The effect of spasticity severity on peripheral muscle oxygenation in hemiparetic stroke patients: a cross-sectional study.

Background: Spasticity-induced muscle changes affect structure and metabolism. Little is known about the effect of stroke-related muscle changes on peripheral muscle oxygenation.

Objective: To investigate the effect of spasticity severity on peripheral muscle oxygenation in patients with hemiparetic stroke.

Methods: This cross-sectional study was conducted with 20 hemiparetic stroke patients and 10 healthy individuals. The hemiparetic stroke patients were divided into the high-level spasticity group (HLS, MAS ≥ 2) and the low-level spasticity group (LLS, MAS < 2). Healthy individuals were included in the control group (CG). Gastrocnemius muscle oxygenation was measured with near-infrared spectroscopy at rest, during activity (6-minute walk test and stair climbing test) and after activity. Ankle plantar flexor spasticity was evaluated with the Modified Ashworth Scale (MAS). Secondary outcome measures were motor recovery, disability level, and calf adipose tissue thickness.

Results: Resting average muscle oxygenation was lower in HLS than in CG ( = .021). Muscle oxygenation changes from baseline to final values were lower in HLS than in LLS after 6-minute walk test ( = .037) and lower than in CG after stair climbing test ( = .011). Baseline and final muscle oxygen saturation were lower in HLS, differences were not significant. In HLS, muscle oxygen saturation during 6-minute walk test increased unexpectedly, while it decreased during recovery.

Conclusions: Spasticity severity affected peripheral muscle oxygenation. In patients with high-level spasticity, resting average muscle oxygenation and changes in muscle oxygenation during recovery were lower, and different patterns were observed during 6MWT, suggesting impaired oxygen utilization and delivery, possibly related to spasticity severity.

Trial Registration: Clinical trial registry: NCT06362954.