The effect of transcranial direct current stimulation on chronic neuropathic pain in patients with multiple sclerosis: randomized controlled trial

Objective: Chronic neuropathic pain is a common symptom in multiple sclerosis (MS). This randomized controlled single-blinded study investigated whether a new protocol involving five days of transcranial direct current stimulation (tDCS) with an interval period would be effective to reduce pain using the visual analog scale (VAS). Other secondary outcomes included the Neuropathic Pain Scale (NPS), Depression Anxiety Stress Score (DASS), Short Form McGill Pain Questionnaire (SFMPQ), and Multiple Sclerosis Quality of Life 54 (MSQOL54). Design: A total of 30 participants were recruited for the study, with 15 participants randomized to a sham group or and 15 randomized to an active group. After a five-day course of a-tDCS, VAS and NPS scores were measured daily and then weekly after treatment up to four weeks after treatment. Secondary outcomes were measured pretreatment and then weekly up to four weeks. Results: After a five-day course of a-tDCS, VAS scores were significantly reduced compared with sham tDCS and remained significantly low up to week 2 post-treatment. There were no statistically significant mean changes in MSQOL54, SFMPQ, NPS, or DASS for the sham or treatment group before treatment or at four-week follow-up. Conclusions: This study shows that repeated stimulation with a-tDCS for five days can reduce pain intensity for a prolonged period in patients with MS who have chronic neuropathic pain.