Original article
Influence of Electric Somatosensory Stimulation on Paretic-Hand Function in Chronic Stroke

https://doi.org/10.1016/j.apmr.2005.11.019Get rights and content

Abstract

Wu CW, Seo H-J, Cohen LG. Influence of electric somatosensory stimulation on paretic-hand function in chronic stroke.

Objective

To test the influence of electric somatosensory stimulation on performance of the Jebsen-Taylor Hand Function Test (JTHFT), a widely used assessment of functional hand motor skills, by the paretic arm in patients with chronic stroke.

Design

Initially, patients trained for several sessions until reaching plateau performance on the JTHFT. Subsequently, they entered a crossover randomized study, designed to evaluate the influence of somatosensory stimulation on JTHFT performance.

Setting

A research laboratory.

Participants

Nine patients with chronic stroke (≥1.5y) who acutely had marked weakness (paralysis of the upper extremity is evaluated as equal or below Medical Research Council [MRC] grade 2) followed by improvement to an MRC grade of 4.24±0.43 (range, 3.5–4.9) and Fugl-Meyer Assessment (FMA) score of 86.43%±2.02% at the time of testing.

Interventions

Two hours of electric somatosensory stimulation was applied to the (1) paretic hand, (2) paretic leg, or (3) no stimulation in different sessions, in a randomized order.

Main Outcome Measure

The time required to complete the JTHFT was analyzed by using repeated-measures analysis of variance (ANOVA) with factors time (pre-, postintervention) and intervention (paretic hand, paretic leg, no stimulation) followed by post hoc testing.

Results

Significant effects of intervention and intervention by time interaction (P<.01) on JTHFT time was revealed by repeated-measures ANOVA. Post hoc testing documented improvements in JTHFT time with paretic hand stimulation alone (P<.005), an effect that appeared more prominent in subjects with lower FMA scores.

Conclusions

Somatosensory stimulation applied to a paretic limb can benefit performance of a functional test in patients with chronic stroke. This result supports the proposal that electric sensory stimulation in combination with training protocols may enhance the benefit of customary neurorehabilitative treatments and possibly motor learning.

Section snippets

Participants

Nine patients, an average of 64.5±4.4 years old (4 women; all right-hand dominant), with history of a single ischemic cerebral infarct (6 subcortical, 1 cortico-subcortical, 2 cortical) (table 1,fig 1) equal to or more than 1.5 years (6.5±1y; range, 1.5–13.3y) before testing participated in the study. All had initially severe motor paresis (below Medical Research Council [MRC] scale grade 2) as described in the patients’ chart and subsequently recovered to MRC grade 3.5 to 4.9 and Fugl-Meyer

Results

The familiarization period resulted in progressive performance improvements in the paretic hand expressed as reductions in JTHFT time (for raw and normalized data, P<.05; see figs 2B, 2C). JTHFT time at the end of the familiarization period was comparable to baseline JTHFT determinations (taken from the average of 3 repetitions before each intervention) in the 3 testing sessions.

Repeated-measures ANOVA showed significant effects of intervention and intervention by time interaction on JTHFT time

Discussion

The main result of this study was that a single 2-hour application of electric somatosensory stimulation of the paretic hand in patients with chronic stroke led to improvement in performance of a functional hand motor test relative to stimulation of the paretic leg and to no stimulation.

Hand motor deficits play an important role in stroke disability.29 Previous reports showed that application of electric somatosensory stimulation in patients with chronic stroke over weeks to months led to

Conclusions

Somatosensory stimulation applied to a paretic limb can benefit performance of a functional test in patients with chronic stroke, supporting the proposal that in combination with training protocols electric somatosensory stimulation may enhance the benefit of customary neurorehabilitative interventions and possibly motor learning.

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    Published as an abstract of the Fifth World Stroke Congress, June 2004, Vancouver, BC, Canada.

    No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.

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