Can a Plantar Pressure-Based Tongue-Placed Electrotactile Biofeedback Improve Postural Control Under Altered Vestibular and Neck Proprioceptive Conditions?

TL;DR

This study demonstrates that plantar pressure-based tongue-placed electrotactile biofeedback can help maintain postural stability when vestibular and neck proprioceptive inputs are disrupted, especially during challenging head postures.

Contribution

It introduces a novel biofeedback system that improves postural control under altered sensory conditions by providing supplementary plantar pressure information via tongue stimulation.

Findings

Biofeedback reduced CoP displacements in extended head posture.

Subjects maintained stability with biofeedback despite sensory disruptions.

Results support sensory re-weighting in postural control.

Abstract

We investigated the effects of a plantar pressure-based tongue-placed electrotactile biofeedback on postural control during quiet standing under normal and altered vestibular and neck proprioceptive conditions. To achieve this goal, fourteen young healthy adults were asked to stand upright as immobile as possible with their eyes closed in two Neutral and Extended head postures and two conditions of No-biofeedback and Biofeedback. The underlying principle of the biofeedback consisted of providing supplementary information related to foot sole pressure distribution through a wireless embedded tongue-placed tactile output device. Centre of foot pressure (CoP) displacements were recorded using a plantar pressure data acquisition system. Results showed that (1) the Extended head posture yielded increased CoP displacements relative to the Neutral head posture in the No-biofeedback condition, with a greater effect along the anteroposterior than mediolateral axis, whereas (2) no significant difference between the two Neutral and Extended head postures was observed in the Biofeedback condition. The present findings suggested that the availability of the plantar pressure-based tongue-placed electrotactile biofeedback allowed the subjects to suppress the destabilizing effect induced by the disruption of vestibular and neck proprioceptive inputs associated with the head extended posture. These results are discussed according to the sensory re-weighting hypothesis, whereby the central nervous system would dynamically and selectively adjust the relative contributions of sensory inputs (i.e., the sensory weights) to maintain upright stance depending on the sensory contexts and the neuromuscular constraints acting on the subject.