The Latest Articles on Postural Control and Gait in Parkinson’s Disease

Our staff editors continue to share exciting, interesting, and thought-provoking reading material in the recommended articles series.

This week, we would like to share several latest articles on postural control and gait in Parkinson’s disease.

Title: Spatial variability and directional shifts in postural control in Parkinson’s disease
Authors: Damian G. Kelty-Stephen, Ken Kiyono, Nick Stergiou, Madhur Mangalam
Type: Research Article

Abstract:
Individuals with Parkinson’s disease exhibit tremors, rigidity, and bradykinesia, disrupting normal movement variability and resulting in postural instability. This comprehensive study aimed to investigate the link between the temporal structure of postural sway variability and Parkinsonism by analyzing multiple datasets from young and older adults, including individuals with Parkinson’s disease, across various task conditions. We used the Oriented Fractal Scaling Component Analysis (OFSCA), which identifies minimal and maximal long-range correlations within the center of pressure time series, allowing for detecting directional changes in postural sway variability. The objective was to uncover the primary directions along which individuals exerted control during the posture. The results, as anticipated, revealed that healthy adults predominantly exerted control along two orthogonal directions, closely aligned with the anteroposterior (AP) and mediolateral (ML) axes. In stark contrast, older adults and individuals with Parkinson’s disease exhibited control along suborthogonal directions that notably diverged from the AP and ML axes. While older adults and those with Parkinson’s disease demonstrated a similar reduction in the angle between these two control directions compared to healthy older adults, their reliance on this suborthogonal angle concerning endogenous fractal correlations exhibited significant differences from the healthy aging cohort. Importantly, individuals with Parkinson’s disease did not manifest the sensitivity to destabilizing task settings observed in their healthy counterparts, affirming the distinction between Parkinson’s disease and healthy aging.
Access this article: https://doi.org/10.1016/j.prdoa.2024.100249

Title: Unraveling the threads of stability: A review of the neurophysiology of postural control in Parkinson's disease
Authors: Jessica E. Bath, Doris D. Wang
Type: Review

Abstract
Postural instability is a detrimental and often treatment-refractory symptom of Parkinson's disease. While many existing studies quantify the biomechanical deficits among various postural domains (static, anticipatory, and reactive) in this population, less is known regarding the neural network dysfunctions underlying these phenomena. This review will summarize current studies on the cortical and subcortical neural activities during postural responses in healthy subjects and those with Parkinson's disease. We will also review the effects of current therapies, including neuromodulation and feedback-based wearable devices, on postural instability symptoms. With recent advances in implantable devices that allow chronic, ambulatory neural data collection from patients with Parkinson's disease, combined with sensors that can quantify biomechanical measurements of postural responses, future work using these devices will enable better understanding of the neural mechanisms of postural control. Bridging this knowledge gap will be the critical first step towards developing novel neuromodulatory interventions to enhance the treatment of postural instability in Parkinson's disease.
Access this article: https://doi.org/10.1016/j.neurot.2024.e00354

Title: Predicting slight freezing of gait in Parkinson's disease with anticipatory postural adjustments and limits of stability
Authors: Weijia Hou, Fan Wu, Yue Wang, Weihua Li, Yuanyuan Cheng, Zhizhong Zhu, Siquan Liang, Peipei Liu, Yang Yu, Jialing Wu
Type: Research Article

Abstract:

Introduction
Gait initiation (GI) includes automatic and voluntary movements. However, research on their impact on the first step in patients with Parkinson's disease (PD) and their relationship to freezing of gait (FOG) is lacking. We examined the effects of automatic movements (anticipatory postural adjustments [APAs]) and voluntary movements (limits of stability [LOS]) on the first step (first-step duration and first-step range of motion), along with their early recognition and prediction of slight FOG.
Methods
Twenty-three patients with PD and slight freezing (PD + FOG) and 25 non-freezing patients with PD (PD-FOG) were tested while off medications and compared with 24 healthy controls (HC). All participants completed a 7-m Stand and Walk Test (7 m SAW) and wore inertial sensors to quantify the APAs and first step. LOS was quantified by dynamic posturography in different directions using a pressure platform. We compared differences among all three groups, analysed correlations, and evaluated their predictive value for slight FOG.
Results
In PD + FOG, APAs and LOS were worse than those in the PD-FOG and HC groups (p < 0.001), and the first step was worse than that in HC (p < 0.001). APAs were correlated mainly with the first-step duration. APAs and LOS were correlated with the first-step range of motion. APAs have been recognized as independent predictors of FOG, and their combination with LOS enhances predictive sensitivity.      
Conclusion
APAs and LOS in patients with PD directly affect the first step during GI. In addition, the combination of APAs and LOS helped predict slight FOG.
Access this article: https://doi.org/10.1016/j.parkreldis.2024.106949

Title: Reorganization of structural brain networks in Parkinson’s disease with postural instability/gait difficulty
Authors: Zihan Li, Jun Liu, Xinxin Miao, Shaoyun Ge, Jun Shen, Shaohua Jin, Zhengxue Gu, Yongfeng Jia, Kezhong Zhang, Jianwei Wang, Min Wang
Type: Research Article

Abstract:
The Postural Instability/Gait Difficulty (PIGD) subtype of Parkinson’s disease (PD) has a faster disease progression, a higher risk of cognitive and motor decline, yet the alterations of structural topological organization remain unknown.
Diffusion Tensor Imaging (DTI) and 3D-TI scanning were conducted on 31 PD patients with PIGD (PD-PIGD), 30 PD patients without PIGD (PD-non-PIGD) and 35 Healthy Controls (HCs). Structural networks were constructed using DTI brain white matter fiber tractography. A graph theory approach was applied to characterize the topological properties of complex structural networks, and the relationships between significantly different network metrics and motor deficits were analyzed within the PD-PIGD group.
PD-PIGD patients exhibited increased shortest path length compared with PD-non-PIGD and HCs (P < 0.05, respectively). Additionally, PD-PIGD patients exhibited decreased nodal properties, mainly in the cerebellar vermis, prefrontal cortex, paracentral lobule, and visual regions. Notably, the degree centrality of the cerebellar vermis was negatively correlated with the PIGD score (r = −0.390; P = 0.030) and Unified Parkinson’s Disease Rating Scale Part III score (r = −0.436; P = 0.014) in PD-PIGD patients. Furthermore, network-based statistical analysis revealed decreased structural connectivity between the prefrontal lobe, putamen, supplementary motor area, insula, and cingulate gyrus in PD-PIGD patients.
Our findings demonstrated that PD-PIGD patients existed abnormal structural connectomes in the cerebellar vermis, frontal-parietal cortex and visual regions. These topological differences can provide a topological perspective for understanding the potential pathophysiological mechanisms of PIGD in PD.
Access this article: https://doi.org/10.1016/j.neulet.2024.137736

Title: What are the effects of aquatic physiotherapy exercises on speed and complex gait-related activities in individuals with Parkinson's disease?
Authors: Taina Christinelli, Dielise Debona Iucksch, Juliana Siega, Adriano Zanardi da Silva, Vera Lúcia Israel
Type: Research Article

Abstract:
Parkinson's disease (PD) is a central nervous system disease that results in deficits in motor activities such as walking. Gait speed and step length are frequently reduced. Aquatic physiotherapy serves as a form of complementary treatment to promote improvements in the disease's motor symptoms. The purpose of this study was to examine the effect of an aquatic physiotherapy training program on gait in individuals with PD. This is an interventional clinical study in which a group of participants with PD participated in an assessment on the ground of their usual and maximum gait speed using the 10-m Walk Test and complex activities related to gait using the Dynamic Gait Index (DGI) at baseline and 12 weeks of an aquatic physiotherapy intervention, twice a week for 50 min. For statistical analysis, the paired t-test and the Wilcoxon test were used. The study included 10 individuals with PD, in the intermediate stage of PD - H&Y 2 (60%) and 3 (40%), of both sexes with a mean age of 65.8 ± 13.69 years. There was a significant increase in usual gait speed (p = 0.001) and in the DGI score (p = 0.05), but there was no improvement in maximum gait speed (p = 0.119). The aquatic physiotherapy exercise program improved habitual gait speed and the performance of complex activities related to gait in this group individuals with PD.
Access this article: https://doi.org/10.1016/j.jbmt.2024.03.034