Distal Versus Proximal Arm Improvement Following Paired Vagus Nerve Stimulation Therapy After Chronic Stroke

Arch Phys Med Rehabil. 2024 May 28:S0003-9993(24)01014-1. doi: 10.1016/j.apmr.2024.05.018. Online ahead of print.


OBJECTIVE: To evaluate differences in upper extremity (UE) segment-specific (proximal or distal segment) recovery after Vagus nerve stimulation (VNS) paired with UE rehabilitation (Paired-VNS) compared to rehabilitation with sham-VNS (Control). We also assessed whether gains in specific UE segments predicted clinically meaningful improvement.

DESIGN: This study reports on a secondary analysis of the randomized, triple-blinded, sham-controlled pivotal VNS-REHAB trial. A Rasch latent regression was used to determine differences between Paired-VNS and Controls for distal and proximal UE changes after in-clinic therapy and 3-months later. Subsequently, we ran a random forest model to assess candidate predictors of meaningful improvement. Each item of the Fugl-Meyer Assessment-Upper Extremity and Wolf Motor Function Test was evaluated as a predictor of response to treatment.

SETTING: Data analyzed in this study were obtained from the completed VNS-REHAB trial. Participants received intensive UE rehabilitation from physical and occupational therapists in an outpatient setting for 6 weeks, followed by a home-based exercise program.

PARTICIPANTS: Dataset included 108 participants with chronic ischemic stroke and moderate-to-severe UE impairments.

INTERVENTIONS: N/A MAIN OUTCOME MEASURES: Fugl-Meyer Assessment-Upper Extremity (FMA-UE) and Wolf Motor Function Test (WMFT) RESULTS: Distal UE improvement was significantly greater in the Paired-VNS group compared to Controls immediately post-therapy (95% CI [0.27-0.73], p≤0.001) and after 3-months (95% CI [0.16-0.75], p=0.003). Both groups showed similar improvement in proximal UE at both time points. A subset of both distal and proximal items from the FMA-UE and WMFT were predictors of meaningful improvement.

CONCLUSIONS: Paired-VNS improved distal UE impairment in chronic stroke to a greater degree than intensive rehabilitation alone. Proximal improvements were equally responsive to either treatment. Given that meaningful UE recovery is predicted by improvements across both proximal and distal segments, Paired-VNS may facilitate improvement that is otherwise elusive.

PMID:38815953 | DOI:10.1016/j.apmr.2024.05.018