Quantification of Tissue Oxygen Saturation in the Vastus Lateralis Muscle of Chronic Stroke Survivors During a Graded Exercise Test

Abstract

Purpose: 

This study examined tissue oxygen saturation (StO₂) of the vastus lateralis (VL) muscles of chronic stroke survivors during a graded exercise test (GXT). We hypothesized that the reduction in StO₂ will be blunted in the paretic versus nonparetic VL during a maximum effort GXT.

Methods: 

Chronic stroke survivors performed a GXT, and StO₂ of the VL in each leg was measured using near-infrared spectroscopy. Twenty-six stroke survivors performed a GXT.

Results: 

At rest, there was no difference in StO₂ between the paretic and nonparetic VL (65 ± 9% vs 68 ± 7%, respectively, P = .32). The maximum change in StO₂ from rest during the GXT was greater in the nonparetic versus the paretic VL (−16 ± 14% vs −9 ± 10%, respectively, P < .001). The magnitude of the oxygen resaturation response was also greater in the nonparetic versus the paretic VL (29 ± 23% vs 18 ± 15%, respectively, P < .001). VO₂ peak was associated with the magnitude of the VL StO₂ change during (r² = 0.54, P < .0001) and after (r² = 0.56, P < .001) the GXT.

Conclusion: 

During a GXT, there is a blunted oxygen desaturation response in the paretic versus the nonparetic VL of chronic stroke survivors. In the paretic VL, there was a positive correlation between the oxygen desaturation response during the GXT and VO₂ peak.