Mina Mirahmadi1,2, Mohammad Taghi Karimi3,4, Amir Esrafilian5. 1. Department of Physiotherapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran. 2. Musculoskeletal Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. 3. School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran, mohammad.karimi.bioengineering@gmail.com. 4. Bone and Joint Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran, mohammad.karimi.bioengineering@gmail.com. 5. Eastern Finland University, Kuopio, Finland.
Abstract
BACKGROUND: Postural instability is a common disorder in Parkinson's disease (PD). The aim of this study was to evaluate stance stability of the subjects at the early stage of PD with both linear and nonlinear approaches. Moreover, this study aimed to find the effect of visual control on quiet stance postural control in these patients. METHOD: Seventeen PD patients (Hoehn/Yahr scale: 1) and 17 healthy control subjects were instructed to maintain quiet postural stance in 2 conditions (opened eyes and closed eyes). Four linear (excursion, path length, velocity, root mean square) and 1 nonlinear (approximate entropy) center of pressure (COP) parameters were calculated. A 2 × 2 mixed ANOVA was used for the final analysis. RESULTS: Although there was no difference between the stability of PD patients and healthy control subjects based on excursion of COP in both mediolateral (ML) and anteroposterior (AP) directions, other linear parameters (path length of COP sways, velocity of COP sways, and root mean square in both ML and AP planes) showed that PD patients were significantly unstable compared to normal subjects (p value < 0.05). Vision influenced the stability of both groups significantly. The interaction of vision and group was not significant based on linear and nonlinear stability parameters. CONCLUSION: Although patients in the early stage of PD seem to be unstable based on COP linear measures, their postural control system is still flexible to adapt to environmental perturbations in quiet stance and they are not more visually dependent than healthy subjects to control stability in this position.
BACKGROUND: Postural instability is a common disorder in Parkinson's disease (PD). The aim of this study was to evaluate stance stability of the subjects at the early stage of PD with both linear and nonlinear approaches. Moreover, this study aimed to find the effect of visual control on quiet stance postural control in these patients. METHOD: Seventeen PDpatients (Hoehn/Yahr scale: 1) and 17 healthy control subjects were instructed to maintain quiet postural stance in 2 conditions (opened eyes and closed eyes). Four linear (excursion, path length, velocity, root mean square) and 1 nonlinear (approximate entropy) center of pressure (COP) parameters were calculated. A 2 × 2 mixed ANOVA was used for the final analysis. RESULTS: Although there was no difference between the stability of PDpatients and healthy control subjects based on excursion of COP in both mediolateral (ML) and anteroposterior (AP) directions, other linear parameters (path length of COP sways, velocity of COP sways, and root mean square in both ML and AP planes) showed that PDpatients were significantly unstable compared to normal subjects (p value < 0.05). Vision influenced the stability of both groups significantly. The interaction of vision and group was not significant based on linear and nonlinear stability parameters. CONCLUSION: Although patients in the early stage of PD seem to be unstable based on COP linear measures, their postural control system is still flexible to adapt to environmental perturbations in quiet stance and they are not more visually dependent than healthy subjects to control stability in this position.
Authors: Anna Kamieniarz; Justyna Michalska; Wojciech Marszałek; Magdalena Stania; Kajetan J Słomka; Agnieszka Gorzkowska; Grzegorz Juras; Michael S Okun; Evangelos A Christou Journal: PLoS One Date: 2021-01-12 Impact factor: 3.240