Closing an open-loop control system: vestibular substitution through the tongue

Area of Science:

• Neuroscience
• Biomechanics
• Sensory Substitution

Background:

• Human postural coordination relies on multisensory integration within a complex closed-loop control system.
• Loss of vestibular input, crucial for balance, leads to postural instability, potentially due to open-loop control system noise.
• The brain can adapt by using tactile information from sensory substitution systems to compensate for sensory deficits.

Purpose of the Study:

• To investigate the restoration of head-body postural coordination through vestibular substitution.
• To evaluate the efficacy of a brain-machine interface employing electrotactile stimulation for vestibular compensation.
• To assess the persistence of postural stability after the removal of the vestibular substitution system.

Main Methods:

• Utilized a head-mounted accelerometer to capture head and body movement data.
• Employed a brain-machine interface delivering electrotactile stimulation patterns to the tongue for sensory substitution.
• Assessed postural stability during and after the application of the vestibular substitution system.

Main Results:

• Demonstrated successful restoration of head-body postural coordination using the described vestibular substitution method.
• Observed that postural stability was maintained for a period even after the vestibular substitution was removed.
• Confirmed that open-loop instability reappeared once the sensory substitution was discontinued.

Conclusions:

• Vestibular substitution via electrotactile stimulation can effectively restore postural coordination in individuals with vestibular loss.
• The brain exhibits plasticity, enabling functional compensation through sensory substitution.
• The findings highlight the potential of brain-machine interfaces for treating balance disorders.