This is a double-blind, parallel, randomized, sham-controlled pilot study evaluating the safety, feasibility, and efficacy of Gamma Sensory Stimulation (GSS) delivered via a Virtual Reality (VR) headset in individuals with Multiple Sclerosis (MS) who experience moderate to severe fatigue. Participants will be randomized (1:1) to 4 weeks of active GSS or sham stimulation, followed by a 4-week post-treatment follow-up. The primary objective is to determine whether GSS reduces fatigue, measured by the Modified Fatigue Impact Scale (MFIS). Secondary outcomes include additional fatigue scales, cognitive performance, quality-of-life measures, tolerability and safety.
Gamma Sensory Stimulation (GSS) is a non-invasive audiovisual neuromodulation method that delivers synchronized 40 Hz stimulation to engage gamma-band neural oscillations. Gamma-frequency activity is implicated in cognitive processing and large-scale network coordination, which may be disrupted in people with Multiple Sclerosis (MS), particularly in those experiencing fatigue. Prior research suggests that gamma-frequency entrainment may modulate neural network activity and support functional outcomes. This single-center, double-blind, randomized, sham-controlled pilot study investigates whether 4 weeks of GSS delivered through an immersive Virtual Reality (VR) system can reduce fatigue in individuals with MS. Participants with moderate to severe fatigue will be randomized in a 1:1 ratio to receive either active GSS or sham stimulation embedded in matched VR content. The intervention consists of 16 in-lab stimulation sessions delivered over 4 weeks (4 sessions per week). Each session includes 30 minutes of active stimulation within a standardized VR experience. The primary endpoint is the change in Modified Fatigue Impact Scale (MFIS) total score from baseline to End of Treatment (Week 4). Secondary endpoints include changes from baseline to End of Treatment (Week 4) and follow-up (Week 8) in additional validated fatigue measures (Fatigue Severity Scale, Visual Analogue Scale for Mental Fatigue, PROMIS Fatigue), cognitive performance assessed by the Symbol Digit Modalities Test (SDMT), quality-of-life measures (Neuro-QoL Fatigue), and the rate of change in Daily Fatigue Severity (DFS) across the treatment period. Exploratory outcomes include MFIS subscale scores, variability in daily fatigue ratings, embedded cognitive task performance during stimulation, and treatment acceptability. Safety and tolerability will be assessed through monitoring of adverse events, session attendance, and retention. Electroencephalography (EEG) will be collected at baseline and at End of Treatment (Week 4) for exploratory characterization of neural responses to gamma-frequency stimulation. This pilot investigation aims to generate preliminary safety, feasibility, and efficacy data to inform future multisite studies evaluating VR-based GSS as a potential at-home therapeutic approach for MS-related fatigue.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
30
Participants receive 30 minutes of Gamma Sensory Stimulation delivered through a virtual reality (VR) headset and headphones. Visual and auditory stimulation parameters are configured to deliver rhythmic sensory stimulation intended to engage gamma-band neural activity. Sessions occur four times per week for four weeks and are embedded within standardized VR environments.
Participants receive 30 minutes of sham sensory stimulation delivered through a virtual reality (VR) headset and headphones. The sham intervention uses identical VR environments, session duration, and procedures as the active intervention, providing an equivalent participant experience without delivering therapeutic stimulation. Sessions occur four times per week for four weeks.
Hospital del Mar
Barcelona, Barcelona, Spain
Change in Modified Fatigue Impact Scale (MFIS) total score
The Modified Fatigue Impact Scale (MFIS) is a 21-item patient-reported outcome assessing the impact of fatigue on physical, cognitive, and psychosocial functioning. Scores range from 0 to 84, with higher scores indicating greater fatigue impact. This outcome measures the change in MFIS total score from baseline to Week 4. Negative change values represent improvement in fatigue.
Time frame: Baseline to End of Treatment (week 4)
Change in MFIS at Follow up
MFIS is a 21-item patient-reported fatigue impact scale (range 0-84; higher scores indicate greater fatigue). This outcome assesses change in total MFIS score from baseline to follow-up assessment (Week 8).
Time frame: Baseline to Follow-up (week 8)
Change in Fatigue Severity Scale (FSS)
The Fatigue Severity Scale (FSS) is a 9-item questionnaire assessing the severity and functional impact of fatigue on daily activities. Each item is scored 1-7; the final score is the mean of all items, with higher scores indicating more severe fatigue. This outcome reflects change in FSS score from baseline to Week 4 and Week 8.
Time frame: Baseline to End of Treatment (week 4) and Follow-up (week 8)
Change in Visual Analogue Scale for Mental Fatigue (VAS-MF)
VAS-MF is a single-item 0-100 mm visual analogue scale measuring perceived mental fatigue. Higher values indicate greater fatigue. This outcome assesses change in VAS-MF score from baseline to Week 4 and Week 8
Time frame: Baseline to End of Treatment (week 4) and Follow-up (week 8)
Change in PROMIS Fatigue Score
The PROMIS Fatigue Short Form assesses self-reported fatigue and its interference with daily functioning. Scores are reported as standardized T-scores (mean 50, SD 10); higher scores indicate greater fatigue. This outcome measures change in PROMIS Fatigue from baseline to Week 4 and Week 8.
Time frame: Baseline to End of Treatment (week 4) and Follow-up (week 8)
Change in Neuro-QoL Fatigue
Neuro-QoL Fatigue evaluates the impact of fatigue on quality of life in neurological conditions. Scores are converted to T-scores (mean 50, SD 10), with higher scores indicating worse fatigue-related QoL. This outcome measures change in Neuro-QoL Fatigue from baseline to Week 4 and Week 8
Time frame: Baseline to End of Treatment (week 4) and Follow-up (week 8)
Change in Symbol Digit Modalities Test (SDMT)
The SDMT is a widely used measure of information processing speed. The score reflects the number of correct symbol-digit matches completed in 90 seconds, with higher scores indicating better cognitive performance. This outcome assesses change in SDMT score from baseline to Week 4 and Week 8.
Time frame: Baseline to End of Treatment (week 4) and Follow-up (week 8)
Rate of Change in Daily Fatigue Severity (DFS) During the Treatment Period
Daily Fatigue Severity (DFS) is assessed using a repeated self-reported rating of fatigue severity. Participants respond to the question "How fatigued do you feel today?" using a 7-point Likert scale, where higher scores indicate greater fatigue. This outcome assesses the rate of change in DFS across the treatment period to characterize longitudinal changes in daily fatigue.
Time frame: Baseline through End of treatment (week 4)
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