Vibrotactile and thermal perception and its relation to finger skin thickness

Abstract

Objective: Quantitative measurements of vibrotactile and thermotactile perception thresholds (VPT and TPT, respectively) rely on responses from sensory receptors in the skin when mechanical or thermal stimuli are applied to the skin. The objective was to examine if there is a relation between skin thickness (epidermis and dermis) and VPT or TPT. Methods: Perception thresholds were measured on the volar side of the fingertip on 148 male subjects, out of which 116 were manual workers exposed to hand-transmitted vibration and 32 were white-collar (office) workers. Skin thickness was measured using a high-frequency ultrasonic derma scanner system. Results: The difference in age, perception thresholds and skin thickness between manual and office workers was small and non-significant except for the perception of cold, which was decreased by vibration exposure. Skin thickness for both subgroups was mean 0.57 mm (range 0.25–0.93 mm). Increased age was associated with decreased perception of warmth and vibration. Lifetime cumulative exposure to vibration, but not age, was associated with decreased perception of cold. Conclusion: No association (p > .05) was found between finger skin thickness in the range of about 0.1–1 mm and vibration perception threshold for test frequencies from 8 to 500 Hz and thermotactile perception thresholds for warmth and cold. Increasing age was associated with reduced perception of vibration and warmth. Vibration exposure was associated with decreased perception of cold. Significance: Skin thickness is a factor that may affect the response from sensory receptors, e.g., due to mechanical attenuation and thermal insulation. Thus, to evaluate perception threshold measurements, it is necessary to know if elevated thresholds can be attributed to skin thickness. No previous studies have measured skin thickness as related to vibrotactile and thermotactile perception thresholds. This study showed no association between skin thickness and vibrotactile perception or thermotactile perception. Keywords: Vibrotactile, Thermotactile, Skin thickness, Perception, Threshold, Vibration