Transcutaneous electrical nerve stimulation (TENS) is commonly used in neurorehabilitation for the treatment of pain and spasticity. The long-term effects of sensory stimulation by means of TENS on hand sensitivity were investigated in patients with multiple sclerosis (MS). TENS was applied for 3 weeks (1 hour per day) on the median nerve region of the dominant hand. Sensitivity was assessed by the Semmes-Weinstein monofilaments before and 12 hours following the last intervention as well as 3 weeks later. Long-lasting increases in tactile sensitivity were achieved by repetitive stimulation of sensory afferents with TENS in MS patients but not in healthy subjects. This increased sensitivity was not only restricted to the median nerve area but also expanded to the ulnar nerve area. Remarkably, MS patients reached the same level of sensitivity as healthy subjects immediately after the intervention, and long-term effects were reported 3 weeks later.
The findings of this study demonstrated lasting improvements in tactile sensitivity of the fingers as a result of a long-term TENS intervention in MS patients, who ultimately reached a level comparable with that of healthy subjects.