Examination of Proprioceptive Reliance During Backward Walking in Individuals With Multiple Sclerosis

Slowed somatosensory conduction in multiple sclerosis (MS) increases postural instability and decreases proprioception. Despite these delays, individuals with MS rely more on proprioception for balance compared to controls. This heightened reliance, combined with slowed signal transduction, increases fall risk. Backward walking (BW) increases proprioceptive reliance by reducing visual cues. However, no study has conclusively linked proprioception to BW. This study aims to assess proprioception's role in BW compared to forward walking (FW) in MS and to compare differences in proprioception between MS fallers and non-fallers.

Fifty participants (average age: 50.34 ± 11.84, median Patient Determined Disease Steps [PDDS]: 2) completed the study. Participants completed BW and FW at comfortable and fast speeds. We have previously established vibration sensation as a proxy measure for proprioception. Vibration thresholds were quantified at the great toe bilaterally using a 2-alternative forced-choice procedure.

Significant correlations were seen for vibration sensation and FW comfortable ( ρ  = 0.35), FW fast ( ρ  = 0.34), BW comfortable ( ρ  = 0.46), and BW fast ( ρ  = 0.46). After controlling for age, sex, and PDDS, vibration sensation significantly predicted performance during all walking tasks, with larger beta coefficients seen during BW (comfortable β  = 0.57; fast β  = 0.58) compared to FW (comfortable β  = 0.41; fast β  = 0.45). Fallers performed significantly worse than non-fallers for vibration sensation ( P = 0.04).

Considering the notable decrease in proprioception in participants with MS and the clear distinction between fallers and non-fallers, it is crucial to conduct fall risk assessments and interventions focusing on proprioception. With its heightened reliance on proprioception, BW offers a promising method for assessing fall risk and could be an effective exercise intervention.

Video Abstract available for more insights from the authors (see the Supplemental Digital Content available at: http://links.lww.com/JNPT/A490 ).