The goal of this clinical trial is to learn if brain stimulation can improve movement and daily function in people with multiple sclerosis (MS). The study will also look at how this treatment affects fatigue, sleep, memory and attention, and quality of life. The main questions this study aims to answer are the following: Does this treatment improve coordination and balance? Does it reduce fatigue and improve sleep and daily life? Does it change brain activity? Researchers will compare active brain stimulation to sham stimulation (a look-alike treatment that does not deliver real stimulation) to see if the treatment works. Participants will: Receive brain stimulation sessions for two weeks Attend assessment sessions before and after treatment Return for a follow-up visit after four weeks Complete tests of movement, fatigue, sleep, and thinking
Multiple sclerosis (MS) is a chronic immune-mediated neurological disorder characterized by demyelination and neurodegeneration within the central nervous system. Disruption of cerebro-cerebellar networks is a key feature of MS and contributes to impairments in motor coordination, balance, gait, fatigue, and cognitive performance. Cerebellar involvement is particularly associated with ataxia and postural instability, which significantly affect functional independence and quality of life. Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique capable of modulating cortical and cerebellar excitability. Previous studies investigating cerebellar tDCS in MS have reported variable findings, which may be related to heterogeneity in stimulation protocols, the predominant use of unilateral stimulation approaches, and the frequent combination of stimulation with task-oriented rehabilitation. These factors limit the ability to isolate the independent effects of neuromodulation. The cerebellum operates through bilateral cerebro-cerebellar loops, suggesting that bilateral stimulation may provide more comprehensive modulation of these distributed networks compared to unilateral approaches. In addition, the effects of tDCS are influenced by state-dependent factors, including concurrent motor activity. Delivering stimulation as a standalone intervention allows for clearer evaluation of its direct neuromodulatory effects without the confounding influence of concurrent rehabilitation. This study is designed as a randomized, double-blind, sham-controlled trial to evaluate the effects of bilateral cerebellar tDCS on multidomain dysfunction in individuals with MS. Participants will be randomly assigned to receive either active or sham stimulation. The intervention consists of repeated sessions of bilateral cerebellar stimulation delivered over a two-week period using a standardized protocol. The study aims to evaluate the effects of this intervention on motor and non-motor domains and to explore associated neurophysiological changes. By isolating the effects of bilateral cerebellar stimulation, this trial seeks to provide a clearer understanding of its therapeutic potential and to inform the development of targeted neuromodulation strategies in MS rehabilitation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
40
Bilateral cerebellar transcranial direct current stimulation (ctDCS) will be delivered using a constant-current stimulator. Anodal electrodes (5 × 5 cm; 25 cm²) will be positioned bilaterally over the cerebellar hemispheres (approximately 3 cm lateral to the inion), with reference electrodes placed over the buccinator muscles. Stimulation will be applied at 2 mA for 20 minutes per session. Participants will receive five sessions per week for two consecutive weeks (total of 10 sessions).
Sham bilateral cerebellar transcranial direct current stimulation (ctDCS) will be delivered using the same electrode placement as the active condition. The current will be ramped up and down at the beginning and end of the session to mimic the sensation of stimulation without delivering continuous current. Each session will last 20 minutes, with five sessions per week for two consecutive weeks (total of 10 sessions).
University of Sharjah
Sharjah city, United Arab Emirates
Scale for the Assessment and Rating of Ataxia (SARA)
The Scale for the Assessment and Rating of Ataxia (SARA) is an 8-item clinical scale used to assess cerebellar ataxia, including gait, stance, sitting balance, speech, and limb coordination. Total scores range from 0 (no ataxia) to 40 (most severe ataxia), where higher scores indicate worse ataxia.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after completion of the 10-session intervention), and at 4-week follow-up.
The balance evaluation systems test (mini-BESTest)
The Mini-Balance Evaluation Systems Test (Mini-BESTest) is a 14-item clinical scale assessing dynamic balance, including anticipatory control, reactive responses, sensory orientation, and gait stability. Total scores range from 0 (severe balance impairment) to 28 (normal balance), where higher scores indicate better balance performance.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Timed Up and Go (TUG)
The Timed Up and Go (TUG) test measures functional mobility as the time required to stand up from a chair, walk 3 meters, turn, return, and sit down. Measured in seconds (s), with no fixed minimum or maximum values, where lower times indicate better functional mobility.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Six-Minute Walk Test (6MWT)
The Six-Minute Walk Test (6MWT) assesses walking endurance by measuring the total distance walked over 6 minutes. Measured in meters (m), with no fixed maximum value, where higher distances indicate better functional performance.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Modified Tardieu Scale (MTS)
The Modified Tardieu Scale (MTS) assesses spasticity by measuring muscle response to passive stretch at different velocities, including angle of muscle reaction and quality of response. Scoring depends on joint and muscle group assessed and does not have a single fixed total score range; however, higher scores indicate greater spasticity (worse outcome).
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Modified Fatigue Impact Scale (MFIS)
The Modified Fatigue Impact Scale (MFIS) is a 21-item questionnaire assessing the impact of fatigue on physical, cognitive, and psychosocial function. Total scores range from 0 (no fatigue impact) to 84 (maximum fatigue impact), where higher scores indicate worse fatigue.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Pittsburgh Sleep Quality Index (PSQI)
The Pittsburgh Sleep Quality Index (PSQI) assesses sleep quality and disturbances over the past month. Total scores range from 0 (good sleep quality) to 21 (poor sleep quality), where higher scores indicate worse sleep quality.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Multiple Sclerosis Quality of Life-54 (MSQOL-54)
The Multiple Sclerosis Quality of Life-54 (MSQOL-54) is a multidimensional questionnaire assessing health-related quality of life, including physical and mental health domains. Composite scores range from 0 (poor quality of life) to 100 (best quality of life), where higher scores indicate better quality of life.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Symbol Digit Modalities Test (SDMT)
The Symbol Digit Modalities Test (SDMT) assesses cognitive processing speed by measuring the number of correct symbol-digit pairings completed within a fixed time period. Scores are reported as the number of correct responses, with no fixed maximum value, where higher scores indicate better cognitive performance.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Montreal Cognitive Assessment (MoCA)
The Montreal Cognitive Assessment (MoCA) is a screening tool for global cognitive function, including attention, memory, executive function, and visuospatial ability. Total scores range from 0 (severe impairment) to 30 (normal cognition), where higher scores indicate better cognitive function.
Time frame: Baseline (within 7 days prior to the first intervention session), immediately post-intervention (within 7 days after the final session), and 4 weeks post-intervention.
Resting-State EEG
Resting-state electroencephalography (EEG) will be used to assess cortical activity and neural oscillatory dynamics. Quantitative EEG analysis will be performed using power spectral density (PSD) to evaluate frequency-specific activity across standard frequency bands, including delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz).Measured in microvolts squared (µV²), with no fixed minimum or maximum values, where changes Absolute and relative power within each frequency band will be calculated. In addition, regional analysis (frontal, central, parietal regions) may be conducted to examine spatial distribution of cortical activity. Changes in EEG power spectral density are interpreted as indicators of altered cortical excitability and functional brain activity. For example, increases in alpha power may reflect improved neural efficiency and network organization, whereas changes in theta or beta activity may indicate modulation of cognitive and sensorimotor processes.
Time frame: Baseline (within 7 days prior to the first intervention session) and immediately post-intervention (within 7 days after the final session).
Motor Evoked Potential (MEP) Amplitude
Motor evoked potential (MEP) amplitude, measured using transcranial magnetic stimulation (TMS) over the primary motor cortex (M1), reflects corticospinal excitability. Values are expressed in millivolts (mV), with no fixed minimum or maximum values, where higher values indicate greater corticospinal excitability.
Time frame: Baseline (within 7 days prior to the first intervention session) and immediately post-intervention (within 7 days after the final session).
Resting Motor Threshold (RMT)
Resting motor threshold (RMT), measured using transcranial magnetic stimulation (TMS) over the primary motor cortex (M1), represents the minimum stimulation intensity required to elicit a motor response at rest. Values are expressed as a percentage of maximum stimulator output (%), with no fixed minimum or maximum values, where lower values indicate greater corticospinal excitability.
Time frame: Baseline (within 7 days prior to the first intervention session) and immediately post-intervention (within 7 days after the final session).
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