of excitation and increased duration of vibration (Verrillo 1962(Verrillo , 1963. Of the three non-Pacinian channels, the NPI channel often determines thresholds at frequencies between 4 and 40 Hz and is associated with Meissner corpuscles (FA I units), whereas the NPII and NPIII channels are associated with slow adapting fibres and have been identified from the results of psychophysical experiments (Capraro et al, 1979, Bolanowski et al, 1988, Verrillo et al, 2002.…”

Mechanical and Psychophysical Studies of Surface Wave Propagation during Vibrotactile Stimulation

“…Larger stimuli or larger contact areas were found to produce significantly smaller threshold values signifying higher sensitivity Gescheider et al, 1994;Morioka et al, 2008). Skin temperature was also found to significantly affect sensitivity to vibration, with warmer skin temperature tending to lower the amplitude threshold, and cold increasing it .…”

“…Threshold values can also vary with body location, due to variations in innervation density. When comparing threshold values over the frequency range of 8-250 Hz on the fingertip, volar forearm, large toe, and heel, a significant effect of location was found; the fingertip had the lowest average threshold values, followed by the big toe, the heel, and lastly the volar forearm which had the highest thresholds (Morioka et al, 2008). These results follow the same ranking of body part sensitivity as found with two-point gap thresholds (Gibson & Craig, 2005;Stevens & Choo, 1996), and again demonstrates the improved sensing ability of glabrous as compared to hairy skin.…”

“…Much research has gone into examining the sensory properties and capabilities of skin Johansson & Vallbo, 1979;Konietzny & Hensel, 1977;Morioka et al, 2008;Stevens & Choo, 1996), as well as looking at the physical dynamic behavior of skin in response to an applied dynamic stimulus (Boyer et al, 2007;Franke et al, 1951;Jones & Held, 2008;Li et al, 2011;Liang & Boppart, 2010). The goal of the present research is to examine how the skin responds to vibrotactile stimulation with the objective of determining what the optimal configuration of vibrotactile displays is at different locations on the body, when they are used for spatial cuing.…”