Parkinson's disease‐related changes in the behavioural synergy between eye movements and postural movements. (28th June 2021)

• Record Type: Journal Article
• Authors: Bonnet, Cédrick T.; Delval, Arnaud; Singh, Tarkeshwar; Defebvre, Luc
• Is Part Of: European journal of neuroscience. Volume 54:Number 3(2021)
• Page Start: 5161
• Page End: 5172
• Publication Date: 2021-06-28
• Subjects: automatic vs. higher order behaviours -- eye and postural movements -- Parkinson's disease‐related impairments -- synergic model -- visual performance; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.15351
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Patients with Parkinson's disease (PD patients) have been shown to exhibit abnormally low levels of synergy in their posture control. The goal of this study was to determine how synergic interactions between vision and posture are affected in PD patients. These synergic interactions were expected to be impaired because PD affects the basal ganglia, which are involved in the modulation of both types of movement. Twenty patients (mean age: 60) on levodopa and 20 age‐matched‐controls (mean age: 61) performed a precise visual task (searching for targets in an image) and an unprecise control task (randomly looking at an image) in which images were projected onto a large panoramic display. Lower back, upper back, head and eye movements were recorded simultaneously. To test behavioural synergies, Pearson correlations between eye and postural movements were analysed. The relationships between eye movements and upper and lower back movements were impaired in the patients. The age‐matched controls did not show any significant correlations between eye and postural movements. Overall, our results showed that the PD patients failed to adjust and control their postural stability for success in the visual task. The impaired synergy between eye and postural movements was not related to clinical variables—probably because our patients had early‐stage PD. Our results showed that impairments in synergy can occur very early in PD. Hence, the analysis of this synergy might provide a better understanding of postural instability, visual task performance in the upright stance, and perhaps the risk of falls in PD patients. Abstract : Our results showed that in the precise visual search task, (i) the PD patients showed significant positive linear correlations between eye movement and upper back/lower back movements (discussed as destabilizing relations) and (ii) the age‐matched controls showed no significant relations in all our analyses.