Category: Neurophysiology (Non-PD)
Objective: This study aim of highlighting the difference in term of clinical characteristics, physical examination, risk factors, psychiatric comorbidity, and results of the neurophysiology test between laboratory-supported FT and organic tremor.
Background: Functional (psychogenic) movement disorders (FMD) are not uncommon, and mainly tremor. Functional tremor (FT) poses a challenge in clinical diagnosis because of the great variability in clinical phenotypes which mimic others. A mistake in its recognition may have important consequences for the patients.
Method: 12 new patients with clinical FT were assessed by a movement disorders specialist at a Chulalongkorn hospital between February 2017 and October 2019. Demographic and presenting features were reviewed, and confirmed by our Movement Disorders Neurophysiology Laborator.
Results: Of these 12 patients, 50% (6 patients) were laboratory-supported FT. The female to male ratio was higher in FT (5:1 vs 1:1). No difference in age of onset, disease duration ,and psychiatric comorbidity were observed ,but precipitation by minor injuries, and stressful life events were commonly reported in FT. A distinct feature of patients with FT was the predominant involvement of the unilateral dominant limb, postural and task-specific tremor with dystonic posture, while bilateral were found in only patients with organic tremor. The latter were laboratory-diagnosed EPT (4 patients), PD(1), OT(1). Several clues, including incongruous symptoms, inconsistency, distractibility, suggestibility, entrainment of symptoms, and ballistic movement were observed in both group with relatively frequent in FT.
Conclusion: A combination of physical test revealed significant differences on a group level, but there was no single test with sensitivity and specificity for distinguishing. Our data also re-define electrodiagnostic criteria in FT.
To cite this abstract in AMA style:
m.s Virameteekul, m.s Panyakaew, m.r Bhidayasiri. Feasibility of neurophysiological testing for differential diagnosis of functional tremor [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/feasibility-of-neurophysiological-testing-for-differential-diagnosis-of-functional-tremor/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/feasibility-of-neurophysiological-testing-for-differential-diagnosis-of-functional-tremor/