Priming and task-specific training for arm weakness post stroke: A randomized controlled trial

Abstract

Objective: The objective of this work was to evaluate if task-specific training (TST) preceded by bilateral upper limb motor priming (BUMP) reduces upper limb impairment more than TST preceded by control priming ([CP], sham electrical stimulation) in people with chronic stroke.

Methods: In this single-blind, randomized controlled trial, 76 adults with moderate to severe upper limb hemiparesis ≥6 months post-stroke were stratified by baseline impairment and randomized to receive either BUMP or CP prior to receiving the same TST protocol. Participants completed 30 h of treatment in 15 days over 6 weeks. The primary outcome was change in Fugl-Meyer upper extremity (FMUE) from baseline to 8-week follow-up. We also report clinically meaningful response rates defined as a change in FMUE score of 6 points or greater.

Results: In response to treatment, both groups improved to a significant extent at follow-up, exceeding the FMUE minimum clinically important difference. Those in BUMP and CP saw a mean change of 5.68 (SE 0.76, p < 0.001) and 5.87 (SE 0.76, p < 0.001) respectively. There was no significant difference between treatment arms (mean difference of -0.20 (95% CI = [-2.37, 1.97], SE = 1.08, p = 0.86)). A response of ≥6 points was observed in 46% in BUMP and 50% in CP.

Interpretation: There was no beneficial effect of BUMP. The magnitude of change seen in both groups reflects the largest improvement achieved with just 22.5 h of TST in this population, matching or out-performing more invasive, time-intensive, and costly interventions proposed in recent years.

Figure 1

Participant timeline for each treatment visit.

Figure 2

Exsurgo priming device. Both wrists move in rhythmic, symmetrical, flexion, and extension at a target frequency of 1 Hz. Repetitions are tracked by a digital counter built into the device.

Figure 3

Trial profile. Dotted lines represent groups which did not complete study protocol but were included in the intention‐to‐treat analysis.

Figure 4

Change and response rates for the FMUE. (A) Comparison of mean FMUE scores at each timepoint for the BUMP (n = 37) and CP (n = 36) groups. The circle is the mean group value, and the vertical bars represent the standard error. (B) Individual FMUE scores at baseline and post‐test. (C) FMUE response rates (≥6‐point change from baseline to follow‐up, 8 weeks after treatment ended). BUMP, bilateral upper limb motor priming; CP, control priming; FMUE, Fugl‐Meyer Assessment of the upper extremity; PT, post‐test; FU, follow‐up.