Slower Reaction Time May Reveal Thinking Changes in MS

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Key Takeaway

Slower reaction times during a simple symbol-digit test are a clear, easy-to-measure sign of thinking changes in people with MS.

What They Found

Researchers used an EEG-friendly version of the Symbol Digit Modalities Test (SDMT), a quick test where you match symbols to numbers, to study thinking in people with MS. They measured brain waves (called event-related potentials, or ERPs) and how fast people pressed buttons (reaction time, RT) while doing the test. A particular brain wave peak (called P5) happened later in people with MS than in healthy people, which means their brains took longer to process the test. However, the P5 delay did not reliably tell who had noticeable thinking problems and who did not. Reaction time was strongly linked to SDMT scores: people who took longer to respond tended to do worse on the standard test, making RT a more useful sign of thinking difficulties than the P5 brain wave timing.

Who Should Care and Why

People with MS and their caregivers should care because the study suggests a simple measure—how quickly someone responds during a short test—can show thinking changes that affect daily life, like slower decision-making when cooking or driving. Neurologists and therapists can use reaction time as an easy, low-cost way to monitor thinking changes over time, similar to timing how fast someone walks to check balance. Caregivers can watch for slower responses in conversation or tasks as a clue that cognitive support or adjustments might help. Researchers and clinicians may still use brain recordings (EEG) to learn about early brain changes, but for practical day-to-day checks, reaction time is more immediately useful. Overall, this work points to an accessible method to track thinking speed, which can guide when to ask for more help or change treatment plans.

Important Considerations

The study found the P5 brain wave was slower in MS, but that measure could not tell who had clear cognitive problems yet—it may only pick up very early brain changes. The test and EEG were done in a lab setting, so results might be different in real-life situations or with different equipment. Because this is one study, reaction time should be used as one helpful sign among others (like memory or daily function reports), not as the only proof of cognitive change.

AI-generated summary — for informational purposes only, not medical advice

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Specific Symptoms MS Diagnostics Early Research

Article Topics:

Cognitionelectroencephalographymultiple sclerosisreaction timesymbol digit modalities test

Whether you’ve recently been diagnosed with Multiple Sclerosis (MS) or are seeking to broaden your understanding of this complex, neurodegenerative disease, navigating the latest research can feel overwhelming. Studies published in respected medical journals like Multiple sclerosis (Houndmills, Basingstoke, England) often range from early-stage, exploratory work to advanced clinical trials. These evidence-based findings help shape new disease-modifying therapies, guide symptom management techniques, and deepen our knowledge of MS progression.

However, not all research is created equal. Some clinical research studies may have smaller sample sizes, evolving methodologies, or limitations that warrant careful interpretation. For a more comprehensive, accurate understanding, we recommend reviewing the original source material—accessible via the More Details section above—and consulting with healthcare professionals who specialize in MS care.

By presenting a wide range of MS-focused studies—spanning cutting-edge treatments, emerging therapies, and established best practices—we aim to empower patients, caregivers, and clinicians to stay informed and make well-informed decisions when managing Multiple Sclerosis.

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