Effect of levodopa on electroencephalographic biomarkers of the parkinsonian state

Abstract

The objective of this study was to evaluate proposed electroencephalographic (EEG) biomarkers of Parkinson’s disease (PD) and test their correlation with motor impairment in a new, well-characterized cohort of PD patients and controls. Sixty-four-channel EEG was recorded from 14 patients with rigid-akinetic PD with minimal tremor and from 14 age-matched healthy controls at rest and during voluntary movement. Patients were tested off and on medication during a single session. Recordings were analyzed for phase-amplitude coupling over sensorimotor cortex and for pairwise coherence from all electrode pairs in the recording montage (distributed coherence). Phase-amplitude coupling and distributed coherence were found to be elevated Off compared with On levodopa, and their reduction was correlated with motor improvement. In the Off medication state, phase-amplitude coupling was greater in sensorimotor contacts contralateral to the most affected body part and reduced by voluntary movement. We conclude that phase-amplitude coupling and distributed coherence are cortical biomarkers of the parkinsonian state that are detectable noninvasively and may be useful as objective aids for management of dopaminergic therapy. Several analytic methods may be used for noninvasive measurement of abnormal brain synchronization in PD. Calculation of phase-amplitude coupling requires only a single electrode over motor cortex. NEW & NOTEWORTHY Several EEG biomarkers of the parkinsonian state have been proposed that are related to abnormal cortical synchronization. We report several new findings in this study: correlations of EEG markers of synchronization with specific motor signs of Parkinson’s disease (PD), and demonstration that one of the EEG markers, phase-amplitude coupling, is more elevated over the more clinically affected brain hemisphere. These findings underscore the potential utility of scalp EEG for objective, noninvasive monitoring of medication state in PD.

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies—A Systematic Review

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Washout of chronic therapeutic deep brain stimulation increases cortical phase-amplitude coupling

“…Our findings provide support for cortical phase-amplitude coupling as a marker of pathological synchronization in Parkinson's disease that responds to deep brain stimulation therapy, and is correlated with symptomatic improvement. In a prior study, levodopa induced PAC reduction was more closely related to bradykinesia than rigidity [6], which may reflect differences in severity of specific motor signs between the two groups. We also provide evidence for the first time that DBS-induced changes in cortical synchronization in Parkinson's disease may be detected using scalp EEG, offering implications for the use of noninvasive recording techniques in the development of control signals for closed-loop DBS paradigms.…”