PURPOSE: The purpose of this study was to determine the association between electromyography-triggered neuromuscular electrical stimulation (ETMS) duration over an 8-wk intervention period with paretic upper-extremity (UE) impairment and functional limitation. Researchers hypothesized that Fugl-Meyer Assessment (FMA) and Arm Motor Ability Test (AMAT) scores would be positively and significantly with duration of use.

RATIONALE: Among stroke survivors, UE hemiparesis is a frequent residual impairment, affecting function and participation in meaningful occupations. Neuromuscular electrical stimulation (NMES), specifically ETMS, is a modality used in both clinical and research environments to increase poststroke UE active range of motion by utilizing visual biofeedback. Although some evidence suggests that longer NMES durations convey greater paretic UE motor changes in chronic stroke, the optimal duration of any NMES regimen in subacute stroke remains unknown.

DESIGN: This was a secondary analysis of data obtained from a multicenter randomized controlled trial.

PARTICIPANTS: Forty-one participants (>18 yr) in the subacute stroke phase exhibiting mild, stable UE hemiparesis and meeting specific UE motor criteria were included.

METHOD: The UE section of the FMA was used to assess UE impairment and the Functional Ability (FA) scale of AMAT was used to assess execution of common household activities. ETMS was applied to participants’ paretic UE wrist and finger extensors during two 40-min sessions per day, occurring 5 days/wk over an 8-wk period.

ANALYSIS: Participant demographics, duration of electrical stimulation, and outcome measures were evaluated using descriptive statistics. Variables were analyzed using Wilcoxon signed-rank test and Spearman’s rho correlation.

RESULTS: FMA and AMAT scores each increased significantly from baseline to end of intervention (mean [M] = 28.4, standard deviation [SD] = 16.1, at final testing on the FMA [Z = –4.58, p < .001]; M = 1.85 points, SD = 1.21, at baseline to M = 2.45 points, SD = 1.47, at final visit on the AMAT [Z = –4.41, p < .001]). However, no association was found between total ETMS use and changes on either scale at end of intervention (FMA, ρ = –.072; p = .65; AMAT, ρ = .079; p = .62). ETMS significantly reduces UE impairment and functional limitation, but the overall number of minutes for which it is administered appears less critical in the subacute phase.

DISCUSSION: This study identified significant participant benefits based on ETMS use, but no differences existed in response to ETMS duration. Data in this study strongly indicate that participants with more recent stroke (measured in days) exhibit larger FMA and AMAT score improvements, corresponding to a larger response to ETMS.

IMPACT STATEMENT: This study reveals that duration of ETMS is not directly related to motor outcomes in people with subacute stroke. Rather, the findings demonstrate that people who engage in early rehabilitation are more likely to experience improved motor outcomes.