Objective: To define the differences in characteristics on electrophysiological tremor analysis between the tremor-dominant (TD) and Postural Instability and Gait Difficulty (PIGD) phenotype.
Background: Based on motor phenotype, Parkinson’s disease is classified into tremor-dominant (TD) and postural instability and gait difficulty (PIGD) subtypes. These phenotypes differ in clinical features, disease progression, and effects on motor function and quality of life. However, differences in tremor spectral characteristics and electromyographic (EMG) activation patterns remain unclear. Clarifying these differences may improve understanding of pathophysiology and support objective phenotypic stratification.
Method: Patients with Parkinson’s disease were classified as TD or PIGD using clinical criteria. Electrophysiological analysis included surface EMG and accelerometry during rest, posture, and action. Spectral analysis extracted peak frequency and half-width (HW) reflecting oscillation stability. EMG patterns were categorized as alternating, co-contraction, or mixed. Groups were compared using statistical tests.
Results: A total of 151 patients were included (90 TD and 61 PIGD). Peak frequencies at rest and during posture did not differ significantly between the groups. However, HW of the TD group was significantly lower than that of the PIGD group (0.75 ± 0.08 vs. 0.86 ± 0.19; p < 0.05), suggesting a more stable oscillation in the TD. ROC analysis showed modest discriminative ability of HW for distinguishing TD from PIGD (AUC = 0.66, p=0.001). Using a cut-off of 0.75, HW yielded 67.2% sensitivity and 51.1% specificity for identifying the TD phenotype. In addition, the proportion of alternating EMG activation patterns was significantly higher in the TD group (91.1% vs. 77%; p=0.02). The combined model including half-width and EMG activation pattern demonstrated slightly improved discrimination for identifying the TD phenotype (AUC = 0.69, p < 0.001).
Conclusion: TD patients showed a narrower oscillatory spectrum and more frequent alternating activation patterns, suggesting a more stable central oscillatory mechanism. In contrast, the broader spectrum in PIGD may reflect involvement of more complex neural networks beyond basal ganglia circuits. These findings support electrophysiological analysis as a quantitative tool for phenotypic stratification in Parkinson’s disease.
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2. Dirkx MF, Zach H, Bloem BR, Hallett M, Helmich RC. The nature of postural tremor in Parkinson disease. Neurology. 2018;90(13):e1095-e1103.
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To cite this abstract in AMA style:
L. Truong, H. Vu, Y. Vu, Y. Nguyen, L. Nguyen. Electrophysiological Tremor Analysis In Tremor-Dominant And Postural Instability And Gait Difficulty Phenotypes Of Parkinson’s Disease [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/electrophysiological-tremor-analysis-in-tremor-dominant-and-postural-instability-and-gait-difficulty-phenotypes-of-parkinsons-disease/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/electrophysiological-tremor-analysis-in-tremor-dominant-and-postural-instability-and-gait-difficulty-phenotypes-of-parkinsons-disease/