Randomized controlled trial of surface peroneal nerve stimulation for motor relearning in lower limb hemiparesis

Abstract

Objective: To compare the motor relearning effect of a surface peroneal nerve stimulator (PNS) versus usual care on lower limb motor impairment, activity limitation, and quality of life among chronic stroke survivors.

Design: Single-blinded randomized controlled trial.

Setting: Teaching hospital of academic medical center.

Participants: Chronic stroke survivors (N=110; >12wk poststroke) with unilateral hemiparesis and dorsiflexion strength of ≤4/5 on the Medical Research Council scale.

Interventions: Subjects were stratified by motor impairment level and then randomly assigned to ambulation training with either a surface PNS device or usual care (ankle-foot orthosis or no device) intervention. Subjects were treated for 12 weeks and followed up for 6 months posttreatment.

Main outcome measures: Lower limb portion of the Fugl-Meyer (FM) Assessment (motor impairment), the modified Emory Functional Ambulation Profile (mEFAP) performed without a device (functional ambulation), and the Stroke Specific Quality of Life (SSQOL) scale.

Results: There was no significant treatment group main effect or treatment group by time interaction effect on FM, mEFAP, or SSQOL raw scores (P>.05). The time effect was significant for the 3 raw scores (P<.05). However, when comparing average change scores from baseline (t1) to end of treatment (t2, 12wk), and at 12 weeks (t3) and 24 weeks (t4) after end of treatment, significant differences were noted only for the mEFAP and SSQOL scores. The change in the average scores for both mEFAP and SSQOL occurred between t1 and t2, followed by relative stability thereafter.

Conclusions: There was no evidence of a motor relearning effect on lower limb motor impairment in either the PNS or usual-care groups. However, both the PNS and usual-care groups demonstrated significant improvements in functional mobility and quality of life during the treatment period, which were maintained at 6-month follow-up.

Trial registration: ClinicalTrials.gov NCT00148343.

Figure 1

Participant Flow Diagram. AFO: ankle foot orthosis.

Figure 2

Plot of adjusted means over time (weeks) for Fugl-Meyer (FM) scores including standard error bars. PNS: peroneal nerve stimulation; UC: usual care.

Figure 3

Plot of adjusted means over time (weeks) for the Modified Emory Functional Ambulation (mEFAP) scores (secs) including standard error bars. PNS: peroneal nerve stimulation; UC: usual care.

Figure 4

Plot of adjusted means over time (weeks) for the Stroke Specific Quality of Life (SSQOL) scores including standard error bars. PNS: peroneal nerve stimulation; UC: usual care.