Original Research ARTICLE
A novel MRI compatible balance simulator to detect postural instability in Parkinson's disease
- 1School of Kinesiology, University of British Columbia, Canada
- 2Pacific Parkinson's Research Centre, University of British Columbia, Canada
- 3Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Canada
- 4Department of kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Canada
- 5Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Netherlands
- 6International Collaboration On Repair Discoveries, Vancouver Coastal Health Research Institute, Canada
Background: Postural instability is a debilitating and largely treatment-resistant symptom of Parkinson’s disease (PD). A better understanding of the neural substrates contributing to postural instability could lead to new targets for improved pharmacological and neurosurgical interventions. However, investigating these neural substrates necessitates the use of functional MRI scanners, which are almost exclusively horizontally-based. Objective: We aimed to develop, and validate the use of, an MRI compatible balance simulator to study static and dynamic balance control in PD patients and elderly controls (EC). Methods: Our MRI compatible balance simulator allowed participants to actively balance an inverted pendulum by activating postural muscles around the ankle joint while supine. Two studies were performed to compare static and dynamic balance performance between upright stance and simulated stance in PD patients and controls. Study 1 (14 PD; 20 EC) required participants to maintain static balance during upright and simulated stance for 120 s with eyes open and closed. In study 2 (20 PD; 22 EC) participants repeated the static balance task (80 s, eyes closed only), and also completed a dynamic balance task which required maintaining balance while experiencing random anterior-posterior perturbations applied to the trunk/pendulum. Postural sway of the body/pendulum was measured using an angular velocity sensor (SwayStarTM, study 1) and Optotrak motion capture (study 2). Outcome measures were amplitude and frequency of centre of mass sway for static balance, and peak and time-to-peak of centre of mass displacement and velocity for dynamic balance. Results: PD patients had larger sway amplitude during both upright and simulated static balance compared to controls. PD patients had larger peak and time-to-peak sway, and larger time-to-peak sway velocity, during simulated, but not upright, dynamic balance compared to controls. Conclusions: Deficits in static and dynamic balance control can be detected in PD patients using a novel MRI compatible balance simulator. This technique allows for functional neuroimaging to be combined with balance-relevant tasks, and provides a new means to create insights into the neural substrates contributing to postural instability in PD.
Keywords: Parkinson' disease, postural instability, Elderly, static balance, dynamic balance, balance simulator, centre of mass sway, kinematics
Received: 16 Apr 2019;
Accepted: 09 Aug 2019.
Copyright: © 2019 Pasman, McKeown, Cleworth, Bloem, Inglis and Carpenter. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: PhD. Mark G. Carpenter, School of Kinesiology, University of British Columbia, Vancouver, V6T 1Z1, British Columbia, Canada, email@example.com