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

2019 ◽  
Author(s):  
Nicko Jackson ◽  
Scott R. Cole ◽  
Bradley Voytek ◽  
Nicole C. Swann
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Beta Phase ◽  
Beta Oscillations ◽  
Non Invasive ◽  
Scalp Eeg ◽  
Phase Amplitude ◽  
Beta Frequency ◽  
Intracranial Recordings ◽  
Beta Oscillation

AbstractNeural 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 non-invasive 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.

scholarly journals Nonsinusoidal oscillations underlie pathological phase-amplitude coupling in the motor cortex in Parkinson’s disease

2016 ◽  
Author(s):  
Scott R. Cole ◽  
Erik J. Peterson ◽  
Roemer van der Meij ◽  
Coralie de Hemptinne ◽  
Philip A. Starr ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Motor Cortex ◽  
Field Potential ◽  
Synaptic Activity ◽  
Motor Deficit ◽  
Beta Oscillations ◽  
High Gamma ◽  
Phase Amplitude

AbstractParkinson’s disease (PD) is associated with abnormal beta oscillations (13-30 Hz) in the basal ganglia and motor cortex (M1). Recent reports show that M1 beta-high gamma (50-200 Hz) phase-amplitude coupling (PAC) is exaggerated in PD and is reduced following acute deep brain stimulation (DBS). Here we analyze invasive M1 electrocorticography recordings in PD patients on and off DBS, and in isolated cervical dystonia patients, and show that M1 beta oscillations are nonsinusoidal, having sharp and asymmetric features. These sharp oscillatory beta features underlie the previously reported PAC, providing an alternative to the standard interpretation of PAC as an interaction between two distinct frequency components. Specifically, the ratio between peak and trough sharpness is nearly perfectly correlated with beta-high gamma PAC (r = 0.96) and predicts PD-related motor deficit. Using a simulation of the local field potential, we demonstrate that sharp oscillatory waves can arise from synchronous synaptic activity. We propose that exaggerated beta-high gamma PAC may actually reflect such synchronous synaptic activity, manifesting as sharp beta oscillations that are “smoothed out” with DBS. These results support the “desynchronization” hypothesis of DBS wherein DBS counteracts pathological synchronization throughout the basal ganglia-thalamocortical loop. We argue that PAC can be influenced by more than one mechanism. In this case synaptic synchrony, rather than the often assumed spike-field coherence, may underlie exaggerated PAC. These often overlooked temporal features of the oscillatory waveform carry critical physiological information about neural processes and dynamics that may lead to better understanding of underlying neuropathology.

scholarly journals Synchronised spiking activity underlies phase amplitude coupling in the subthalamic nucleus of Parkinson’s disease patients

2018 ◽  
Author(s):  
Anders Christian Meidahl ◽  
Christian K.E. Moll ◽  
Bernadette van Wijk ◽  
Alessandro Gulberti ◽  
Gerd Tinkhauser ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Subthalamic Nucleus ◽  
Single Unit ◽  
Closed Loop ◽  
Beta Phase ◽  
Frequency Range ◽  
Phase Amplitude ◽  
Deep Brain ◽  
Spiking Activity

AbstractBoth phase-amplitude coupling (PAC) and beta-bursts in the subthalamic nucleus have been significantly linked to symptom severity in Parkinson’s disease (PD) in humans and emerged independently as competing biomarkers for closed-loop deep brain stimulation (DBS). However, the underlying nature of subthalamic PAC is poorly understood and its relationship with transient beta burst-events has not been investigated. To address this, we studied macro- and micro electrode recordings of local field potentials (LFPs) and single unit activity from 15 hemispheres in 10 PD patients undergoing DBS surgery. PAC between beta phase and high frequency oscillation (HFO) amplitude was compared to single unit firing rates, spike triggered averages, power spectral densities and phase-spike locking, and was studied in periods of beta-bursting. We found a significant synchronisation of spiking to HFOs and correlation of mean firing rates with HFO-amplitude when the latter was coupled to beta phase (i.e. in the presence of PAC). In the presence of PAC, single unit power spectra displayed peaks in the beta and HFO frequency range and the HFO frequency was correlated with that in the LFP. Finally, PAC significantly increased with beta burst-duration. Our findings offer new insight in the pathology of Parkinson’s disease by providing evidence that subthalamic PAC reflects the locking of spiking activity to network beta oscillations and that this coupling progressively increases with beta-burst duration. These findings suggest that beta-bursts capture periods of increased subthalamic input/output synchronisation in the beta frequency range and have important implications for therapeutic closed-loop DBS.Significance statementIdentifying biomarkers for closed-loop deep brain stimulation (DBS) has become an increasingly important issue in Parkinson’s Disease (PD) research. Two such biomarkers, phase–amplitude coupling (PAC) and beta-bursts, recorded from the implanted electrodes in subthalamic nucleus in PD patients, correlate with motor impairment. However, the physiological basis of PAC, and it relationship to beta bursts, is unclear. We provide multiple lines of evidence that PAC in the human STN reflects the locking of spiking activity to network beta oscillations and that this coupling progressively increases with the duration of beta-bursts. This suggests that beta-bursts capture increased subthalamic input/output synchronisation and provides new insights in PD pathology with direct implications for closed-loop DBS therapy strategies.

scholarly journals Effect of levodopa on electroencephalographic biomarkers of the parkinsonian state

2019 ◽  
Vol 122 (1) ◽  
pp. 290-299 ◽  
Author(s):  
Andrew M. Miller ◽  
Svjetlana Miocinovic ◽  
Nicole C. Swann ◽  
Sheila S. Rajagopalan ◽  
David M. Darevsky ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Voluntary Movement ◽  
Motor Impairment ◽  
Body Part ◽  
Dopaminergic Therapy ◽  
Scalp Eeg ◽  
New Findings ◽  
Phase Amplitude ◽  
Motor Improvement

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.

Analyses of conditions for generating beta oscillations in the Cortex–Subthalamic Nucleus–Globus Pallidus model

2020 ◽  
Vol 34 (13) ◽  
pp. 2050134 ◽  
Author(s):  
Jing-Yi Zhao ◽  
Quan-Sheng Liu ◽  
Yuan-Hong Bi ◽  
Zhuo-Qin Yang
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Globus Pallidus ◽  
Subthalamic Nucleus ◽  
Stability Boundary ◽  
Inhibitory Neurons ◽  
Beta Oscillations ◽  
Connection Weight ◽  
The Stability ◽  
Beta Oscillation

Analyzing the conditions for generating beta oscillation in basal ganglia plays a key role in understanding the mechanism of Parkinson’s disease (PD). In this paper, we consider a Cortex–STN–GPe model, which consists of the external segment of globus pallidus (GPe), subthalamic nucleus (STN) and cortex including excitatory and inhibitory neurons. We obtain the stability boundary conditions for the model through theoretical analyses, and discuss the influence of two inputs to cortex and GPe on oscillations by numerical simulation. Our results reveal that the model can oscillate for large connection weight between STN and GPe, much larger input to the cortex, and most input values to the GPe. Furthermore, the effects of parameters in the cortical circuit on the amplitude and frequency of the beta oscillation are analyzed. We show that larger delay and larger firing rate of excitatory and inhibitory neurons in the cortex make the model oscillate easily. We hope that our results will be helpful for further understanding the mechanisms of beta oscillations in the treatment of Parkinson’s disease and may apply to some studies of neural oscillations.

scholarly journals Perspective: Phase Amplitude Coupling–Based Phase–Dependent Neuromodulation in Parkinson’s Disease

2020 ◽  
Vol 14 ◽  
Author(s):  
Brian Y. Hwang ◽  
Yousef Salimpour ◽  
Yohannes K. Tsehay ◽  
William S. Anderson ◽  
Kelly A. Mills
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Phase Amplitude

Synchronized cortico-subthalamic beta oscillations in Parkin-associated Parkinson’s disease

2015 ◽  
Vol 126 (11) ◽  
pp. 2241-2243 ◽  
Author(s):  
Christian K.E. Moll ◽  
Carsten Buhmann ◽  
Alessandro Gulberti ◽  
Ulrich Fickel ◽  
Monika Poetter-Nerger ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Beta Oscillations
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