Unlocking vestibular stimulation as a rehabilitation approach: an application of sensory reweighting

Sensory signals from the visual, vestibular, and proprioceptive systems are integrated based on their reliability to stabilize the trunk’s upright posture, in a process known as ‘sensory reweighting’ [1]. Individuals with low back pain rely less on lumbar proprioceptive signals for postural control during standing [2]. This study aimed to test whether prolonged stochastic electrical vestibular stimulation (EVS) could decrease the weighting of vestibular signals and increase the weighting of lumbar proprioception for trunk stabilization during walking in healthy individuals.

Eleven healthy young participants walked on a treadmill at 2.8 km/h for 70 minutes with eyes open. Stochastic EVS (2 to 25 Hz) was applied continuously for 50 minutes. Muscle vibration (80 Hz) was applied on the left paraspinal muscle at the L2 level, in series of fifteen 1-second vibrations with 2-second intervals. Vibration series were applied at 0, 30 and 50 minutes during EVS, and 10 minutes before and after EVS.

The weighting of lumbar proprioception was assessed by the muscle vibration induced mediolateral displacement of a cluster marker at the sixth thoracic level. Vestibular contribution was evaluated by the coherence and gain between the EVS signal and mediolateral ground reaction force (GRF). Generalized linear models were fitted to identify changes in sensory weighting over time.

EVS-GRF coherence and gain significantly decreased over time, while the response magnitude to muscle vibration increased. These findings suggests that prolonged EVS can downweigh the vestibular signal while upweighting lumbar proprioception. This may unlock EVS as a novel rehabilitation approach for proprioception impairments.