Electrophysiology in Functional Movement Disorders: An Update

Area of Science:

• Neurology
• Neurophysiology

Background:

• Functional movement disorders (FMD) present a complex diagnostic and therapeutic challenge.
• FMDs manifest with diverse symptoms including tremors, dystonia, and gait disturbances.
• Electrophysiological studies are increasingly utilized in FMD evaluation.

Purpose of the Study:

• To review the utility of electrophysiological studies in diagnosing functional movement disorders.
• To explore how these tests differentiate FMD from organic movement disorders.

Main Methods:

• A comprehensive literature search was conducted across major databases (MEDLINE, Google Scholar, Web of Science, Scopus).
• Search terms included relevant Medical Subject Headings (MeSH) for articles published from 1970 to 2022.
• A review of 79 relevant articles focused on 26 studies with electrophysiological data.

Main Results:

• Multichannel surface electromyography can identify variability and distractibility in functional tremors.
• Specific electrophysiological findings like Bereitschaftspotential and altered blink reflex recovery cycles aid in diagnosis.
• Co-contraction testing and plasticity assessments help distinguish functional from organic dystonia.

Conclusions:

• Electrophysiological tests provide valuable objective data to supplement clinical assessments.
• These studies are crucial for differentiating functional movement disorders from organic etiologies.