Relationships between gait and dynamic balance in early Parkinson's disease

Differentiation in theta and gamma activation in weight-shifting learning between people with parkinson's disease of different anxiety severities

Anxiety and postural control deficits may be related in people with Parkinson's disease (PwPD). However, the association between anxiety levels and weight-shifting control remains ambiguous. This study investigated whether 1) weight-shifting control differed between PwPD with and without anxiety, and 2) the learning effect of weight-shifting differed between the two populations. Additionally, we evaluated cortical activities to investigate neural mechanisms underlying weight-shifting control. Twenty-eight PwPD (14 anxiety, 14 nonanxiety) participated in a 5-day weight-shifting study by coupling the bearing weight of their more-affected leg to a sinusoidal target at 0.25 Hz. We tested the weight-shifting control on day 1 (pretest), day 3 (posttest), and day 5 (retention test) with a learning session on day 3. The error and jerk of weight-shifting trajectory and the theta and gamma powers of electroencephalography in prefrontal, frontal, sensorimotor and parietal-occipital areas were measured. At the pretest, the anxiety group showed larger error and smaller jerk of weight-shifting with greater prefrontal theta, frontal gamma, and sensorimotor gamma powers than the nonanxiety group. Anxiety intensity was correlated positively with weight-shifting error and theta power but negatively with weight-shifting jerk. Reduced weight-shifting error with increased theta power after weight-shifting learning was observed in the nonanxiety group. However, the anxiety group showed decreased gamma power after weight-shifting learning without behavior change. Our findings suggest differential weight-shifting control and associated cortical activation between PwPD with and without anxiety. In addition, anxiety would deteriorate weight-shifting control and hinder weight-shifting learning benefits in PwPD, leading to less weight-shifting accuracy and correction.

Visual feedback improves propulsive force generation during treadmill walking in people with Parkinson disease

Persons with Parkinson's disease experience gait alterations, such as reduced step length. Gait dysfunction is a significant research priority as the current treatments targeting gait impairment are limited. This study aimed to investigate the effects of visual biofeedback on propulsive force during treadmill walking in persons with Parkinson's. Sixteen ambulatory persons with Parkinson's participated in the study. They received real-time biofeedback of anterior ground reaction force during treadmill walking at a constant speed. Peak propulsive force values were measured and normalized to body weight. Spatiotemporal parameters were also assessed, including stride length and double support percent. Persons with Parkinson's significantly increased peak propulsive force during biofeedback compared to baseline (p <.0001, Cohen's dz = 1.69). Variability in peak anterior ground reaction force decreased across repeated trials (p <.0001, dz = 1.51). While spatiotemporal parameters did not show significant changes individually, stride length and double support percent improved marginally during biofeedback trials. Persons with Parkinson's can increase propulsive force with visual biofeedback, suggesting the presence of a propulsive reserve. Though stride length did not significantly change, clinically meaningful improvements were observed. Targeting push-off force through visual biofeedback may offer a potential rehabilitation technique to enhance gait performance in Persons with Parkinson's. Future studies could explore the long-term efficacy of this intervention and investigate additional strategies to improve gait in Parkinson's disease.

Exploring Potential Predictors of Treadmill Training Effects in People With Parkinson Disease

OBJECTIVE

To explore the potential predictors of people with Parkinson disease (PD) who would benefit the most from treadmill training.

DESIGN

A cohort study.

SETTING

Medical university rehabilitation settings.

PARTICIPANTS

Seventy participants diagnosed of idiopathic PD.

INTERVENTIONS

Twelve sessions of treadmill training.

MAIN OUTCOME MEASURES

Hierarchical logistic regression models were used to explore significant predictors of the treadmill training effect with respect to 3 health domains: Unified Parkinson's Disease Rating Scales part III (UPDRS III); gait speed; Parkinson's Disease Questionnaire-39 (PDQ-39). A receiver operating characteristic (ROC) curve analysis was conducted to identify proper cut-off points for clinical use.

RESULTS

Male sex (adjusted odds ratio [OR]: 3.73, P=.036) significantly predicted the improvement of UPDRS III. Individuals with a slower baseline gait speed (cut-off: 0.92 m/s, adjusted OR: 14.06, P<.001) and higher baseline balance confidence measured by the Activity-specific Balance Confidence scale (cut-off: 84.5 points, adjusted OR: 4.66, P=.022) have greater potential to achieve clinically relevant improvements in gait speed. A poorer baseline PDQ-39 score (cut-off: 23.1, adjusted OR: 7.47, P<.001) predicted a greater quality of life improvement after treadmill training.

CONCLUSIONS

These findings provide a guideline for clinicians to easily identify suitable candidates for treadmill training. Generalization to more advanced patients with PD warrants further investigation.

Association of activities of daily living, mobility and balance ability, and symptoms of Parkinson's disease with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with Parkinson's disease

PURPOSE

We examined the association of activities of daily living (ADL), mobility and balance ability, and symptoms of Parkinson's disease (PD) with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with PD.

METHODS

The subjects were 11 community-dwelling patients with PD. ADL were assessed using the Functional Independence Measure. Mobility capacity was assessed based on measurement of maximal walking speed and timed up-and-go time, while balance ability was evaluated based on measurement of one-legged stance time. The symptoms of PD were assessed based on measurement of the Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale. Muscle thickness (MT) and echo intensity (EI) of the trunk and lower extremity muscles were also measured using an ultrasound imaging device.

RESULTS

Partial correlation analysis revealed an association between reduced ADL and increased EI of the lumbar erector spinae muscle; reduced mobility capacity and increased EI of the rectus abdominis and gluteus minimus muscles; and reduced balance ability and decreased MT of the lumbar erector spinae muscle and increased EI of the lumbar erector spinae, semitendinosus, and tibialis posterior muscles. Partial correlation analysis also showed an association between symptoms of severe PD and decreased MT of the tibialis anterior muscles and increased EI of the lumbar erector spinae, gluteus minimus, and tibialis posterior muscles.

CONCLUSION

The properties of the trunk and lower extremity muscles may be critical for ADL, mobility and balance ability, and symptoms of PD in patients with PD.

Wearable sensor-based gait analysis to discriminate early Parkinson's disease from essential tremor

BACKGROUND

Differentiating early-stage Parkinson's disease (PD) from essential tremor (ET) is challenging since they have some overlapping clinical features. Since early-stage PD may present with slight gait impairment and ET generally does not, gait analysis could be used to differentiate PD from ET using machine learning.

OBJECTIVE

To differentiate early-stage PD from ET via machine learning using gait and postural transition parameters calculated using the raw kinematic signal captured from inertial measurement unit (IMU) sensors.

METHODS

Gait and postural transition parameters were collected from 84 early-stage PD and 80 ET subjects during the Time Up and Go (TUG) test. We randomly split our data into training and test data. Within the training data, we separated the TUG test into four components: standing, straight walk, turning, and sitting to build weighted average ensemble classification models. The four components' weight indices were trained using logistic regression. Several ensemble models' leave-one-out cross-validation (LOOCV) performances were compared. Independent test data were used to evaluate the model with the best LOOCV performance.

RESULTS

The best weighted average ensemble classification model LOOCV results included an accuracy of 84%, Kappa of 0.68, sensitivity of 85.9%, specificity of 82.1%, and AUC of 0.912. Thirty-three gait and postural transition parameters, such as Arm-Symbolic Symmetry Index and 180° Turn-Max Angular Velocity, were included in Feature Group III. The independent test data achieved a 75.8% accuracy.

CONCLUSIONS

Our findings suggest that gait and postural transition parameters obtained from wearable sensors combined with machine learning had the potential to distinguish between early-stage PD and ET.

A spinal synergy of excitatory and inhibitory neurons coordinates ipsilateral body movements

Innate and goal-directed movements require a high-degree of trunk and appendicular muscle coordination to preserve body stability while ensuring the correct execution of the motor action. The spinal neural circuits underlying motor execution and postural stability are finely modulated by propriospinal, sensory and descending feedback, yet how distinct spinal neuron populations cooperate to control body stability and limb coordination remains unclear. Here, we identified a spinal microcircuit composed of V2 lineage-derived excitatory (V2a) and inhibitory (V2b) neurons that together coordinate ipsilateral body movements during locomotion. Inactivation of the entire V2 neuron lineage does not impair intralimb coordination but destabilizes body balance and ipsilateral limb coupling, causing mice to adopt a compensatory festinating gait and be unable to execute skilled locomotor tasks. Taken together our data suggest that during locomotion the excitatory V2a and inhibitory V2b neurons act antagonistically to control intralimb coordination, and synergistically to coordinate forelimb and hindlimb movements. Thus, we suggest a new circuit architecture, by which neurons with distinct neurotransmitter identities employ a dual-mode of operation, exerting either synergistic or opposing functions to control different facets of the same motor behavior.

The Relationship between Restrictions on Going Out and Motor Imagery among Medical University Students in Japan—Research with Small Samples

Motor imagery is often used as a training method to improve physical performance. Previous studies have often reported that reduced motor imagery is more likely to occur in older adults and stroke patients. However, it has also been reported that it is difficult to imagine exercises that cannot be performed. Therefore, we hypothesized that this may also have occurred in young people who were physically able to exercise but who were restricted by COVID-19 lockdowns, however, we could find no studies that investigated the impact of restricting outings. In this study, 83 healthy young people were measured for physical performance (maximum walking speed, grasp strength, Timed Up and Go test, imagined Timed Up and Go test, functional reach test, and five chair stand test). It was found that, while restricting outings did not influence physical performance in the subjects, it did influence motor imagery. Therefore, it should be borne in mind that training with motor imagery may not generate adequate actual motor imagery when restrictions are imposed on activities.

The predictive relationships between advanced dynamic balance and physical activity/quality of life in Parkinson's disease

Gait and balance problems commonly occur in Parkinson's disease (PD). However, balance tasks with only one performance objective (e.g., sit-to-stand) may not be sufficient, compared to dual motor tasks (e.g., carrying a tray while walking), to be applied to the assessments and interventions which are designed to promote PD patients' balance functioning, physical activity (PA) and health-related quality of life (HQoL). The aim of this study, therefore, was to determine whether advanced dynamic balance, measured by a demanding motor-motor dual task, is a significant predictor of PA/HQoL in older adults with and without PD. Participants with (n = 22) and without (n = 23) PD were assessed using the Berg Balance Scale (BBS), the single leg hop and stick series task (SLHS), the Physical Activity Scale for the Elderly (PASE), and the Parkinson's Disease Questionnaire-39 (PDQ39). We calculated the R² change, namely the incremental validity, between the multiple regression models before and after adding the scores on the BBS/SLHS. While controlling for biological and socioeconomic covariates, competence in the SLHS task provided moderate and large levels of incremental validity to PA (ΔR² = 0.08, Cohen's f² = 0.25, p = .035) and HQoL (ΔR² = 0.13, Cohen's f² = 0.65, p < .001), respectively. In particular for participants with PD, the SLHS explained significantly more variance in HQoL in relation to psychosocial functioning (ΔR² = 0.25, Cohen's f² = 0.42, p = .028) compared to the BBS (p = .296). Assessing advanced dynamic balance by means of a highly demanding dual-task paradigm was not only strongly associated with PA but also covered a wider spectrum of HQoL components. This approach is recommended for use in evaluations and interventions carried out in clinical and research settings in order to promote healthy living.

Evaluation of an Adoptive Cellular Therapy-Based Vaccine in a Transgenic Mouse Model of α-synucleinopathy

Aggregated α-synuclein, a major constituent of Lewy bodies plays a crucial role in the pathogenesis of α-synucleinopathies (SPs) such as Parkinson's disease (PD). PD is affected by the innate and adaptive arms of the immune system, and recently both active and passive immunotherapies targeted against α-synuclein are being trialed as potential novel treatment strategies. Specifically, dendritic cell-based vaccines have shown to be an effective treatment for SPs in animal models. Here, we report on the development of adoptive cellular therapy (ACT) for SP and demonstrate that adoptive transfer of pre-activated T-cells generated from immunized mice can improve survival and behavior, reduce brain microstructural impairment via magnetic resonance imaging (MRI), and decrease α-synuclein pathology burden in a peripherally induced preclinical SP model (M83) when administered prior to disease onset. This study provides preclinical evidence for ACT as a potential immunotherapy for LBD, PD and other related SPs, and future work will provide necessary understanding of the mechanisms of its action.

Motor imagery and action-observation in neurorehabilitation: A study protocol in Parkinson's disease patients

Introduction

Action Observation Treatment (AOT) and Motor Imagery (MI) represent very promising cognitive strategies in neuro-rehabilitation. This study aims to compare the effectiveness of the two cognitive strategies, taken alone or combined, in Parkinson's disease patients.

Material and methods

This study is designed as a prospective randomized controlled trial, with four arms. We estimated a sample size of 64 patients (16 in each treatment group) to be able to detect an effect size of F = 0.4 with a statistical significance of 0.05. Primary outcomes will be functional gains in the FIM and UPDRS scales. Secondary outcome measure will be functional gain as revealed by kinematic parameters measured at Gait Analysis.

Discussion

The results of this trial will provide insights into the use of AOT and MI, taken alone or combined, in the rehabilitation of Parkinson's disease patients.

Ethics and dissemination

The study protocol was approved by the Ethics Committee of the Don Gnocchi Foundation. The study will be conducted in accordance with the 1996 World Medical Association guidelines and according to good clinical practice. The study has been registered on clinicaltrial.gov under the following code: AOTPRFDG. Dissemination will include both submission of the study to peer-reviewed journals and discussion of the study protocol at conferences.

The association between physical performance and subjective wellbeing in Chinese older adults: A cross-sectional study

Purpose

This study aimed to investigate the association between physical performance and subjective wellbeing among Chinese older adults.

Methods

Data on the Chinese population were gathered from the Study on Global Aging and Adult Health Survey (SAGE). This survey used a stratified multistage cluster sample design based on geographical location and economic status. Chinese older adults aged 65 years old or above from eight provinces (Guangdong, Hubei, Jilin, Shaanxi, Shandong, Shanghai, Yunnan, and Zhejiang) were included in this cross-sectional study. Physical performance was measured using relative handgrip strength and normal gait speed. Subjective wellbeing was measured using quality-of-life (QOL), happiness, and mood through interviews with participants. Logistic regressions were used to examine the associations between physical performance and each of the three wellbeing variables (QOL, happiness, and mood).

Results

Data of 5,421 Chinese older adults (mean age: 72.93 ± 5.89 years old, 47.1% men) were analyzed. In this sample, individuals with a higher level of relative handgrip strength (rHGS) had better mood compared to those with a lower level of rHGS (p < 0.05), and persons with lower gait speed had poorer QOL, happiness, and mood compared to those with faster gait speed (p < 0.05).

Conclusion

Our findings suggest that a higher level of relative handgrip strength predicted better mood and lower gait speed predicted poor QOL, happiness, and mood in Chinese older adults.

Gait alterations in Parkinson’s disease at the stage of hemiparkinsonism—A longitudinal study

Background

Progressive gait impairment in Parkinson’s disease (PD) leads to significant disability. Quantitative gait parameters analysis provides valuable information about fine gait alterations.

Objectives

To analyse change of gait parameters in patients with early PD at the stage of hemiparkinsonism and after 1 year of follow up, taking into account clinical asymmetry.

Methods

Consecutive early PD outpatients with strictly unilateral motor features underwent clinical and neuropsychological assessment at the study entry and after 1 year of follow up. Gait was assessed with GAITRite walkway using dual-task methodology. Spatiotemporal gait parameters (step time and length, swing time and double support time) and their coefficients of variation (CV), gait velocity and heel-to-heel base support were evaluated.

Results

We included 42 PD patients with disease duration of 1.3 years (±1.13). Progression of motor and non-motor symptoms, without significant cognitive worsening, was observed after 1 year of follow up. Significant shortening of the swing time, prolongation of the double support and increase of their CVs were observed during all task conditions similarly for most parameters on symptomatic and asymptomatic bodysides, except for CV for the swing time under the combined task.

Conclusion

Alterations of the swing time and double support time are already present even at the asymptomatic body side, and progress similarly, or even at faster pace, at this side, despite dopaminergic treatment These parameters deserve further investigation in larger, prospective studies to address their potential to serve as markers of progression in interventional disease modifying trials with early PD patients.

Gait and posture are correlated domains in Parkinson's disease

Establishing a relationship between gait and posture in patients with Parkinson's disease (PD) is essential for PD treatment and rehabilitation. While previous studies have indicated that gait and posture are independent domains in PD, shared neuromechanisms related to gait and posture control and previous studies investigating the relationship between gait and posture parameters in stroke survivors and neurologically healthy older adults have shown a correlated domain. Thus, this study analyzed the relationship of gait and posture domains, primarily through gait temporal sub-phases (i.e., double support and stance phases) and step width. We analyzed the spatial-temporal gait parameters at the self-selected velocity and center of pressure (CoP) during quiet standing of 22 idiopathic PD participants under and without dopaminergic medication conditions. The association between quiet standing and gait variables was assessed through the Spearman test, controlled by age, disease duration, NFoG-Q, and levodopa dosage. In ON medication, CoP area showed a significant correlation with stance phase and total double support; and RMS ML CoP showed a significant correlation with stance phase, total double support, and step width. In OFF medication, CoP area, RMS AP CoP, RMS ML CoP, and ML CoP velocity significantly correlated with stance phase and total double support. By showing the relationship between gait and posture domains in PD, our study adds novel knowledge about the shared gait-posture control, which could collaborate with new approaches during mobility treatment and assessment.

Biomechanical responses of Nordic walking in people with Parkinson's disease

In healthy adults, Nordic walking (NW) is known to increase the external mechanical energy fluctuations, though the external work is unaltered due to an improved pendulum-like recovery in comparison with free walking (FW). We aimed to compare mechanical, pendulum-like, and spatiotemporal parameters of gait at different speeds with and without NW poles in people with Parkinson's disease and healthy controls. The study included 11 people (aged 65.6 ± 7.0 years) with idiopathic Parkinson's disease, scoring between 1 and 1.5 on the Hoehn and Yahr scale (H&Y), and nine healthy controls (aged 70.0 ± 5.6 years). All the people were experienced Nordic walkers. Walking tests were performed at 1.8 km h^-1 and 4.7 km h^-1 , on eight 3D force platforms on a walkway. We found greater pendulum-like energy recovery (p < 0.05) in the Parkinson group during NW than in FW, while external mechanical work remained similar (p > 0.05). People with Parkinson's disease showed a major increase in vertical and forward energy fluctuations using poles than in healthy controls. In addition, the Parkinson group showed increased stride frequency and reduced stride length compared to controls in the NW and FW conditions. Our findings partly justify the lower walking economy in Parkinson's disease due to reduced pendulum-like mechanism at commonly used speeds. NW alters gait mechanics similarly in Parkinson group and healthy control, increasing the total mechanical work. Therefore, NW can be a compelling strategy for rehabilitation because of its potential for improving functional mobility, increasing pendulum-like mechanism in Parkinson's disease.

Differences in predictors for gait speed and gait endurance in Parkinson's disease

INTRODUCTION

Both gait speed and gait endurance directly impact independence and community engagement for individuals with Parkinson's disease (PD). However, factors accounting for variability in gait speed and gait endurance performance are unclear. The purpose of this study was to investigate whether key factors associated with gait speed in individuals with PD also predicted gait endurance.

METHODS

Community dwelling ambulatory individuals with PD were recruited for a single session. Key measures included 10 Meter Walk Test (10MWT) and 6 Minute Walk Test (6MWT) and key factors: age, disease severity [Movement Disorders Society United Parkinson's Disease Rating Scale (motor scale only) (MDS-UPDRS motor)], plantar flexor strength [Calf Raise Senior (CRS)], fatigue [Fatigue Severity Scale (FSS)], cognition [Montreal Cognitive Assessment (MoCA)], and balance [Four Square Step Test (FSST)]. Multiple linear regression analyses were conducted to determine clinical relationships.

RESULTS

Seventy-two individuals with PD (mean (standard deviation) (age = 70.83 (7.91) years; 50 males; MDS-UPDRS motor = 30.67 (13.50)) completed all assessments. The model predicting gait speed was significant, F(6, 65) = 15.143, p <.001, accounting for 54 % of the variance. Of the predictor variables age, MDS-UPDRS motor, CRS, MoCA and FSST scores were significant predictors. The model predicting gait endurance was significant, F(6, 65) = 15.608, p <.001, accounting for 55 % of the variance. Of the predictor variables, age, MDS-UPDRS motor scale, and CRS scores were significant predictors.

DISCUSSION

Gait speed and gait endurance are similarly influenced by age, motor impairment, and plantarflexion strength. However, cognition and balance were predictors only of gait speed, which may suggest unique task differences exist between gait speed and gait endurance.

Influence of Multiple Sclerosis on Spatiotemporal Gait Parameters: A Systematic Review and Meta-Regression

OBJECTIVE

To quantify the effect of multiple sclerosis (MS) on spatiotemporal gait characteristics accounting for disability severity and fall classification.

DATA SOURCES

MEDLINE (1946-August 2018), Allied and Complementary Medicine Database (1985-2018 August), and PsycINFO (1806-August 2018) were searched for terms on MS and gait.

STUDY SELECTION

Dual independent screening was conducted to identify observational, cross-sectional studies that compared adults with MS grouped according to Expanded Disability Status Scale (EDSS) level or fall history, reported on spatiotemporal gait characteristics, and were published in English. The search retrieved 5891 results, of which 12 studies satisfied the inclusion criteria.

DATA EXTRACTION

Two authors worked independently to extract and verify data on publication details, study methodology, participant characteristics, gait outcomes, conclusions, and limitations. Risk of bias was assessed using the QualSyst critical appraisal tool. A random-effects meta-regression and meta-analysis were conducted on pooled data.

DATA SYNTHESIS

All studies received quality ratings of very good to excellent and collectively examined 1513 individuals with MS. With every 1-point increase in EDSS, significant changes (P<.05) were observed in gait speed (-0.12 m/s; 95% confidence interval (CI), 0.08-0.15), step length (-0.04 m; 95% CI, 0.03-0.05), step time (+0.04 seconds; 95% CI, 0.02-0.06), step time variability (+0.009 seconds; 95% CI, 0.003-0.016), stride time (+0.08 seconds; 95% CI, 0.03-0.12), cadence (-4.4 steps per minute; 95% CI, 2.3-6.4), stance phase duration (+0.8% gait cycle; 95% CI, 0.1-1.5), and double support time (+3.5% gait cycle; 95% CI, 1.5-5.4). Recent fallers exhibited an 18% (95% CI, 13%-23%) reduction in gait speed compared with nonfallers (P<.001).

CONCLUSIONS

This review provides the most accurate reference values to-date that can be used to assess the effectiveness of MS gait training programs and therapeutic techniques for individuals who differ on disability severity and fall classification. Some gait adaptations could be part of adopting a more cautious gait strategy and should be factored into the design of future interventions.

Gait parameters of Parkinson's disease compared with healthy controls: a systematic review and meta-analysis

We systematically reviewed observational and clinical trials (baseline) studies examining differences in gait parameters between Parkinson’s disease (PD) in on-medication state and healthy control. Four electronic databases were searched (November-2018 and updated in October-2020). Independent researchers identified studies that evaluated gait parameters measured quantitatively during self-selected walking speed. Risk of bias was assessed using an instrument proposed by Downs and Black (1998). Pooled effects were reported as standardized mean differences and 95% confidence intervals using a random-effects model. A total of 72 studies involving 3027 participants (1510 with PD and 1517 health control) met the inclusion criteria. The self-selected walking speed, stride length, swing time and hip excursion were reduced in people with PD compared with healthy control. Additionally, PD subjects presented higher cadence and double support time. Although with a smaller difference for treadmill, walking speed is reduced both on treadmill (.13 m s⁻¹) and on overground (.17 m s⁻¹) in PD. The self-select walking speed, stride length, cadence, double support, swing time and sagittal hip angle were altered in people with PD compared with healthy control. The precise determination of these modifications will be beneficial in determining which intervention elements are most critical in bringing about positive, clinically meaningful changes in individuals with PD (PROSPERO protocol CRD42018113042).

The Interaction between Mobility Status and Exercise Specificity in Older Adults

Many adults older than 60 yr experience mobility limitations. Although physical exercise improves older adults' mobility, differences in baseline mobility produce large variations in individual responses to interventions, and these responses could further vary by the type and dose of exercise. Here, we propose an exercise prescription model for older adults based on their current mobility status.

Dopamine-mediated improvements in dynamic balance control in Parkinson's disease

BACKGROUND

Impaired dynamic balance control increases fall risk and contributes to immobility in individuals with Parkinson's disease (PD). It is unclear whether higher-level neural processes of the central nervous system contribute to impaired balance control.

RESEARCH QUESTION

Are dopamine-mediated neural processes of the higher-level central nervous system important for dynamic balance control in PD?

METHODS

21 individuals with idiopathic PD performed step-threshold assessments before and after self-administered dopaminergic medication. Individuals withstood progressively larger postural perturbations, during which they were explicitly instructed to avoid stepping to recover balance. The perturbation magnitude which elicited stepping responses on four consecutive trials is referred to as the step-threshold. Dynamic balance control was quantified as the minimum margin of stability captured during the largest sub-threshold trial (i.e., the maximum amount of compensated postural instability during the task). We compared dynamic balance between off and on medication states and between individuals who exhibited motor adaptive behavior and those who did not.

RESULTS

Dopaminergic medications significantly improved step-thresholds and allowed individuals to withstand greater amounts of instability without stepping, indicating dopamine-mediated improvement in dynamic balance control. Individuals who displayed behavioral evidence for higher-level neural processes (motor adaptation across repeated perturbations) displayed superior dynamic balance control versus those who did not. Anteroposterior ground reaction forces captured during perturbations suggest that individuals alter force profiles to avoid stepping at ∼200 ms after perturbation onset-a latency consistent with a transcortical process.

SIGNIFICANCE

Combined, our results indicate that higher-level, dopamine-mediated neural processes are responsible for dynamic balance control in PD. We hypothesize that this process incorporates sensorimotor integration, motor response initiation/inhibition, and goal- and reward-driven behaviors. Interventions targeting these processes may improve dynamic postural control in individuals with PD.

Characterization of idiopathic Parkinson's disease subgroups using quantitative gait analysis and corresponding subregional striatal uptake visualized using 18F-FP-CIT positron emission tomography

BACKGROUND

Gait disturbance is one of the most common symptoms among patients with idiopathic Parkinson's disease (IPD). Nevertheless, Parkinson's disease subtype clustering according to gait characteristics has not been thoroughly investigated.

RESEARCH QUESTION

The aim of this study was to identify subgroups according to gait pattern among patients with IPD.

METHODS

This study included 88 patients with IPD who underwent ¹⁸F-fluorinated-N-3-fluoropropyl-2-β-carboxymethoxy-3-β-4-iodophenyl-nortropane positron emission tomography (¹⁸F-FP-CIT PET) and three-dimensional gait analysis (3DGA) between January 1, 2014 and December 31, 2016. We performed cluster analysis using temporal-spatial gait variables (gait speed, stride length, cadence, and step width) and divided patients into four subgroups. The kinematic and kinetic gait variables in 3DGA were compared among the four subgroups. Furthermore, we compared the uptake patterns of striatum among the four subgroups using ¹⁸F-FP-CIT PET.

RESULTS

The patients were clustered into subgroups based on gait hypokinesia and cadence compensation. Group 1 had decreased stride length compensating with increased cadence. Group 2 had decreased stride length without cadence compensation and wider step width. Group 3 had relatively spared stride length with decreased cadence. Group 4 had spared stride length and cadence. The uptake of posterior putamen was significantly decreased in Group 3 compared with Group 4.

SIGNIFICANCE

Gait hypokinesia and cadence can help to classify gait patterns in IPD patients. Our subgroups may reflect the different gait patterns in IPD patients.

NEURO-FUZZY SYSTEM FOR DETECTING PD PATIENTS BASED ON EUCLID DISTANCE, FFT, AND PCA

This study proposes a method to distinguish between healthy people and Parkinson’s disease patients using sole pressure sensor data, neural network with weighted fuzzy membership (NEWFM), and preprocessing techniques. The preprocessing techniques include fast Fourier transform (FFT), Euclidean distance, and principal component analysis (PCA), to remove noise in the data for performance enhancement. To make the features usable as inputs for NEWFM, the Euclidean distances between the left and right sole pressure sensor data were used at the first step. In the second step, the frequency scales of the Euclidean distances extracted in the first step were divided into individual scales by the FFT using the Hamming method. In the final step, 1–15 dimensions were extracted as the features of NEWFM from the individual scales by the FFT extracted in the second step by the PCA. An accuracy of 75.90% was acquired from the eight dimensions as the inputs of NEWFM.

Physical activity in patients with Parkinson's disease: A holistic approach based on the ICF model

OBJECTIVES

The International Classification of Functioning, Disability and Health (ICF) is a framework providing information on disability and health. Physical activity's behavior is complex and affected by various factors. We aimed to examine the ICF domains in Parkinson's disease (PD) patients; to compare them in sedentary and non-sedentary PD patients and their association with activity level.

PATIENTS AND METHODS

Sixty PD patients (25 sedentary PD group, 35 non-sedentary PD group) were included in this retrospective study. Functional disability was evaluated using the Movement Disorder Society Unified Parkinson's Disease Rating Scale. The physical activity level was measured by the SenseWear Arm Band activity monitor. Patients' cognitive function, severity of depression and anxiety, the functional impact of fatigue, balance performance (NeuroCom Balance Master System), functional mobility (Timed Up and Go Test, TUG), walking capacity (Six-Minute Walk Test, 6MWT), fear of falling, health-related quality of life are also analyzed.

RESULTS

Sedentary PD patients had worse scores in NeuroCom Balance Master System parameters, TUG score, and 6MWT distance in activities domains of the ICF model as a guide than non-sedentary group (p < 0.05). No statistically significant differences were found in the body structures and function, participation, personal and environmental domains of the ICF model between sedentary and non-sedentary PD groups (p > 0.05). There was no correlation between steps taken per day and NeuroCom Balance Master System parameters, TUG score, and 6MWT distance in both groups (p > 0.05).

CONCLUSION

Patients with sedentary lifestyle had worse scores in postural control/balance, sit-to-stand and walking performance. However, deteriorated dynamic balance may not lead to sedentary lifestyle. Physiotherapy programs should be including the behavior change interventions and motivational strategies to promote activity level in PD.

Gait Analysis in Parkinson's Disease: An Overview of the Most Accurate Markers for Diagnosis and Symptoms Monitoring

The aim of this review is to summarize that most relevant technologies used to evaluate gait features and the associated algorithms that have shown promise to aid diagnosis and symptom monitoring in Parkinson's disease (PD) patients. We searched PubMed for studies published between 1 January 2005, and 30 August 2019 on gait analysis in PD. We selected studies that have either used technologies to distinguish PD patients from healthy subjects or stratified PD patients according to motor status or disease stages. Only those studies that reported at least 80% sensitivity and specificity were included. Gait analysis algorithms used for diagnosis showed a balanced accuracy range of 83.5-100%, sensitivity of 83.3-100% and specificity of 82-100%. For motor status discrimination the gait analysis algorithms showed a balanced accuracy range of 90.8-100%, sensitivity of 92.5-100% and specificity of 88-100%. Despite a large number of studies on the topic of objective gait analysis in PD, only a limited number of studies reported algorithms that were accurate enough deemed to be useful for diagnosis and symptoms monitoring. In addition, none of the reported algorithms and technologies has been validated in large scale, independent studies.

Mechanical Plantar Foot Stimulation in Parkinson's Disease: A Scoping Review

Background: Parkinson′s disease (PD) is the second most prevalent neurodegenerative disease in older individuals. Neurorehabilitation-based interventions such as those improving gait are crucial for a holistic approach and to limit falls. Several studies have recently shown that mechanical plantar foot stimulation is a beneficial intervention for improving gait impairment in PD patients. The objective of this scoping review is to evaluate the beneficial effects of this stimulation on gait parameters, and to analyse protocols of foot stimulation and other effects in non-motor symptoms. Relevant articles were searched in the Medline database using Pubmed and Scopus, using the primary search terms ‘foot stimulation’ OR ‘plantar stimulation’ AND ‘Parkinson’s disease*’. Several protocols have been used for mechanical plantar foot stimulation (ranging from medical devices to textured insoles). The gait parameters that have been shown to be improved are stride length and walking speed. The beneficial effects are achieved after both acute and repeated plantar foot stimulation. Beneficial effects are observed in other organs and systems, such as muscle activation, brain connectivity, cardiovascular control in the central nervous system, and the release of brain-derived neurotrophic factor and cortisol in blood added evidence about this intervention’s impact on brain function. Mechanical plantar foot stimulation is a safe and effective add-on treatment able for improving gait impairments in PD patients during the L-dopa off state. Randomized and controlled clinical trials to study its eventual potentiating effect with different pharmacotherapy regimens are warranted.

ReadySteady intervention to promote physical activity in older adults with Parkinson's disease: Study design and methods

The main motor impairments of gait and balance experienced by people with Parkinson's disease (PD) contribute to a sedentary lifestyle, resulting in poor physical conditioning, loss of functional independence, and reduced quality of life. Despite the known benefits of physical activity in PD, the majority of older adults with PD are insufficiently active. Few studies incorporate behavioral change approaches to promoting physical activity in PD. The main goal of this research is to foster community mobility in older adults with PD by promoting physical activity and improving gait patterns using a theory-based behavioral change intervention. The ReadySteady intervention combines wellness motivation theory with polestriding physical activity, which has been shown to be beneficial for people with PD. The intervention will be tested using a randomized controlled design, including inactive older adults diagnosed with PD. Participants will be randomly assigned the 12-week ReadySteady intervention, 12-week polestriding, and education intervention, or 12-week education intervention. Thirty-six older adults with PD will participate in each of the interventions. Level of physical activity, clinical scores, quantitative measures of gait and balance control, and motivational variables for each intervention will be measured at three time points: pre-intervention, post-intervention (12 weeks), and follow-up (24 weeks). If the intervention is beneficial, it may serve as a sustainable addition to current practice in health promotion efforts serving the PD population.

Asymmetric dynamic center-of-pressure in Parkinson's disease

BACKGROUND

Gait disturbance gradually worsens as Parkinson's disease (PD) progresses, which significantly affects the quality of life of PD patients. Treadmill-based gait analysis systems can measure gait parameters including the dynamic center-of-pressure (COP) trajectory during ambulation. In this study, we hypothesized that altered dynamic COP changes are new gait characteristics for PD patients.

METHODS

Dynamic COP parameters and classic spatiotemporal parameters were obtained for each patient using a treadmill-based system at the maximal comfortable treadmill speed (MCTS). We compared dynamic COP parameters between 44 PD patients and 31 controls, correlated these parameters with clinical and spatiotemporal data, and adjusted for age and MCTS to determine whether the parameters were independent from the treadmill speed. We also evaluated characteristics of COP parameters in relation to the more and less affected sides in PD patients.

RESULTS

During treadmill walking the length of the COP trajectory in the stance phase was decreased, an effect that was more prominent on the more affected side in PD patients. COP parameters related to this change were significantly altered in patients when compared to controls. Asymmetry of the COP trajectories compared between both feet was identified as a significant gait characteristic after adjusting for age and MCTS. The overlaid graphical display of dynamic COP trajectory in PD patients showed "distorted butterfly with asymmetric wing" feature.

CONCLUSION

Dynamic COP asymmetry provides a new and intuitive way to analyze gait abnormalities of PD patients. Further studies with prospective designs will substantiate the clinical usefulness of this feature of gait.

Deep Phenotyping of Parkinson's Disease

Phenotype is the set of observable traits of an organism or condition. While advances in genetics, imaging, and molecular biology have improved our understanding of the underlying biology of Parkinson's disease (PD), clinical phenotyping of PD still relies primarily on history and physical examination. These subjective, episodic, categorical assessments are valuable for diagnosis and care but have left gaps in our understanding of the PD phenotype. Sensors can provide objective, continuous, real-world data about the PD clinical phenotype, increase our knowledge of its pathology, enhance evaluation of therapies, and ultimately, improve patient care. In this paper, we explore the concept of deep phenotyping-the comprehensive assessment of a condition using multiple clinical, biological, genetic, imaging, and sensor-based tools-for PD. We discuss the rationale for, outline current approaches to, identify benefits and limitations of, and consider future directions for deep clinical phenotyping.

Falls and Cognitive Training 2 (FaCT2) study protocol: a randomised controlled trial exploring cognitive training to reduce risk of falls in at-risk older adults

BACKGROUND

The primary cause of traumatic injury in older adults is fall. Recent reports suggest that cognitive function contributes significantly to fall risk. Therefore, by targeting cognitive function for intervention, we could potentially reduce the incidence of fall and injury.

PRIMARY OBJECTIVE

To explore the effectiveness of a 16-week cognitive training (CT) intervention to reduce risk and incidence of fall in community-dwelling older adults at risk for fall.

OUTCOMES

Primary outcome is number of falls over a 16-week period (ascertained by fall calendar method). Secondary outcomes include: change fall risk as indicated by improvement in 10 m walk and 90 s balance tests.

DESIGN/METHODS

The design is a two-group randomised controlled trial. Eligible participants are older adults (aged 65-85) residing in the community who are at risk for fall based on physical performance testing. Following completion of 1-week run-in phase, participants are randomly allocated (1:2) to either a group that is assigned to attention control or to the group that receives CT intervention for a total of 16 weeks. Participants are followed for an additional 4 weeks after intervention. Mann-Whitney U test and Student's t-test will be used to examine between-group differences using intention-to-treat analyses.

DISCUSSION

Limited evidence supports the potential of CT to improve cognition and gait, but no published study has evaluated whether such an intervention would reduce incidence of fall. The present trial is designed to provide initial answers to this question. CT may also improve functioning important in other activities (eg, driving), reducing overall risk of injury in elders.

TRIAL REGISTRATION NUMBER

NCT03190460.

Executive Functioning, Muscle Power and Reactive Balance Are Major Contributors to Gait Adaptability in People With Parkinson's Disease

Background and Aim: The ability to adapt gait when negotiating unexpected hazards is crucial to maintain stability and avoid falling. This study investigated cognitive, physical and psychological factors associated with gait adaptability required for obstacle and stepping target negotiation in people with Parkinson’s disease (PD).

Methods: Fifty-four people with PD were instructed to either: (a) avoid an obstacle at usual step distance; or (b) step onto a target at either a short or long step distance projected on a walkway two heel strikes ahead and then continue walking. Participants also completed clinical [Hoehn & Yahr rating scale; Movement Disorders Society version of the Unified Parkinson’s Disease Rating Scale motor section (MDS-UPDRS-III)], cognitive [simple reaction time, Trail Making and Stroop stepping (difference between incongruent and standard Choice Stepping Reaction Time, CSRT) tests], physical [hip abductor muscle power and reactive balance (pull test from the MDS-UPDRS-III)] and psychological (Fall Efficacy Scale–International) assessments.

Results: Discriminant function analysis revealed Stroop stepping test (inhibitory control) performance was the best predictor of stepping errors across the Gait Adaptability Test (GAT) conditions. Poorer executive function [Trail Making Test (TMT)] and reactive balance predicted poorer stepping accuracy in the short target condition; poorer reactive balance predicted increased number of steps taken to approach the obstacle and the long target; and poorer executive function predicted obstacle avoidance. Weaker hip abductor muscle power, poorer reactive balance, slower reaction time, poorer executive function and higher concern about falling were significant predictors of shorter step length while negotiating the obstacle/targets.

Conclusion: Superior executive function, effective reactive balance and good muscle power were associated with successful gait adaptability. Executive function and reactive balance appear particularly important for precise foot placements; and cognitive capacity for step length adjustments for avoiding obstacles. These findings suggest that impaired inhibitory control contributes to stepping errors and may increase fall risk in people with PD. These findings help elucidate mechanisms for why people with PD fall and may facilitate fall risk assessments and fall prevention strategies for this group.

COMPARISON OF SPATIO-TEMPORAL GAIT VARIABLES IN PATIENTS WITH PARKINSON’S DISEASE AND SWEDD

Scans without evidence of dopaminergic deficit (SWEDD) refers to patients with a normal dopamine transporter scan among patients clinically diagnosed with Parkinson’s disease (PD). It is essential to differentiate SWEDD from PD in order to avoid costly and inappropriate treatments. We investigated differences of gait pattern in PD patients and SWEDD patients. Twelve patients with SWEDD and 8 patients with PD participated in the gait test. All participants were instructed to walk along the GaitRite linear walkway at comfortable velocity. As outcome measure, various spatio-temporal gait variables were derived from commercial GaitRite software. Independent sample [Formula: see text]-tests were evaluated to investigate statistical differences between SWEDD patients and PD patients. SWEDD patients walked more quickly with longer step length compared to PD patients ([Formula: see text]). PD patients exhibited a longer stance phase with increased double-limb support period than SWEDD patients ([Formula: see text]). Step time difference of SWEDD patients was smaller than that of PD patients ([Formula: see text]). These findings suggest quantitative gait variables could be helpful for the identification of potential SWEDD patients. Also, understanding of gait strategies of SWEDD patients might be contributed to their effective medications and treatments.

Speed and temporal adaptations during nonmotorized treadmill walking in Parkinson disease and nondisabled individuals

Few studies have explored the potential of gait analysis and training in nonmotorized treadmill (NMT) in Parkinson's disease (PD) patients. We investigated (a) the walking strategy adopted by patients with PD on NMT and (b) how balance may influence spatiotemporal gait parameters. We enrolled 12 patients with PD of modified Hoehn and Yahr stage 2-3 and 13 nondisabled individuals as controls. All participants were evaluated using Tinetti's performance oriented mobility assessment scale, freezing of gait questionnaire, modified falls efficacy scale, and the timed up and go test. They were asked to ambulate with comfortable and maximal speeds on the NMT. The gait parameters acquired on the NMT included walking speed, cadence (CAD), step length, and vertical ground reaction force, which were calculated for intragroup and intergroup comparisons. The PD group took on with higher contribution of CAD and less contribution of step length to increase walking speed as compared with control group. The postural stability is correlated significantly positively to the CAD at the setting of maximal speed in the PD group. Moreover, a significantly lower ratio of vertical ground reaction force/body weight was noted in the PD group during both comfortable and maximal walking speeds compared with the nondisabled controls. Our study outcomes clearly support the perceived benefits of NMT to differentiate spatiotemporal gait parameters between PD and controls. NMT may potentially be useful to evaluate the recovery of physical activities in PD receiving medications and/or rehabilitation.

Comparing Balance Performance on Force Platform Measures in Individuals with Parkinson's Disease and Healthy Adults

INTRODUCTION

Postural instability is a known contributing factor to balance dysfunction and increased fall risk in those with Parkinson's disease (PD). Computerized posturography employing a force platform system provides objective, quantitative assessments of postural control impairments. This study examines balance performance as measured by force platform (FP) tests in persons with PD compared to age-matched healthy adults. Secondarily, we examine if these FP measures provide diagnostic and clinically meaningful information about the underlying balance impairments in the PD population.

METHODS

Participants-42 individuals with PD (Hoehn and Yahr stage = 2.33 ± 0.77) and 55 age-matched healthy adults-were assessed on three standardized balance measures on a computerized force platform system. Between groups, comparisons of FP performance were analyzed using independent t-test. Within the group, comparisons for the PD cohort were analyzed using ANOVA for comparing disease stage and Mann-Whitney U test for PD subtypes.

RESULTS

The PD cohort demonstrated significantly greater postural instability on the sensory organization test (SOT) measures (P=0.013, CI-95% = 1.286 to 10.37) and slower movement velocity on the limits of stability (LOS) test (P=0.001, CI-95% = 0.597 to 1.595) than the healthy cohort, suggesting that these tests were sensitive to detect sensory integration and voluntary postural control deficits in the PD cohort. Within the PD group, the SOT differentiated between H&Y stages 1-3. The motor control test (MCT) detected changes in reactive postural control mainly in later disease stages. All three FP tests distinguished between PD subtypes, with the Posture Gait Instability subtype demonstrating poorer balance performance than Tremor Dominant subtype.

CONCLUSION

These findings suggest FP measures provide clinically meaningful, diagnostic information in the examination of balance impairments in individuals with PD. FP measures may inform clinicians regarding intrinsic balance deficits and guide them in designing targeted balance interventions to reduce fall risk in persons with PD.

Gait bradykinesia and hypometria decrease as arm swing frequency and amplitude increase

People with Parkinson's disease (PD) have decreased arm swing movements during walking, which can be related to PD motor signs and symptoms. In this context, the aim of this study was to determine the effects of an increased arm swing frequency or amplitude on the gait parameters in people with PD and healthy older adults. Seventeen individuals with PD and 19 older people were invited to walk on a 10 m pathway under three experimental conditions: (i) usual walking (no arm swing instructions); (ii) an increased arm swing amplitude; and (iii) an increased arm swing frequency. Both groups had an increased stride speed, vertical center of mass and arm swing accelerations and decreased double support time under the increased arm swing amplitude and frequency conditions. People with PD were able to modulate the gait parameters according to the experimental conditions, but at a smaller magnitude than the older individuals. These results indicate that bradykinesia and hypometria of gait can be positively overcome by increasing the amplitude and frequency of arm swing. Arm movements should be included in gait rehabilitation protocols for PD.

Evaluation of the turning characteristics according to the severity of Parkinson disease during the timed up and go test

BACKGROUND

Patients with Parkinson disease (PD) experience problems such as falls and freezing of gait during walking and turning in daily activities. However, few studies have examined the relationship between simultaneous turning tasks and the severity of PD.

AIM

To investigate turning characteristics in patients with PD using three-dimensional (3D) analysis during the timed up and go (TUG) test.

METHODS

Thirty individuals performed the TUG test under 3D motion analysis: 10 patients with Hoehn and Yahr (H&Y) stages 2.5 and 3.0 PD (group I), 10 patients with H&Y stage 2.0 PD (group II), and 10 healthy older adult controls. Spatiotemporal and kinematic variables were analyzed during the TUG test with a Vicon 3-D motion analysis system.

RESULTS

The walking speed, step length, step length asymmetry index, range of motion of the hip, knee, and shoulder joints, and foot clearance height significantly differed between patients with PD and the controls. The step length and foot clearance height were significantly different between groups I and II.

DISCUSSION

The step length and foot clearance are different between the severity levels of PD, and the TUG test may be useful for identifying turning characteristics in patients with PD.

CONCLUSIONS

Patients with PD exhibited significant differences in all variables of interest compared to the controls. The step length and foot clearance height as well as the TUG test during the turning phase may be helpful for measuring turning in patients with different severity levels of PD.

Factors Leading to Improved Gait Function in Patients with Subacute or Chronic Central Nervous System Impairments Who Receive Functional Training with the Robot Suit Hybrid Assistive Limb

The factors that lead to the improvement of gait function in patients with diseases of the central nervous system (CNS) who use a hybrid assistive limb (HAL) are not yet fully understood. The purpose of the present study was to analyze these factors to determine the prognosis of the patients' gait function. Patients whose CNS disease was within 180 days since onset were designated as the subacute-phase patients, and patients whose disease onset had occurred more than 180 days previously were designated as chronic-phase patients. Fifteen subacute-phase patients and 15 chronic-phase patients were given HAL training. The study analyzed how post-training walking independence in these patients was affected by the following factors: age, disease, lesion area, lower limb function, balance, period until the start of training, number of training sessions, additional rehabilitation, higher-order cognitive dysfunction, HAL model, and the use of a non-weight-bearing walking-aid. In subacute-phase patients, walking independence was related to lower limb function (r_s = 0.35). In chronic-phase patients, there was a statistically significant correlation between post-training walking independence and balance (r_s = 0.78). In addition, in patients with a severe motor dysfunction that was accompanied by inattention and global cognitive dysfunction, little improvement occurred, even with double-leg model training, because they had difficulty wearing the device. The results demonstrated that the factors that improved walking independence post HAL training differed between patients with subacute- and chronic-stage CNS diseases. The findings may serve as valuable information for future HAL training of patients with CNS diseases.

Backward compared to forward over ground gait retraining have additional benefits for gait in individuals with mild to moderate Parkinson's disease: A randomized controlled trial

Over ground gait retraining in the reverse direction has shown to be beneficial for neurological rehabilitation, but has not yet been investigated in Parkinson's disease (PD). Backwards walking (BW) might be a useful training alternative to improve PD gait and possibly reduce fall risk during complex multi-directional daily activities. The primary aim was to compare the effect of an eight-week forward (FWG) and backwards (BWG) gait retraining program on gait parameters in PD individuals. Twenty-nine participants (aged 71.0±8.8years; UPDRS-III 38.1±12.3; H&Y 2.7±0.5) were randomly assigned to either the control (FWG; n=14) or experimental group (BWG; n=15). Baseline measures included disease severity (UPDRS III), global cognition (MoCA) and depression (PHQ-9). Outcome measures were selected gait variables on the 10m-instrumented-walk-test (i10mWT) assessed before and after the interventions. Both groups improved usual gait speed (FWG: p=0.03, d=0.35; BWG: p<0.01, d=0.35) and height-normalized gait speed (FWG: p=0.04, d=0.35; BWG: p<0.01, d=0.57). Additionally, the BWG demonstrated improved cadence (p<0.01, d=0.67) and stride length (SL; p=0.02, d=0.39). Both interventions were effective to improved gait speed sufficiently to independently navigate in the community.

Exercise in an animal model of Parkinson's disease: Motor recovery but not restoration of the nigrostriatal pathway

Many clinical studies have reported on the benefits of exercise therapy in patients with Parkinson's disease (PD). Exercise cannot stop the progression of PD or facilitate the recovery of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) (Bega et al., 2014). To tease apart this paradox, we utilized a progressive MPTP (1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine) mouse model in which we initiated 4weeks of treadmill exercise after the completion of toxin administration (i.e., restoration). We found in our MPTP/exercise (MPTP+EX) group several measures of gait function that recovered compared to the MPTP only group. Although there was a small recovery of tyrosine hydroxylase (TH) positive DA neurons in the SNpc and terminals in the striatum, this increase was not statistically significant. These small changes in TH could not explain the improvement of motor function. The MPTP group had a significant 170% increase in the glycosylated/non-glycosylated dopamine transporter (DAT) and a 200% increase in microglial marker, IBA-1, in the striatum. The MPTP+EX group showed a nearly full recovery of these markers back to the vehicle levels. There was an increase in GLT-1 levels in the striatum due to exercise, with no change in striatal BDNF protein expression. Our data suggest that motor recovery was not prompted by any significant restoration of DA neurons or terminals, but rather the recovery of DAT and dampening the inflammatory response. Although exercise does not promote recovery of nigrostriatal DA, it should be used in conjunction with pharmaceutical methods for controlling PD symptoms.

Balance training in individuals with Parkinson's disease: Therapist-supervised vs. home-based exercise programme

BACKGROUND

Poor locomotion and balance in Parkinson's disease (PD) often diminishes independence. Accordingly, gait is considered one of the most relevant rehabilitation outcomes, and home-based balance exercises might be a viable mode of exercise delivery for individuals with PD. However, research on PD interventions rarely indicate best practices to deliver exercises. Therefore, this study endeavoured to compare the efficacy of a home-based and therapist-supervised balance programme on gait parameters, dynamic balance, balance confidence and motivation in individuals diagnosed with PD.

METHODS

An experimental study design, including a cluster randomized convenience sample, of 40 participants with idiopathic PD (Hoehn and Yahr stage I-III; age: 65.0±7.7years). Participants were divided into a therapist-supervised (n=24) and home-based group (n=16). Groups received either eight weeks of balance training with an exercise therapist or a DVD. Outcome measures include the instrumented Timed-Up-and-Go, Functional Gait Analysis (FGA), Activity-specific Balance confidence (ABC) scale and Intrinsic Motivation Inventory (IMI).

RESULTS

Both groups improved in stride length (p<0.05). Similar FGA improved by 9% and 16% in the therapist-supervised and home-based group, respectively (p<0.01). Only the therapist-supervised group showed improvements in ABC (p=0.051), stride velocity (p=0.0006) and cadence (p=0.046) over the intervention; the latter two were also better compared to home-based (p<0.05). Furthermore the therapist-supervised group were more motivated (p=002).

CONCLUSION

The home-based balance programme was effective in improving some aspects of gait, albeit the programme supervised by an exercise therapist included somewhat more benefits after the intervention i.e. stride velocity and cadence in individuals with mild to moderate PD.

Gait analysis and clinical correlations in early Parkinson's disease

The aim of our study was to identify and quantify spatiotemporal and kinematic gait parameters obtained by 3D gait analysis (GA) in a group of Parkinson's disease (PD) patients compared with healthy subjects in order to investigate whether early PD patients could present an abnormal gait pattern. Forty-four patients affected by early-stage PD compared with a control group were analyzed. All participants were evaluated with 3D GA in the gait laboratory. The greatest significance in temporal parameters was found in cadence (102.46 ± 13.17 steps/min in parkinsonian patients vs 113.84 ± 4.30 steps/min in control subjects), followed by stride duration (1.19 ± 0.18 seconds right limb and 1.19 ± 0.19 seconds left limb in PD patients vs 0.426 ± 0.16 seconds right limb and 0.429 ± 0.23 seconds left limb in normal subjects) and stance duration. Marked differences were also found in the swing phase and in swing duration (p<0.05), while the stance phase was not significantly different in patients compared with healthy subjects. A statistically different velocity in PD patients (0.082 ± 0.29 m/s) vs healthy subjects (1.33 ± 0.06 m/s) was shown by spatial parameter analysis. Step width, stride length and swing velocity were highly significant parameters, as was average velocity. Our study highlighted some distinguishing characteristics of gait in early PD. Ambulation disorders may be present in the early stage of PD and their detection allows for early medical treatment and possible rehabilitation.

Relationship between Gait Parameters and Postural Stability in Early and Late Parkinson's Disease and Visual Feedback-Based Balance Training Effects

BACKGROUND

Gait disorders or postural instability has been done before. However, lack of reviews has addressed the relation between gait and postural stability in Parkinson's disease (PD).

AIM

The aim was to evaluate the relation between gait parameters and postural stability in early and late stages of PD.

MATERIALS AND METHODS

The forty-one idiopathic PD patients were divided into two groups into a group (A) considered as early PD and group (B) considered as late ambulant PD. They were evaluated for postural stability by computerised dynamic posturography (CDP) device and gait analysis using an 8 m-camera Vicon 612 data capturing system set.

RESULTS

There was a statistically significant improvement of composite equilibrium score, the composite latency of motor response, walking speed and cadence after treatment as compared to before training (p < 0.05) in early PD. However, in the late PD, there was a non-significant change of previous parameters after treatment as compared to before training (p > 0.05). There was a significant correlation between UPDRS motor part score, walking speed and composite equilibrium score after training in early PD (p > 0.05).

CONCLUSIONS

Both gait analysis and CDP are important quantitative assessment tools of gait and posture instability.

Fatigue and Muscle Strength Involving Walking Speed in Parkinson's Disease: Insights for Developing Rehabilitation Strategy for PD

Background. Problems with gait in Parkinson's disease (PD) are a challenge in neurorehabilitation, partly because the mechanisms causing the walking disability are unclear. Weakness and fatigue, which may significantly influence gait, are commonly reported by patients with PD. Hence, the aim of this study was to investigate the association between weakness and fatigue and walking ability in patients with PD. Methods. We recruited 25 patients with idiopathic PD and 25 age-matched healthy adults. The maximum voluntary contraction (MVC), twitch force, and voluntary activation levels were measured before and after a knee fatigue exercise. General fatigue, central fatigue, and peripheral fatigue were quantified by exercise-induced changes in MVC, twitch force, and activation level. In addition, subjective fatigue was measured using the Multidimensional Fatigue Inventory (MFI) and Fatigue Severity Scale (FSS). Results. The patients with PD had lower activation levels, more central fatigue, and more subjective fatigue than the healthy controls. There were no significant differences in twitch force or peripheral fatigue index between the two groups. The reduction in walking speed was related to the loss of peripheral strength and PD itself. Conclusion. Fatigue and weakness of central origin were related to PD, while peripheral strength was important for walking ability. The results suggest that rehabilitation programs for PD should focus on improving both central and peripheral components of force.

Imposed Faster and Slower Walking Speeds Influence Gait Stability Differently in Parkinson Fallers

OBJECTIVE

To evaluate the effect of imposed faster and slower walking speeds on postural stability in people with Parkinson disease (PD).

DESIGN

Cross-sectional cohort study.

SETTING

General community.

PARTICIPANTS

Patients with PD (n=84; 51 with a falls history; 33 without) and age-matched controls (n=82) were invited to participate via neurology clinics and preexisting databases. Of those contacted, 99 did not respond (PD=36; controls=63) and 27 were not interested (PD=18; controls=9). After screening, a further 10 patients were excluded; 5 had deep brain stimulation surgery and 5 could not accommodate to the treadmill. The remaining patients (N=30) completed all assessments and were subdivided into PD fallers (n=10), PD nonfallers (n=10), and age-matched controls (n=10) based on falls history.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Three-dimensional accelerometers assessed head and trunk accelerations and allowed calculation of harmonic ratios and root mean square (RMS) accelerations to assess segment control and movement amplitude.

RESULTS

Symptom severity, balance confidence, and medical history were established before participants walked on a treadmill at 70%, 100%, and 130% of their preferred speed. Head and trunk control was lower for PD fallers than PD nonfallers and older adults. Significant interactions indicated head and trunk control increased with speed for PD nonfallers and older adults, but did not improve at faster speeds for PD fallers. Vertical head and trunk accelerations increased with walking speed for PD nonfallers and older adults, while the PD fallers demonstrated greater anteroposterior RMS accelerations compared with both other groups.

CONCLUSIONS

The results suggest that improved gait dynamics do not necessarily represent improved walking stability, and this must be respected when rehabilitating gait in patients with PD.

Reliability and Validity of Force Platform Measures of Balance Impairment in Individuals With Parkinson Disease

BACKGROUND

Complex movement and balance impairments in people with Parkinson disease (PD) contribute to high fall risk. Comprehensive balance assessment is warranted to identify intrinsic fall risk factors and direct interventions.

OBJECTIVE

The purpose of this study was to examine the psychometric properties of 3 balance measures of a force platform (FP) system in people with PD.

METHODS

Forty-two community-dwelling individuals with idiopathic PD completed the testing protocol. Test-retest reliability was assessed for the Limits of Stability Test (LOS), Motor Control Test (MCT), and Sensory Organization Test (SOT). Intraclass correlation coefficients (ICC [2,1]) were calculated to determine test-retest reliability and minimal detectable change. Validity was assessed by comparing the FP measures with criterion gait and balance measures using Pearson product moment correlations. Multiple regression analyses examined the contribution of PD characteristics to FP measures.

RESULTS

All primary FP variables demonstrated excellent test-retest reliability (ICC=.78-.92). The SOT and LOS demonstrated fair to good correlations with criterion measures, whereas the MCT had fair correlations to balance measures only. Both SOT composite equilibrium and MCT average latency were moderately associated with disease severity.

LIMITATIONS

This study's sample had a relatively small number of participants with a positive fall history, which may limit the generalizability of the findings.

CONCLUSIONS

This study's findings provide support that FP measures are reliable and valid tests of balance impairment in people with PD. Disease severity was significantly associated with SOT and MCT measures, perhaps reflecting that these tests are meaningful indicators of decline in postural control with disease progression. Force platform measures may provide valuable quantitative information about underlying balance impairments in people with PD to guide therapeutic interventions for fall risk reduction.

Classification of Parkinson's Disease Gait Using Spatial-Temporal Gait Features

Quantitative gait assessment is important in diagnosis and management of Parkinson's disease (PD); however, gait characteristics of a cohort are dispersed by patient physical properties including age, height, body mass, and gender, as well as walking speed, which may limit capacity to discern some pathological features. The aim of this study was twofold. First, to use a multiple regression normalization strategy that accounts for subject age, height, body mass, gender, and self-selected walking speed to identify differences in spatial-temporal gait features between PD patients and controls; and second, to evaluate the effectiveness of machine learning strategies in classifying PD gait after gait normalization. Spatial-temporal gait data during self-selected walking were obtained from 23 PD patients and 26 aged-matched controls. Data were normalized using standard dimensionless equations and multiple regression normalization. Machine learning strategies were then employed to classify PD gait using the raw gait data, data normalized using dimensionless equations, and data normalized using the multiple regression approach. After normalizing data using the dimensionless equations, only stride length, step length, and double support time were significantly different between PD patients and controls (p < 0.05); however, normalizing data using the multiple regression method revealed significant differences in stride length, cadence, stance time, and double support time. Random Forest resulted in a PD classification accuracy of 92.6% after normalizing gait data using the multiple regression approach, compared to 80.4% (support vector machine) and 86.2% (kernel Fisher discriminant) using raw data and data normalized using dimensionless equations, respectively. Our multiple regression normalization approach will assist in diagnosis and treatment of PD using spatial-temporal gait data.

Pharmacological treatment in Parkinson's disease: Effects on gait

Gait impairments are a hallmark of Parkinson's disease (PD), both as early symptom and an important cause of disability later in the disease course. Although levodopa has been shown to improve gait speed and step length, the effect of dopamine replacement therapy on other aspects of gait is less well understood. In fact, falls are not reduced and some aspects of postural instability during gait are unresponsive to dopaminergic treatment. Moreover, many medications other than dopaminergic agents, can benefit or impair gait in people with PD. We review the effects of pharmacological interventions used in PD on gait, discriminating, whenever possible, among effects on four components of everyday mobility: straight walking, gait initiation, turning, gait adaptability. Additionally, we summarize the effects on freezing of gait. There is substantial evidence for improvement of spatial characteristics of simple, straight-ahead gait with levodopa and levodopa-enhancing drugs. Recent work suggests that drugs aiming to enhance the acetylcholine system might improve gait stability measures. There is a lack of well-designed studies to evaluate effects on more complex, but highly relevant walking abilities such as turning and making flexible adjustments to gait. Finally, paucity in the literature exists on detrimental effects of drugs used in PD that are known to worsen gait and postural stability in the elderly population.

Investigation of factors impacting mobility and gait in Parkinson disease

Mobility and gait limitations are major issues for people with Parkinson disease (PD). Identification of factors that contribute to these impairments may inform treatment and intervention strategies. In this study we investigated factors that predict mobility and gait impairment in PD. Participants with mild to moderate PD and without dementia (n=114) were tested in one session 'off' medication. Mobility measures included the 6-Minute Walk test and Timed-Up-and-Go. Gait velocity was collected in four conditions: forward preferred speed, forward dual task, forward fast as possible and backward walking. The predictors analyzed were age, gender, disease severity, balance, balance confidence, fall history, self-reported physical activity, and executive function. Multiple regression models were used to assess the relationships between predictors and outcomes. The predictors, in different combinations for each outcome measure, explained 55.7% to 66.9% of variability for mobility and 39.5% to 52.8% for gait velocity. Balance was the most relevant factor (explaining up to 54.1% of variance in mobility and up to 45.6% in gait velocity). Balance confidence contributed to a lesser extent (2.0% to 8.2% of variance) in all models. Age explained a small percentage of variance in mobility and gait velocity (up to 2.9%). Executive function explained 3.0% of variance during forward walking only. The strong predictive relationships between balance deficits and mobility and gait impairment suggest targeting balance deficits may be particularly important for improving mobility and gait in people with PD, regardless of an individual's age, disease severity, fall history, or other demographic features.

Gait characteristics, balance performance and falls in ambulant adults with cerebral palsy: An observational study

The relationship between spatiotemporal gait parameters, balance performance and falls history was investigated in ambulant adults with cerebral palsy (CP). Participants completed a single assessment of gait using an instrumented walkway at preferred and fast speeds, balance testing (Balance Evaluation Systems Test; BESTest), and reported falls history. Seventeen ambulatory adults with CP, mean age 37 years, participated. Gait speed was typically slow at both preferred and fast speeds (mean 0.97 and 1.21m/s, respectively), with short stride length and high cadence relative to speed. There was a significant, large positive relationship between preferred gait speed and BESTest total score (ρ=0.573; p<0.05) and fast gait speed and BESTest total score (ρ=0.647, p<0.01). The stride lengths of fallers at both preferred and fast speeds differed significantly from non-fallers (p=0.032 and p=0.025, respectively), with those with a prior history of falls taking shorter strides. Faster gait speed was associated with better performance on tests of anticipatory and postural response components of the BESTest, suggesting potential therapeutic training targets to address either gait speed or balance performance. Future exploration of the implications of slow walking speed and reduced stride length on falls and community engagement, and the potential prognostic value of stride length on identifying falls risk is recommended.