The effects of anxiety and external attentional focus on postural control in patients with Parkinson's disease.

Seyede Zohreh Jazaeri,Mohamad Parnianpour,Saeed Behzadipour,Zakieh Sadat Saberi,Seyed Amirhassan Habibi,Ghorban Taghizadeh,Kinda Khalaf,Mahbubeh Mandehgary Najafabadi,Hajar Mehdizadeh,Hawre Rahimzadegan,Akram Azad,Saeed Moradi,John Duda

doi:10.1371/journal.pone.0192168

Abstract

BackgroundAlthough anxiety is a common non-motor outcome of Parkinson's disease (PD) affecting 40% of patients, little attention has been paid so far to its effects on balance impairment and postural control. Improvement of postural control through focusing on the environment (i.e. external focus) has been reported, but the role of anxiety, as a confounding variable, remains unclear.ObjectivesThis study aimed to investigate the influence of anxiety and attentional focus instruction on the standing postural control of PD patients.MethodsThirty-four patients with PD (17 with high anxiety (HA-PD) and 17 with low anxiety (LA-PD)), as well as 17 gender- and age-matched healthy control subjects (HC) participated in the study. Postural control was evaluated using a combination of two levels of postural difficulty (standing on a rigid force plate surface with open eyes (RO) and standing on a foam surface with open eyes (FO)), as well as three attentional focus instructions (internal, external and no focus).ResultsOnly the HA-PD group demonstrated significant postural control impairment as compared to the control, as indicated by significantly greater postural sway measures. Moreover, external focus significantly reduced postural sway in all participants especially during the FO condition.ConclusionThe results of the current study provide evidence that anxiety influences balance control and postural stability in patients with PD, particularly those with high levels of anxiety. The results also confirmed that external focus is a potential strategy that significantly improves the postural control of these patients. Further investigation of clinical applicability is warranted towards developing effective therapeutic and rehabilitative treatment plans.

Highlights

Impaired postural control is a common symptom in patients with Parkinson’s disease (PD), where the severity is known to increase along with the disease progression, predisposing the patients to balance problems, unexpected falls, and various types of injuries [1, 2]
This study aimed to investigate the influence of anxiety and attentional focus instruction on the standing postural control of PD patients
The results confirmed that external focus is a potential strategy that significantly improves the postural control of these patients

Summary

Introduction

Impaired postural control is a common symptom in patients with Parkinson’s disease (PD), where the severity is known to increase along with the disease progression, predisposing the patients to balance problems, unexpected falls, and various types of injuries [1, 2]. Recent functional magnetic resonance imaging (fMRI) studies of PD patients confirm that impaired dopaminergic input to the amygdala and limbic system are associated with emotional abnormalities [10]. These studies demonstrate the neural links between the regions in the brain controlling emotions and those responsible for balance control. Anxiety is a common non-motor outcome of Parkinson’s disease (PD) affecting 40% of patients, little attention has been paid so far to its effects on balance impairment and postural control. Improvement of postural control through focusing on the environment (i.e. external focus) has been reported, but the role of anxiety, as a confounding variable, remains unclear

Objectives

Methods

Conclusion