Characteristics of Beta Waveform Shape in Parkinson’s Disease Detected with Scalp Electroencephalography

Abstract

Neural activity in the beta frequency range (13-30 Hz) is excessively synchronized in Parkinson's Disease (PD). Previous work using invasive intracranial recordings and non-invasive scalp electroencephalography (EEG) has shown that correlations between beta phase and broadband gamma amplitude (i.e., phase-amplitude coupling) are elevated in PD, perhaps a reflection of this synchrony. Recently, it has also been shown, in invasive human recordings, that nonsinusoidal features of beta oscillation shape also characterize PD. Here we show that these features of beta waveform shape also distinguish PD patients on and off medication using noninvasive recordings in a dataset of 15 PD patients with resting scalp EEG. Specifically, beta oscillations over sensorimotor electrodes in PD patients off medication had greater sharpness asymmetry and steepness asymmetry than on medication (sign rank, p=0.006, p=0.003 respectively). We also showed that beta oscillations over sensorimotor cortex most often had a canonical shape and that using this prototypical shape as an inclusion criterion increased the effect size of our findings. Together our findings suggest that novel ways of measuring beta synchrony that incorporate waveform shape could improve detection of PD pathophysiology in non-invasive recordings.

A framework for quantifying the coupling between brain connectivity and heartbeat dynamics: Insights into the disrupted network physiology in Parkinson’s disease

“…In our results we observed a decrease in the coupling of cardiac sympathetic activity with brain connectivity measured in the alpha and gamma bands. EEG studies have revealed significant changes in the alpha-gamma range in PD, with reduced connectivity in alpha-beta bands and increased connectivity in the gamma band (12), but also aberrant cortical synchronization in the beta band (17,18). It remains to be confirmed whether our results relate to the repeatedly reported changes in brain connectivity in PD, including subcortical structures.…”

“…In recent years, PD has been recognized as a condition that affects physiology at a network level, rather than just a focal brain region pathology (15,16). One of the physiological signatures of PD are the aberrant changes in brain connectivity, whose origin remains to be understood (17,18). We propose a new framework to study brain-heart interactions by quantifying the relationship between brain connectivity and estimators of cardiac sympathetic and parasympathetic activities.…”