Perceived ankle instability and cutaneous reflex modulation during gait

Area of Science:

• Neuromuscular control
• Motor learning
• Biomechanics

Background:

• Cutaneous reflexes aid gait stability by minimizing stumbles from perturbations.
• Individuals with chronic ankle instability (CAI) exhibit altered reflex patterns compared to healthy individuals.
• These alterations are hypothesized to stem from perceived instability in CAI.

Purpose of the Study:

• To investigate if cutaneous reflex variability and magnitude predict perceived instability during gait in individuals with CAI.
• To explore the relationship between sural nerve stimulation-evoked reflexes and subjective instability ratings.

Main Methods:

• Forty participants with CAI walked while receiving random sural nerve stimulations.
• Surface electromyography recorded lower leg muscle activity to calculate middle latency reflexes.
• Hierarchical logistical regressions analyzed the relationship between reflex characteristics and perceived instability.

Main Results:

• A positive association was found between reflex variability in the peroneus longus and lateral gastrocnemius muscles and perceived instability during midstance.
• Consistent reflexes were linked to lower perceived instability, possibly due to developed perceptual expectations.
• Variable motor outputs correlated with higher perceived instability at the supraspinal level.

Conclusions:

• Cutaneous reflex variability during gait may serve as an objective measure for neuromuscular recovery in CAI rehabilitation.
• Reflex variability could be a predictive indicator of future lateral ankle sprains.
• Understanding reflex modulation offers insights into motor control deficits in CAI.