The effect of long-term TENS treatment on cortical neural plasticity and fine motor skills in multiple sclerosis

Abstract

Introduction Recently, Cuypers et al. (2010) showed that long-term TENS on the thenar eminence was able to induce long-term sensitivity changes in the fingers of the stimulated hand in MS-patients. In healthy adults, Meesen et al. (2010) reported significant increases in cortical motor representation in the stimulated and adjacent hand and arm muscles after long-term TENS. The mechanisms underlying these changes are not investigated in patients with MS. Therefore the aim of this study was to explore the effects of long-term TENS on cortical neural plasticity and fine motor skills. Methods Thirteen MS-patients were assigned to the TENS or SHAM group. Five patients participated in both groups. TENS was applied for 3 weeks, 1 hour a day. For SHAM the procedure was identical, however no current was applied. During the experiment sensitivity, fine motor skills and cortical motor representation was measured at baseline (PRE), after the intervention (POST) and 3 weeks after the end of the intervention (FOLLOW-UP). Results For the TENS group, ANOVA revealed significant changes in map AREA over time (p = .045). Moreover, a significant decrease in AREA was reported at POST (ES = 24.05%; p = .038). Additionally, changes in sensitivity over time were reported (p = .028). More specifically, a significant increase in sensitivity was reported at POST (p = .043). No significant changes were reported for map VOLUME or fine motor skills (p > .05). For the SHAM group no significant changes were reported in any of the measurements (p > .05). Between the TENS and SHAM group no significant differences were reported (p > .05).

Conclusion Long-term TENS leads to a decrease in cortical motor representation in MS-patients. Furthermore, improvements in tactile sensitivity were found immediately after TENS. Although changes in fine motor skills were expected after TENS, no significant results were found.