A SCOPING REVIEW ON THE NEURAL ELECTROPHYSIOLOGICAL CORRELATES OF GAIT IN PARKINSON’S DISEASE
Creators: name: Gennaro, Federico
name: Ma, Lei
name: Osuna-Garcia, Antonia
name: Cross, Katy
Publisher: name: Open Science Framework
Year: 2023
Subjects: subject: Medicine and Health Sciences
subject: Medical Specialties
subject: Neurology
subject: ambulation
subject: ECoG
subject: EEG
subject: Electrocorticography
subject: Electroencephalography
subject: gait
subject: gait initiation
subject: human locomotion
subject: intracranial EEG
subject: mobile brain-body imaging
subject: movement disorsders
subject: Parkinson’s Disease
subject: walking

description: Gait impairment is a cardinal feature of Parkinson’s disease (PD), along with slowness (bradykinesia), stiffness (rigidity) and tremor. Gait dysfunction is often poorly responsive to treatment and becomes a major contributor to morbidity and mortality. Understanding neurophysiological mechanisms to develop improved treatment strategies has therefore been identified as a priority in PD research. Gait impairments are heterogeneous and attributed to a number of non-mutually exclusive pathophysiologic mechanisms. Dopamine loss in the basal ganglia is thought to lead to reduction in gait automaticity and a greater reliance on goal directed or voluntary motor control circuits. Abnormal basal ganglia output may also result in deranged brainstem locomotor circuit function. An overreliance on cortical/voluntary control of gait may lead to an increased susceptibility to interference and sudden gait breakdown (e.g., freezing of gait). Pathology affecting brainstem locomotor regions such as the pedunculopontine nucleus may also contribute to impaired postural control and coordination of postural changes and gait. Animal models (largely quadrupeds), clinical studies and human neuroimaging techniques examining brain activity in the supine position at rest or during such as virtual reality, motor imagery and gait-related upper extremity movements have been integral to our current understanding of gait impairment in PD. However, it is unclear how well these conditions accurately reflect human bipedal locomotion and therefore brain recordings in patients during gait are essential to further elucidate the pathophysiology of gait impairment in PD. Recent advances in technology and analysis strategies provide the ability to record human brain activity during ambulation. In this scoping review, we review studies of mobile brain imaging during gait tasks in Parkinson’s disease to provide a summary of what is known about electrophysiological neural activity during gait, identify areas for systematic review to inform potential neuromodulation targets, and identify gaps in knowledge for future investigation. We limit our review to electrophysiological studies which have high temporal resolution (i.e., EEG, ECoG, and LFP) suited to explore dynamic changes associated with continuous walking or gait initiation. The aim of this scoping review is to provide an overview of what is known about neural correlates of gait in PD and identify knowledge gaps and areas for future research to inform neuromodulation targets. The review will answer the following questions: 1) What is known about the neural electrophysiological correlates of continuous walking and gait initiation in PD? 2) What is known about how neural electrophysiological correlates of continuous walking and gait initiation change with treatment (pharmacologic, neuromodulation, behavioral, rehabilitation, exercise)?