Dopaminergic medication reduces interhemispheric hyper-synchronization in Parkinson's disease

Or Koren, Ronny P. Bartsch, Zoya Katzir, Uri Rosenblum, Sharon Hassin-Baer, Rivka Inzelberg, Meir Plotnik

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Introduction: We previously reported on interhemispheric cortical hyper synchronization in PD. The aim of the present study was to address the hypothesis that increased interhemispheric cortical synchronization in PD is related to dopamine deficiency and is correlated with motor function. Methods: We studied participants with PD and characterized cortical synchronization with reference to brain regions. Electroencephalography (EEG) was recorded from 20 participants with PD while OFF and ON their dopaminergic medications (two separate visits), during quiet standing and straight-line walking. Cortical interactions in the theta, alpha, beta, and gamma brain wave frequency bands were evaluated using interhemispheric phase synchronization (inter-PS). Results: Inter-PS values were found to be significantly higher during the OFF state as compared to the ON state in standing and walking trials for theta, alpha and beta bands. In addition, inter-PS reduction from OFF to ON was associated with mobility improvement evaluated by the Timed Up and Go test, and with daily levodopa equivalent dose across individuals. Higher differences in inter-PS values between OFF and ON states were evident mainly in the occipital-parietal cortex. Conclusions: Persons with PD have increased inter-PS during the OFF state compared to their ON state, and this increase in inter-PS is associated with the clinical improvement between OFF and ON. We speculate that these findings, together with previous evidence of higher inter-PS in PD as compared to healthy older adults, reflect neuronal processes consequential to asymmetric subcortical dopamine deficiency.

Original languageEnglish
Pages (from-to)39-46
Number of pages8
JournalParkinsonism and Related Disorders
StatePublished - Apr 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd


This study was supported in part by the Israel Science Foundation (ISF) grant # 1657–16 and the Israeli Ministry of Health grant # 3000-14527 . The authors thank the participants for their time and efforts, Dr. Jan W. Kantelhardt and Mr. Moritz Günther for their advice on electroencephalography analysis and Mr. Amihai Gottlieb for technical support. This study was supported in part by the Israel Science Foundation ( ISF ) grant # 1657–16 and the Israeli Ministry of Health grant # 3000-14527.

FundersFunder number
Israel Science Foundation1657–16
Ministry of Health, State of Israel3000-14527


    • Electroencephalography
    • Parkinson's disease
    • Phase synchronization


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