Effect of vibration characteristics and vibror arrangement on the tactile perception of the upper arm in healthy subjects and upper limb amputees.
J NeuroEngineering Rehabil. 2019-11-13; 16(1):
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Guemann M(1), Bouvier S(2), Halgand C(3), Paclet F(3), Borrini L(4), Ricard D(5), Lapeyre E(4), Cattaert D(3), Rugy A(3)(6).
(1)Team HYBRID; INCIA laboratory, CNRS UMR 5287, University of Bordeaux, 146 rue Leo Saignat, Bordeaux, 33076, France. .
(2)University Descartes, Paris, France.
(3)Team HYBRID; INCIA laboratory, CNRS UMR 5287, University of Bordeaux, 146 rue Leo Saignat, Bordeaux, 33076, France.
(4)Departement of Rehabilitation at the Army instruction Hospital, 1 Rue du Lieutenant Raoul Batany, Clamart, 92190, France.
(5)Department of Neurology at the Army instruction Hospital, 1 Rue du Lieutenant Raoul Batany, Clamart, 92190, France.
(6)Centre for sensorimotor performance HMNS, University of Queensland, Brisbane, Australia.
Vibrotactile stimulation is a promising venue in the field of prosthetics to retrain sensory feedback deficits following amputation. Discrimination is well established at the forearm level but not at the upper arm level. Moreover, the effects of combining vibration characteristics such as duration and intensity has never been investigated.
METHOD: We conducted experiments on spatial discrimination (experiment 1) and tactile intensity perception (experiment 2), using 9 combinations of 3
intensities and 3 durations of vibror stimulations device. Those combinations were tested under 4 arrangements with an array of 6 vibrors. In both experiments,
linear orientation aligned with the upper arm longitudinal axis were compared to circular orientation on the upper arm circumference. For both orientations,
vibrors were placed either with 3cm space between the center of 2 vibrors or proportionally to the length or the circumference of the subject upper arm. Eleven heathy subjects underwent the 2 experiments and 7 amputees (humeral level) participated in the spatial discrimination task with the best arrangement found.
RESULTS: Experiment 1 revealed that circular arrangements elicited better scores than the linear ones. Arrangements with vibrors spaced proportionally elicited
better scores (up to 75% correct) than those with 3 cm spacing. Experiment 2, showed that the perceived intensity of the vibration increases with the intensity
of the vibrors’ activation, but also with their duration of activation. The 7 patients obtained high scores (up to 91.67% correct) with the circular
proportional (CP) arrangement.
DISCUSSION: These results highlight that discrete and short vibrations can be well discriminated by healthy subjects and people with an upper limb amputation.
These new characteristics of vibrations have great potential for future sensory substitution application in closed-loop prosthetic control.