Spinal direct current stimulation (tsDCS) in hereditary spastic paraplegias (HSP): A sham-controlled crossover study

Abstract

<b>Objective</b>: Hereditary spastic paraplegia (HSP) represents a heterogeneous group of neurodegenerative diseases characterized by progressive spasticity and lower limb weakness. We assessed the effects of transcutaneous spinal direct current stimulation (tsDCS) in HSP.<b>Design:</b> A double-blind, randomized, crossover and sham-controlled study.<b>Setting</b>: Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico, Milan.<b>Participants</b>: eleven patients with HSP (six men, mean age ± SD: 37.3 ± 8.1 years), eight affected by spastin/SPG4,1 by atlastin1/SPG3a, 1 by paraplegin/SPG7 and 1 by ZFYVE26/SPG15.<b>Interventions</b>: tsDCS (anodal or sham, 2.0 mA, 20', five days) delivered over the thoracic spinal cord (T10-T12).<b>Outcome measures:</b> Motor-evoked potentials (MEPs), the H-reflex (Hr), F-waves, the Ashworth scale for clinical spasticity, the Five Minutes Walking test and the Spastic Paraplegia Rating Scale (SPRS) were assessed. Patients were evaluated before tsDCS (<i>T</i>₀), at the end of the stimulation (<i>T</i>₁), after one week (<i>T</i>₂), one month (<i>T</i>₃) and two months (<i>T</i>₄).<b>Results:</b> The score of the Ashworth scale improved in the anodal compared with sham group, up to two months following the end of stimulation (T₁, P = .0137; T₄, P = .0244), whereas the Five Minutes Walking test and SPRS did not differ between the two groups. Among neurophysiological measures, both anodal and sham tsDCS left Hr, F-waves and MEPs unchanged over time.<b>Conclusions:</b> Anodal tsDCS significantly decreases spasticity and might be a complementary strategy for the treatment of spasticity in HSP.