Cognitive Markers in Prodromal MS

Intra-Individual Variability in Cognitive Performance as a Marker of Prodromal Disability in MS

The focus of this work is the evaluation of a measure of cognitive functioning- intra-individual variability (IIV) - derived from a computer-based continuous reaction time (RT) task (Cogstate) as an early marker of prodromal MS.

This study is a prospective observational clinical study, where the researchers will recruit adults with early MS (n=60) to complete a cognitive assessment and an optional gait assessment using Runscribe and G-sensor. Thirty-five [35] participants will also have a single 60-minute investigational MRI combined with 20 minutes of simultaneous tDCS. The MRI will repeat the protocol from the researchers' current study (ClinicalTrials.gov Identifier: NCT03564496, IRB i18-00548) using simultaneous transcranial direct current stimulation (tDCS) during the imaging acquisition.

Inclusion Criteria:

• Ages 23-59 years old (inclusive)
• Prodromal MS (defined by radiologically isolated syndrome ≤ 6 months from first MRI or clinically isolated syndrome ≤ 3 months from first clinical event)

Exclusion Criteria:

• Below average estimated premorbid cognitive functioning (based on WRAT-4 reading recognition standard z-score < 85).
• Presence of severe cognitive impairment (based on SDMT age normative z-score <-3.0).
• Primary psychiatric disorder that would influence ability to participate.
• Current uncontrolled seizure disorder.
• Current substance abuse disorder.
• History of head trauma in the past year (e.g., head injury, brain surgery) or medical device implanted in the head (such as Deep Brain Stimulator) or in the neck (such as a Vagus Nerve Stimulator).
• Pregnant or breastfeeding

Additional Exclusion Criteria for tDCS-MRI Participants

• Extreme claustrophobia
• Any skin disorder/sensitive skin (e.g., eczema, severe rashes), blisters, open wounds, burn including sunburns, cuts or irritation, or other skin defects which compromise the integrity of the skin at or near stimulation locations (where electrodes are placed)
• Treatment for a communicable skin disorder currently or over the past 12 months
• Have any irremovable piercings, metallic based-tattoos, or MRI-contraindicated implants (e.g. pacemakers and defibrillators)