Vibrotactile mapping of the upper extremity: Absolute perceived intensity is location-dependent; perception of relative changes is not

Abstract

Vibrotactile sensation is an essential part of the sense of touch. In this study, the localized vibrotactile sensation of the arm-shoulder region was quantified in 10 able-bodied subjects. For this analysis, the six relevant dermatomes (C3-T2) and three segments—the lower arm, the upper arm, and the shoulder region were studied. For psychometric evaluation, tasks resulting in the quantification of sensation threshold, just noticeable difference, Weber fraction, and perception of dynamically changing vibrotactile stimuli were performed. We found that healthy subjects could reliably detect vibration in all tested regions at low amplitude (2–6% of the maximal amplitude of commonly used vibrotactors). The detection threshold was significantly lower in the lower arm than that in the shoulder, as well as ventral in comparison with the dorsal. There were no significant differences in Weber fraction (20%) detectable between the studied locations. A compensatory tracking task resulted in a significantly higher average rectified error in the shoulder than that in the upper arm, while delay and correlation coefficient showed no difference between the regions. Here, we presented a conclusive map of the vibrotactile sense of the healthy upper limb. These data give an overview of the sensory bandwidth that can be achieved with vibrotactile stimulation at the arm and may help in the design of vibrotactile feedback interfaces (displays) for the hand/arm/shoulder-region.

Vibrotactile Feedback for a Person with Transradial Amputation and Visual Loss: A Case Report

“…Phantom limb maps are a phenomenon experienced by some persons with amputation, where they report sensations, such as a touch of the amputated limb, on specific areas of the residual limb [33][34][35][36]. Surgical procedures such as targeted muscle reinnervation (TMR) [37] and rerouting sensory afferent fibers to skin areas during targeted sensory reinnervation (TSR) [17,38] can promote the development of peripheral phantom limb maps, helping to enable bidirectional neural interfaces to both receive information from and transmit information to prostheses [39]. FEELIX is a prosthesis add-on and non-invasive closed-loop somatosensory feedback prototype developed to improve manual dexterity in persons with transradial amputation.…”