Standardized P-VEEG recordings and SEPs show polygraphic patterns in 73 pediatric patients with hyperkinetic movement disorders.

BackgroundHyperkinetic movement disorders (MDs) in children, including tremor, myoclonus, dystonia, chorea, and tics, often present with overlapping or evolving clinical features, making classification based on observation alone challenging. Neurophysiological techniques such as video-EEG polymyography (P-VEEG) and somatosensory evoked potentials (SEPs) may provide objective markers to improve diagnostic accuracy, yet their application in pediatric populations remains limited.ObjectiveTo describe the polygraphic characteristics of hyperkinetic MDs in a large pediatric cohort and to assess whether specific EMG patterns can support movement disorder classification beyond clinical inspection.MethodsSeventy-three patients with pediatric-onset hyperkinetic MDs underwent standardized P-VEEG recordings and SEPs at Besta Neurological Institute between January and October 2024. EMG activity was recorded from antagonist muscle pairs during rest, posture maintenance, and specific tasks according to age. Polygraphic findings were compared with clinical diagnoses. Associations between EMG patterns and clinical variables were analyzed using Chi-square tests and regression analyses.ResultsMean age at MD onset was 9.4 ± 6.1 years and mean age at recording was 13.5 ± 5.1 years. Polygraphic analysis identified four distinct EMG patterns: (i) regular rhythmic oscillatory pattern (RRO), consistent with tremor, in 40 patients (56%); (ii) repetitive myoclonic pattern (RM) in 11 (15%); (iii) complex mixed repetitive pattern (CR) in 9 (12%); and (iv) complex non-rhythmic pattern (CNR), encompassing chorea, dystonia, tics and other dyskinesias, in 11 (15%). Significant differences among repetitive patterns were observed in rhythmicity (p