Proportional sway-based electrotactile feedback improves lateral standing balance.

Area of Science:

• Neuroscience
• Biomechanics
• Rehabilitation Engineering

Background:

• Plantar cutaneous augmentation enhances sensory feedback for balance rehabilitation.
• Previous studies focused on passive forms or lower-limb amputees.
• Active forms, like electrical stimulation, remain less explored in individuals with intact limbs.

Purpose of the Study:

• To investigate the effect of active plantar cutaneous augmentation via electrical stimulation on standing balance in healthy individuals.
• To compare the efficacy of discrete-mode versus proportional-mode electrotactile feedback.

Main Methods:

• Ten healthy subjects performed a balance task on a board while cognitive load was induced using an n-back task.
• Electrotactile feedback was applied to the heel in discrete or proportional modes, synchronized with lateral board sway.
• Balance time and sway duration were measured under different stimulation conditions.

Main Results:

• Proportional-mode electrotactile stimulation significantly increased balance time (1.86s to 1.98s, p=0.010) and sway duration (p=0.035).
• Discrete-mode electrotactile stimulation did not significantly improve balance time (p=0.669) or sway duration (p=0.053).
• The n-back task was used to minimize cognitive involvement in the balancing task.

Conclusions:

• Proportional-mode electrotactile stimulation is more effective than discrete-mode for improving standing balance.
• The effectiveness of proportional feedback may stem from its closer resemblance to natural foot pressure sensation.
• Active plantar cutaneous augmentation shows promise for balance rehabilitation in individuals with intact limbs.