Changes in non-oscillatory features of the cortical sensorimotor rhythm in Parkinson’s disease across age

Parkinson’s disease (PD) is associated with changes in neural activity in the sensorimotor alpha and beta bands. Using magnetoencephalography (MEG), we investigated the role of spontaneous neuronal activity within the somatosensory cortex in a large cohort of early-to mid-stage PD patients (N = 78) and age- and sex matched healthy controls (N = 60) using source reconstructed resting-state MEG. We quantified features of the time series data in terms of oscillatory alpha power, beta power, and 1/f broadband characteristics using power spectral density, and also characterised transient beta burst events in the time-domain signals. We examined the relationship between these signal features and the patients’ disease state, symptom severity, age, sex, and cortical thickness. PD patients and healthy controls differed on PSD broadband characteristics, with PD patients showing a steeper 1/f exponential slope and higher 1/f offset. PD patients further showed a steeper age-related decrease in the burst rate. Out of all the signal features of the sensorimotor activity, only burst rate was associated with increased severity of bradykinesia. Our study shows that general non-oscillatory features (broadband PSD slope and offset) of the sensorimotor signals are related to disease state and oscillatory burst rate scales with symptom severity in PD. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Supported by the Swedish Foundation for Strategic Research (SBE 13-0115). The NatMEG facility is supported by Knut & Alice Wallenberg (KAW2011.0207) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Etikprovningsnamden Stockholm, DNR 2019-00542 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data will be made available fall 2022.