RESUMEN
PURPOSE: Post-polio syndrome develops about 20-40 years after acute paralytic poliomyelitis, and manifests with progressively deteriorating muscle strength and endurance. Here, we assessed whether transcranial direct current stimulation (tDCS) improves sleep and fatigue symptoms in patients with post-polio syndrome. METHODS: We enrolled 32 patients with a diagnosis of post-polio syndrome. tDCS (1.5 mA, 15 min) was delivered by a direct current stimulator connected to three electrodes: two anodal electrodes on the scalp over the right and left pre-motor cortex and the other above the left shoulder (cathode). 16 patients received anodal tDCS and the remainder sham tDCS. We evaluated changes induced by tDCS (daily for five days a week, for three weeks) on clinical scales (Short Form Health Survey [SF-36], Piper Fatigue Scale [PFS], Fatigue Severity Scale [FSS], 101-Point Numerical Rating [PNR-101], Hamilton Rating Scale for Depression [HRSD], Pittsburgh Sleep Quality Index [PSQI]) at baseline (T0) and three weeks later (T1). RESULTS: At T1 SF-36 sub-items physical functioning, role physical, vitality, social functioning and role emotional improved significantly more in patients who received tDCS (p < 0.01) than in sham-treated patients. Also, PSQI scores improved more in treated patients (p < 0.05, two-way ANOVA with "stimulation" and "time" as factors: p < 0.01). tDCS-induced benefits were more pronounced in patients who were younger at primary infection (p < 0.05). CONCLUSION: Anodal tDCS over the pre-motor areas for fifteen days improved sleep and fatigue symptoms in patients with post-polio syndrome. tDCS could be a non-invasive and valuable new tool for managing post-polio patients.