Ardolino et al. conducted a study in which they recruited a sample of 11 patients diagnosed with HSP (eight affected by spastin/SPG4,1 by atlastin1/SPG3a, 1 by paraplegin/SPG7 and 1 by ZFYVE26/SPG15) with the purpose of investigating the effects of spinal direct current stimulation (tsDCS). This evidence concerns the gene SPAST and hereditary spastic paraplegia.