Objective: To assess the diagnostic accuracy of various electrophysiological tests in differentiating functional tremor from organic tremor.

Background: Functional tremor is the most common phenotype of functional movement disorders. Delayed diagnosis can negatively impact patient outcomes, highlighting the need for early and accurate identification. Electrophysiological testing serves as a valuable tool in diagnosing functional tremor, particularly in cases where clinical assessment alone is inconclusive. To synthesize the diagnostic accuracy of different electrophysiological tests, we performed a systematic review and meta-analysis.

Method: A systematic search of the PubMed and Scopus databases was conducted from inception to February 2025. Study quality was evaluated using the QUADAS-2 tool. Electrophysiological tests were categorized into single-test modalities, including spontaneous tests, task-related tests, and coherence tests, as well as battery tests that integrate multiple single tests. Pooled sensitivity and specificity, both overall and by test subgroup, were estimated using a random-effects univariate model.

Results: Ten studies comprising 37 test arms, categorized into 14 test subgroups, were included. The overall pooled sensitivity and specificity were 0.63 (95% CI: 0.51 – 0.75) and 0.93 (95% CI: 0.91 – 0.95), respectively. Sensitivity and specificity for single-test subgroups ranged from 30% to 100% and 68% to 100%, respectively, while battery-test subgroups demonstrated sensitivity and specificity ranging from 94% to 100% and 93% to 98%, respectively. Among individual single tests, those measuring frequency shift and frequency peak width during mental task distraction exhibited a 95% confidence interval lower bound exceeding 80% for both sensitivity and specificity. Both battery tests also met this criterion.

Conclusion: A range of electrophysiological tests demonstrate utility in differentiating functional tremor from organic tremor, with varying levels of diagnostic accuracy. Certain single tests and battery tests exhibit high sensitivity and specificity, underscoring their potential role in clinical decision-making.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/electrophysiology-in-distinguishing-functional-tremor-from-organic-tremor-a-systematic-review-and-meta-analysis-of-diagnostic-accuracy/