Application of tRNS to improve Multiple Sclerosis Fatigue: a sham-controlled study

Background and aims: Fatigue is one of the most common, early, and disabling symptom in Multiple Sclerosis (MS). tDCS on Dorso-Lateral Prefrontal Cortex seems to give positive results on MS fatigue. Recently, a new stimulation protocol, transcranial Random Noise Stimulation (tRNS), showed powerful facilitatory effects on motor cortex in healthy subjects and ameliorated pain in MS patients. Here we aimed to explore effects of motor cortex tRNS in MS fatigue.Methods: 13 MS fatigued patients were enrolled in a blind, sham controlled tRNS study. 7 patients received 1.5 mA, 101-640 Hz tRNS stimulation and 6 patient received sham stimulation, both stimulations applied daily over M1 for 15 minutes, for two consecutive weeks. Outcome measures were Modified Fatigue Impact Scale (MFIS) for fatigue, BICAMS for cognitive impact, Purdue Pegboard for manual dexterity, Timed 25 Foot Walking Test (T25FWT) for fatigability, MSQoL-54 for quality of life.Results: ANOVA showed statistically significant improvement in MFIS physical subscale in real stimulation group (Real-p=0.004, Sham-p=0.22). SDMT scores improved only in tRNS subjects (p=0.01). MSQoL-54 scores showed a significative improvement only in tRNS patient (REAL-p=0.02, Sham-p=0.5) Patient Global Impression of Perceived Fatigue was significatively reduced in tRNS group (p=0,005). Conclusion: tRNS on primary motor cortex can decrease MS fatigue. If further studies on larger samples validated and strengthened the results obtained so far, the development of stimulation device suitable for self-managed home based treatment should be strongly pursued to optimize management of such disabling symptom in MS.