Effect of ageing and Parkinson's disease on brain cortical activity during walking: association with cognition and visual sampling

Abstract

Introduction: To maintain an independent and mobile lifestyle we are often required to navigate complex and hazardous environments that present various visual, cognitive and motor challenges. The ability to visually perceive, cognitively process and formulate appropriate locomotor plans for navigation can be compromised both with ageing and in the presence of neurodegenerative disorders such as Parkinson's disease (PD). Increased attentional resources are required for multitasking and complex/adaptive gait (such as negotiating obstacles and cued gait) and accordingly increased cortical activity is observed in line with amplified cognitive and sensory demands. Freezing of gait (FOG) is associated with unsafe gait and reduced cortical (parietal) activity. Implementation of external cues can both ameliorate and aggravate FOG depending on walking condition and cue modality. Our understanding of the neural correlates and mechanistic pathways underpinning human locomotion is limited. Investigating the networks involved and the changes that occur both with ageing and pathology are essential to: understand changes in mobility; appropriately tailor the design of environmental modifications; and enhance the effectiveness of therapy and interventions. The aims of this research project are to (i) investigate the effects of aging and PD (with and without FOG) on brain cortical activity during complex walking; (ii) better understand the interaction between brain cortical activity, visual sampling and cognitive resources during performance of complex walking tasks. Methods: The following participants will be recruited: 15 young adults, 15 old adults, 15 people with mild to moderate PD (with and without FOG). All participants will be asked to attend the Clinical Ageing Research Unit for a single session during which a variety of demographic, clinical (PD groups only), visual and cognitive outcomes will be obtained. We will monitor: (i) regional brain activity using mobile functional near infrared spectroscopy; (ii) visual behaviour using a mobile eye tracker; and (iii) gait mechanics using Vicon high speed cameras. Data will be collected while participants complete the following three walking conditions: unobstructed gait, obstacle crossing and walking with implementation of cues (auditory and visual cues).