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Tremor and Dysmetria in Multiple Sclerosis: A Neurophysiological Study
S H Alusi1, A Macerollo2, Colum D MacKinnon3
1Department of Neurology, The Walton Centre NHS Foundation Trust, Liverpool, UK.
Tremor and Other Hyperkinetic Movements (New York, N.Y.)
|August 16, 2021
Summary
Multiple sclerosis (MS) patients with dysmetria show delayed central sensory and motor conduction times. These delays, linked to demyelination, disrupt motor timing and contribute to MS-related movement disorders.
Area of Science:
- Neuroscience
- Neurology
- Neuroimmunology
Background:
- The exact causes of tremor and dysmetria in multiple sclerosis (MS) remain unclear.
- Abnormal brain network oscillations are implicated in tremor and intention dysmetria.
- Delayed central motor conduction times are common in ataxias and may contribute to MS dysmetria.
Purpose of the Study:
- This research investigated the role of central conduction delays in the development of tremor and/or dysmetria in individuals with MS.
Main Methods:
- The study included 23 MS participants categorized by movement disorder status.
- Median nerve somatosensory evoked potentials (SEPs), transcranial magnetic stimulation (TMS), and stretch reflexes were employed.
- These methods assessed sensory and motor conduction times.
Main Results:
- Participants with dysmetria, irrespective of tremor, exhibited significantly delayed central sensory conduction times.
- Individuals with dysmetria also showed delayed TMS-evoked muscle responses and long-latency stretch reflexes.
- These delays were not observed in participants with pure tremor.
Conclusions:
- Dysmetria in MS is linked to central sensory or motor pathway conduction delays, or both.
- These delays likely disrupt muscle activation timing and contribute to dysmetria.
- The findings suggest that conduction delays in MS are associated with increased demyelination.
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