Sensory supplementation system based on electrotactile tongue biofeedback of head position for balance control

Abstract

The present study aimed at investigating the effects of an artificial head position-based tongue-placed electrotactile biofeedback on postural control during quiet standing under different somatosensory conditions from the support surface. Eight young healthy adults were asked to stand as immobile as possible with their eyes closed on two Firm and Foam support surface conditions executed in two conditions of No-biofeedback and Biofeedback. In the Foam condition, a 6-cm thick foam support surface was placed under the subjects' feet to alter the quality and/or quantity of somatosensory information at the plantar sole and the ankle. The underlying principle of the biofeedback consisted of providing supplementary information about the head orientation with respect to gravitational vertical through electrical stimulation of the tongue. Centre of foot pressure (CoP) displacements were recorded using a force platform. Larger CoP displacements were observed in the Foam than Firm conditions in the two conditions of No-biofeedback and Biofeedback. Interestingly, this destabilizing effect was less accentuated in the Biofeedback than No-biofeedback condition. In accordance with the sensory re-weighting hypothesis for balance control, the present findings evidence that the availability of the central nervous system to integrate an artificial head orientation information delivered through electrical stimulation of the tongue to limit the postural perturbation induced by alteration of somatosensory input from the support surface.

Vestibular rehabilitation with biofeedback in patients with central imbalance

“…This device is able to inform the CNS about head position -information which usually comes from the vestibular system, through tongue electrotactile stimulation 8 . In order for the brain to properly interpret the information from the sensorial substitution equipment, it is not necessary that it is presented the same way as the natural sensorial system.…”

Effectiveness of an electro-tactile vestibular substitution system in improving upright postural control in unilateral vestibular-defective patients

“…Recently, a head positionbased tongue placed biofeedback system has been developed to supply the user with additional information about his/her head orientation/motion, normally provided by the vestibular system (e.g. [1,2]) through electro-tactile stimulation of his/ her tongue [3][4][5][6]. Whereas previous studies have evidenced the effectiveness of this biofeedback system in improving upright postural control as a sensory supplementation for an alteration of somatosensory information from the ankles and foot soles [5,6], whether this biofeedback system could help individuals to improve their upright postural control, as a sensory substitution for loss of vestibular information, remained to be investigated.…”

Effectiveness of a tongue-placed electrotactile biofeedback to improve ankle force sense following plantar-flexor muscles fatigue

“…The Fatigue condition was executed 5 min after the No fatigue condition. recently observed in sensory conditions of absent visual information [15], altered foot and ankle somatosensory information [6,16], and degraded vestibular and neck proprioceptive information [17,18]. Finally, even though the present study has been conducted in young healthy individuals, we believe that the present findings could have significant implications in the fields of orthopaedics and rehabilitation, for increasing/restoring the ability to sense force at the ankle.…”

“…Among the available biofeedback systems, those designed to employ electrotactile stimulation of the tongue to provide augmented information have received growing interest (e.g. [3][4][5][6]). These biofeedback systems present indeed the advantage of freeing visual and auditory channels by using another unexploited sensory channel to convey information, that could provide a perspective for their application outside the laboratory framework and permit their use over long-time period in real-life environment [3].…”