Background: Sleep disorders are common in multiple sclerosis (MS) patients. These disturbances detrimentally impact both their physical and mental well-being, leading to increased difficulties in executing everyday tasks. To date, there is a lack of comprehensive research regarding the influence of transcranial direct current stimulation (TDCS) on sleep in MS patients.
Purpose: This randomized controlled trial was conducted to assess the TDCS effect on sleep subjectively and objectively in MS patients.
Setting: Outpatient Clinics of Center for Psychiatry, Neurology, and Neurosurgery, Tanta University.
Methods: Thirty-eight female MS patients with remission and relapse course aging from 25 to 40 years were randomly assigned into two equal groups (study and control group). The study group received  active TDCS plus selected physiotherapy program (diaphragmatic breathing exercise and  relaxation technique) and the control group received sham TDCS plus the same selected physiotherapy program. The assessment of daytime sleepiness was conducted through the Epworth Daytime Sleepiness Scale (ESS), while the Pittsburgh Sleep Quality Index (PSQI) was employed to evaluate quality of sleep. Sleep was assessed objectively using Polysomnography (PSD) device. The following parameters were assessed objectively (sleep latency, arousal index, sleep efficiency and total time sleep). Evaluation of all variables took place pretreatment and posttreatment.       
Results: There were no statistically significant differences between both groups in pretreatment mean values of all measured variables.  There were a statistically significant improvement in all measured variables in both groups after treatment. There were significant differences in all measured variables between both groups,  favoring the study group.
Conclusion: Transcranial direct current stimulation could be an excellent supplement to selected physiotherapy program in improving daytime sleepiness and quality of sleep in MS patients.