The efficacy of quantitative gait analysis by the GAITRite system in evaluation of parkinsonian bradykinesia

Comparison of spatiotemporal gait parameter measurements across various emulated foot strike patterns between the Tekscan® Strideway™ pressure sensitive walkway and gold-standard marker-based motion capture

Spatiotemporal gait parameters are commonly used to quantify physical functioning including in populations with atypical foot strike patterns. The current gold standard measurement system for gait analysis is marker-based motion capture and floor-mounted force plates, but it can be expensive and cumbersome to set up. Pressure sensitive walkways are more affordable, quicker to set up, and more portable. Currently available walkways have not been compared to marker-based motion capture when measuring atypical foot strike patterns. The recently developed Tekscan® Strideway pressure sensitive walkway system has not been compared to any gold standard. This study compared measurements of step width, step length, and step time from the Strideway™ system against a gold standard marker-based motion capture (Vicon® Vantage™) and floor-mounted force plate (AMTI®) system. Ten typically ambulating adults, free of injury, emulated five different foot strike patterns recording two-hundred footsteps for each. Results indicate that the Strideway™ compares well to the gold standard especially under typical foot strike patterns. The errors were highest for step width and near-zero for step time. However, the user needs to be aware that errors can substantially increase with certain foot strike patterns such as when the heel does not make contact with the walkway. The results of this study will help inform users about potential limitations when using a pressure sensitive walkway like the Strideway™ for testing populations with typical and atypical strike patterns.

Noradrenergic cardiac denervation is associated with gait velocity in Parkinson disease: a dual ligand PET study

PURPOSE

Preliminary data suggest that gait abnormalities in Parkinson disease (PD) may be associated with sympathetic cardiac denervation. No kinematic gait studies were performed to confirm this observation. We aimed to correlate spatiotemporal kinematic gait parameters with cardiac sympathetic denervation as determined by cardiac [11C]HED PET in PD.

METHODS

Retrospective database analysis of 27 PD patients with cardiac sympathetic denervation. All patients underwent spatiotemporal kinematic gait assessment (medication 'off' state), cardiac [11C]HED and dopaminergic brain [11C]DTBZ PET scans. We employed a hierarchical regression approach to examine associations between the extent of cardiac denervation, dopaminergic nigrostriatal neurodegeneration, and three gait parameters - velocity, step length and cadence.

RESULTS

More extensive cardiac denervation was associated with slower velocity (estimate: -1.034, 95% CI [-1.65, -0.42], p = 0.002), shorter step length (estimate: -0.818, 95% CI [-1.43, -0.21], p = 0.011) and lower cadence (estimate: -0.752, 95% CI [-1.28, -0.23], p = 0.007) explaining alone 30% (Adjusted-R²: 0.297), 20% (Adjusted-R²: 0.202) and 23% (Adjusted-R²: 0.227) of the variability, respecivetly. These associations remained independent of striatal dopaminergic impairment and confounding factors such as age, Hoehn and Yahr (HY) stages, peripheral neuropathy, cognition, and autonomic symptoms. In contrast, striatal dopaminergic denervation was significantly associated with step length (estimate: 0.883, 95% CI [0.29, 1.48], p = 0.005), explaining about 24% of the variability but was dependent of HY stage.

CONCLUSIONS

More severe cardiac noradrenergic denervation was associated with lower gait velocity, independent of striatal dopaminergic denervation and HY stage, impacting both step length and cadence. These results suggest independent contributions of the peripheral autonomic system degeneration on gait dynsfunction in PD.

Short Step Length Estimation for Parkinson's Disease Patients by Using Fusion Data From Camera-IMU in Smart Glasses

Shortened step length is a prominent motor abnormality in Parkinson's disease (PD) patients. Current methods for estimating short step length have the limitation of relying on laboratory scenarios, wearing multiple sensors, and inaccurate estimation results from a single sensor. In this paper, we proposed a novel method for estimating short step length for PD patients by fusing data from camera and inertial measurement units in smart glasses. A simultaneous localization and mapping technique and acceleration thresholding-based step detection technique were combined to realize the step length estimation. Two sets of experiments were conducted to demonstrate the performance of our method. In the first set of experiments with 12 healthy subjects, the proposed method demonstrated an average error of 8.44% across all experiments including six fixed step lengths below 30 cm. The second set of straightly walking experiments were implemented with 12 PD patients, the proposed method exhibited an average error of 4.27% compared to a standard gait evaluation technique in total walking distance. Notably, among the results of step lengths below 40 cm, our method agreed with the standard technique (R 2=0.8659). This study offers a promising approach for estimating short step length for PD patients during smart glasses-based gait training.

APDM gait and balance measures fail to predict symptom progression rate in Parkinson's disease

Parkinson's disease (PD) results in progressively worsening gait and balance dysfunction that can be measured using computerized devices. We utilized the longitudinal database of the Parkinson's Disease Biomarker Program to determine if baseline gait and balance measures predict future rates of symptom progression. We included 230, 222, 164, and 177 PD subjects with 6, 12, 18, and 24 months of follow-up, respectively, and we defined progression as worsening of the following clinical parameters: MDS-UPDRS total score, Montreal Cognitive Assessment, PDQ-39 mobility subscale, levodopa equivalent daily dose, Schwab and England score, and global composite outcome. We developed ridge regression models to independently estimate how each gait or balance measure, or combination of measures, predicted progression. The accuracy of each ridge regression model was calculated by cross-validation in which 90% of the data were used to estimate the ridge regression model which was then tested on the 10% of data left out. While the models modestly predicted change in outcomes at the 6-month follow-up visit (accuracy in the range of 66–71%) there was no change in the outcome variables during this short follow-up (median change in MDS-UPDRS total score = 0 and change in LEDD = 0). At follow-up periods of 12, 18, and 24 months, the models failed to predict change (accuracy in the held-out sets ranged from 42 to 60%). We conclude that this set of computerized gait and balance measures performed at baseline is unlikely to help predict future disease progression in PD. Research scientists must continue to search for progression predictors to enhance the performance of disease modifying clinical trials.

Accuracy of Step Count Estimations in Parkinson’s Disease Can Be Predicted Using Ambulatory Monitoring

Objectives

There are concerns regarding the accuracy of step count in Parkinson’s disease (PD) when wearable sensors are used. In this study, it was predicted that providing the normal rhythmicity of walking was maintained, the autocorrelation function used to measure step count would provide relatively low errors in step count.

Materials and Methods

A total of 21 normal walkers (10 without PD) and 27 abnormal walkers were videoed while wearing a sensor [Parkinson’s KinetiGraph (PKG)]. Median step count error rates were observed to be <3% in normal walkers but ≥3% in abnormal walkers. The simultaneous accelerometry data and data from a 6-day PKG were examined and revealed that the 5th percentile of the spectral entropy distribution, among 10-s walking epochs (obtained separately), predicted whether subjects had low error rate on step count with reference to the manual step count from the video recording. Subjects with low error rates had lower Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS III) scores and UPDRS III Q10–14 scores than the high error rate counterparts who also had high freezing of gait scores (i.e., freezing of gait questionnaire).

Results

Periods when walking occurred were identified in a 6-day PKG from 190 non-PD subjects aged over 60, and 155 people with PD were examined and the 5th percentile of the spectral entropy distribution, among 10-s walking epochs, was extracted. A total of 84% of controls and 72% of people with PD had low predicted error rates. People with PD with low bradykinesia scores (measured by the PKG) had step counts similar to controls, whereas those with high bradykinesia scores had step counts similar to those with high error rates. On subsequent PKGs, step counts increased when bradykinesia was reduced by treatment and decreased when bradykinesia increased. Among both control and people with PD, low error rates were associated with those who spent considerable time making walks of more than 1-min duration.

Conclusion

Using a measure of the loss of rhythmicity in walking appears to be a useful method for detecting the likelihood of error in step count. Bradykinesia in subjects with low predicted error in their step count is related to overall step count but when the predicted error is high, the step count should be assessed with caution.

Differential diagnosis between Parkinson's disease and atypical parkinsonism based on gait and postural instability: Artificial intelligence using an enhanced weight voting ensemble model

BACKGROUND

Parkinsonian diseases and cerebellar ataxia among movement disorders, are representative diseases which present with distinct pathological gaits. We proposed a machine learning system that can differentiate Parkinson's disease (PD), cerebellar ataxia and progressive supranuclear palsy Richardson syndrome (PSP-RS) based on postural instability and gait analysis.

METHODS

We screened 1467 gait (GAITRite) and postural instability (Pedoscan) analyses performed in Samsung Medical Center from January 2019 to December 2020. PD, probable PSP-RS, and cerebellar ataxia (i.e., probable MSA-C, hereditary ataxia, and sporadic adult-onset ataxia) were included in the study. The gated recurrent units for GaitRite and the deep neural network for Pedoscan were applied. The enhanced weight voting ensemble (EWVE) method was applied to incorporate the two modalities.

RESULTS

We included 551 PD, 38 PSP-RS, 113 cerebellar ataxia and among them, 71 were MSA-C. Pedoscan-based and Gait-based model showed high sensitivity but low specificity in differentiating atypical parkinsonism from PD. The EWVE showed significantly improved specificity and reliable performance in differentiation between PD vs. ataxia patients (AUC 0.974 ± 0.036, sensitivity 0.829 ± 0.217, specificity 0.969 ± 0.038), PD vs. MSA-C (AUC 0.975 ± 0.020, sensitivity 0.823 ± 0.162, specificity 0.932 ± 0.030) and PD vs. PSP-RS (AUC 0.963 ± 0.028, sensitivity 0.555 ± 0.157, specificity 0.936 ± 0.031).

CONCLUSION

We proposed reliable Pedoscan-based, Gait-based and EWVE model in differentiating gait disorders by integrating information from gait and postural instability. This model can provide diagnosis guidelines to primary caregivers and assist in differential diagnosis of PD from atypical parkinsonism for neurologists.

Co-evolution of machine learning and digital technologies to improve monitoring of Parkinson's disease motor symptoms

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor impairments such as tremor, bradykinesia, dyskinesia, and gait abnormalities. Current protocols assess PD symptoms during clinic visits and can be subjective. Patient diaries can help clinicians evaluate at-home symptoms, but can be incomplete or inaccurate. Therefore, researchers have developed in-home automated methods to monitor PD symptoms to enable data-driven PD diagnosis and management. We queried the US National Library of Medicine PubMed database to analyze the progression of the technologies and computational/machine learning methods used to monitor common motor PD symptoms. A sub-set of roughly 12,000 papers was reviewed that best characterized the machine learning and technology timelines that manifested from reviewing the literature. The technology used to monitor PD motor symptoms has advanced significantly in the past five decades. Early monitoring began with in-lab devices such as needle-based EMG, transitioned to in-lab accelerometers/gyroscopes, then to wearable accelerometers/gyroscopes, and finally to phone and mobile & web application-based in-home monitoring. Significant progress has also been made with respect to the use of machine learning algorithms to classify PD patients. Using data from different devices (e.g., video cameras, phone-based accelerometers), researchers have designed neural network and non-neural network-based machine learning algorithms to categorize PD patients across tremor, gait, bradykinesia, and dyskinesia. The five-decade co-evolution of technology and computational techniques used to monitor PD motor symptoms has driven significant progress that is enabling the shift from in-lab/clinic to in-home monitoring of PD symptoms.

Improvised active music therapy for clients with Parkinson’s disease: A feasibility study

The purpose of this study was to test the feasibility of delivering Improvised Active Music Therapy sessions in measuring the impact of acquisition of rhythmic complexity levels on gait performance in individuals with Parkinson’s disease. In this single subject multiple baseline design, the study measured the ability of three right-handed participants with Parkinson’s disease to acquire greater density of syncopation, as a measure of rhythmic complexity levels, while playing uninterrupted improvised music on a simplified electronic drum-set. The music content of the sessions was transformed into digital music data in real-time using Musical Instrument Digital Interface. The Musical Instrument Digital Interface data were analyzed to determine the participants’ and the Music Therapist’s density of syncopation (on acoustic guitar) during baseline and treatment conditions. Results from visual analyses and Pearson’s correlations on the outcomes indicated conflicting and inconclusive outcomes about whether higher acquisition of rhythmic complexity levels improves gait performance in individuals with Parkinson’s disease. Despite this, evidence was found to support the overall value of Improvised Active Music Therapy sessions on gait performance. The study design, the intervention, and outcome measures were found to be feasible and could be scaled-up into a larger trial.

Evaluating the Accuracy of Virtual Reality Trackers for Computing Spatiotemporal Gait Parameters

Ageing, disease, and injuries result in movement defects that affect daily life. Gait analysis is a vital tool for understanding and evaluating these movement dysfunctions. In recent years, the use of virtual reality (VR) to observe motion and offer augmented clinical care has increased. Although VR-based methodologies have shown benefits in improving gait functions, their validity against more traditional methods (e.g., cameras or instrumented walkways) is yet to be established. In this work, we propose a procedure aimed at testing the accuracy and viability of a VIVE Virtual Reality system for gait analysis. Seven young healthy subjects were asked to walk along an instrumented walkway while wearing VR trackers. Heel strike (HS) and toe off (TO) events were assessed using the VIVE system and the instrumented walkway, along with stride length (SL), stride time (ST), stride width (SW), stride velocity (SV), and stance/swing percentage (STC, SWC%). Results from the VR were compared with the instrumented walkway in terms of detection offset for time events and root mean square error (RMSE) for gait features. An absolute offset between VR- and walkway-based data of (15.3 ± 12.8) ms for HS, (17.6 ± 14.8) ms for TOs and an RMSE of 2.6 cm for SW, 2.0 cm for SL, 17.4 ms for ST, 2.2 m/s for SV, and 2.1% for stance and swing percentage were obtained. Our findings show VR-based systems can accurately monitor gait while also offering new perspectives for VR augmented analysis.

Gait Disturbance Improvement and Cerebral Cortex Rearrangement by Acupuncture in Parkinson's Disease: A Pilot Assessor-Blinded, Randomized, Controlled, Parallel-Group Trial

BACKGROUND

Parkinson's disease (PD) leads to impaired mobility and limited independence.

OBJECTIVE

We investigated the effects of acupuncture on gait disturbance and analyzed hemodynamic changes caused by acupuncture in the cerebral cortex of patients with PD.

METHODS

Participants (n = 26) with gait disturbance due to PD were randomly assigned to the intervention (acupuncture twice a week for 4 weeks + conventional therapy) or control (conventional therapy) groups. We analyzed gait parameters using the GAITRite system and hemodynamic responses in the cerebral cortices using functional near-infrared spectroscopy, Unified Parkinson's Disease Rating Scale (UPDRS) scores, neurotransmitter levels, as well as the immediate effects of acupuncture in patients with PD.

RESULTS

The participants tended to walk with hypometric gait (high cadence, short steps) overground. After acupuncture treatment, those in the intervention group showed a significant reduction in cadence and the UPDRS scores involving "walking and balance" compared with those in the control group (P = .004 and P = .020, respectively); the stride, swing, and single support times were significantly increased (P = .006, P = .001, and P = .001, respectively). Oxyhemoglobin levels in the intervention group while walking on a treadmill were significantly increased in the prefrontal and supplementary motor areas. The oxyhemoglobin levels in the prefrontal cortex and swing time revealed significant positive correlations.

CONCLUSIONS

Our findings indicated that acupuncture tended to improve hypometric gait and rearranged activation of the cerebral cortex. Thus, acupuncture may be a useful complementary treatment for gait disturbance, including hypometric gait, in patients with PD. Trial Registration Number. Clinical Research Information Service (KCT0002603), https://cris.nih.go.kr/cris/index.jsp.

New Sensor and Wearable Technologies to Aid in the Diagnosis and Treatment Monitoring of Parkinson's Disease

Parkinson's disease (PD) is a degenerative disorder of the brain characterized by the impairment of the nigrostriatal system. This impairment leads to specific motor manifestations (i.e., bradykinesia, tremor, and rigidity) that are assessed through clinical examination, scales, and patient-reported outcomes. New sensor-based and wearable technologies are progressively revolutionizing PD care by objectively measuring these manifestations and improving PD diagnosis and treatment monitoring. However, their use is still limited in clinical practice, perhaps because of the absence of external validation and standards for their continuous use at home. In the near future, these systems will progressively complement traditional tools and revolutionize the way we diagnose and monitor patients with PD.

Gait asymmetry in glucocerebrosidase mutation carriers with Parkinson's disease

BACKGROUND

GBA mutation carriers with PD (PD-GBA) are at higher risk of cognitive decline, but there is limited data regarding whether there are differences in gait dysfunction between GBA mutation and non-mutation carriers with PD.

OBJECTIVES/METHODS

The primary aim of this study was to use quantitative inertial sensor-based gait analysis to compare gait asymmetry in 17 PD-GBA subjects, 17 non-mutation carriers with PD, and 15 healthy control subjects using parameters that had gait laterality and were markers of bradykinesia, in particular arm swing velocity and arm swing range of motion and stride length.

RESULTS

Arm swing velocity was more symmetric in PD-GBA subjects vs. non-mutation carriers in the OFF state (12.5 +/- 8.3 vs. 22.9 +/- 11.8%, respectively, p = 0.018). In the ON-medication state, non-mutation carriers with PD, but not PD-GBA subjects, exhibited arm swing velocity (16.8 +/- 8.6 vs. 22.9 +/- 11.8%, p = 0.006) and arm range of motion (26.7 +/- 16.3 vs. 33.4 +/- 18.6%, p = 0.02) that was more asymmetric compared with the OFF-medication state.

CONCLUSIONS

In the OFF medication state, arm swing velocity asymmetry may be a useful parameter in helping to distinguish GBA mutation carriers with PD from non-mutation carriers.

[Assessment of walking function in neurological practice]

An accurate diagnosis of the existing defect of motor function in patients with neurological pathology is necessary for the optimal formulation of the rehabilitation program, selection of drug therapy and evaluation of the effectiveness of treatment. In current clinical practice, clinical scales such as the Dynamic Gait Index, the Rivermid Mobility Index, the Hauser Walk Index, the Stand Up and Go Test, the MDS-UPDRS III are used most often to assess walking function. Evaluation of walking function using valid scales is very accessible, however, it has such a disadvantage as subjectivity. That's why the study of motor functions by instrumental methods gains more prominence. The most well-known methods of objective walking assessment include an analysis of human movements using accelerometers, three-dimensional video analysis, sub-metric, goniometric and impregnation methods. Each of these methods has both advantages and disadvantages. The main requirement to objective methods of assessing walking functions in neurological pathology is the universality of the complex (the accuracy of measurements, regardless of the type of walking disorder), the ability to determine both temporal and spatial characteristics of the step, the ease of use. Considering these requirements, the use of the 'Induction Analyzer of the kinematic parameters of walking' seems promising in the diagnosis of motor disorders.

Which Gait Parameters and Walking Patterns Show the Significant Differences Between Parkinson's Disease and Healthy Participants?

This study investigated the difference in the gait of patients with Parkinson’s disease (PD), age-matched controls and young controls during three walking patterns. Experiments were conducted with 24 PD, 24 age-matched controls and 24 young controls, and four gait intervals were measured using inertial measurement units (IMU). Group differences between the mean and variance of the gait parameters (stride interval, stance interval, swing interval and double support interval) for the three groups were calculated and statistical significance was tested. The results showed that the variance in each of the four gait parameters of PD patients was significantly higher compared with the controls, irrespective of the three walking patterns. This study showed that the variance of any of the gait interval parameters obtained using IMU during any of the walking patterns could be used to differentiate between the gait of PD and control people.

Development and Validation of Ambulosono: A Wearable Sensor for Bio-Feedback Rehabilitation Training

Wearable technology-based measurement systems hold potential for the therapeutic and rehabilitation management of patients with various chronic diseases. The purpose of this study was to assess the accuracy and test–retest reliability of a new-generation wearable sensor-based system, dubbed Ambulosono, for bio-feedback training. The Ambulosono sensor system was cross-validated by comparing its functionality with the iPod touch (4th generation) sensor system. Fifteen participants underwent a gait test to measure various gait parameters while wearing both the iPod-based and Ambulosono sensors simultaneously. The physically measured values (i.e., the true values) of step length, distance traveled, velocity, and cadence were then compared to those obtained via the two-sensor systems using the same calculation algorithms. While the mean percentage error was <10% for all measured parameters, and the intra-class correlation coefficient revealed a high level of agreement between trials for both sensor systems, it was found that the Ambulosono sensor system outperformed the iPod-based system in some respects. The Ambulosono sensor system possessed both reliability and accuracy in obtaining gait parameter measurements, which suggests it can serve as an economical alternative to the iPod-based system that is currently used in various clinical rehabilitation programs.

Five-Year Clinical Outcomes of Local versus General Anesthesia Deep Brain Stimulation for Parkinson's Disease

Background

Studies comparing long-term outcomes between general anesthesia (GA) and local anesthesia (LA) for STN-DBS in Parkinson's disease (PD) are lacking. Whether patients who received STN-DBS in GA could get the same benefit without compromising electrophysiological recording is debated.

Methods

We compared five-year outcomes for different anesthetic methods (GA vs LA) during STN-DBS for PD. Thirty-six consecutive PD patients with similar preoperative characteristics, including age, disease duration, and severity, underwent the same surgical procedures except the GA (n=22) group with inhalational anesthesia and LA (n=14) with local anesthesia during microelectrode recording and intraoperative macrostimulation test. Surgical outcome evaluations included Unified Parkinson's Disease Rating Scale (UPDRS), Mini-Mental Status Examinations, and the Beck Depression Inventory. Stimulation parameters and coordinates of STN targeting were also collected.

Results

Both groups attained similar benefits in UPDRS part III from STN-DBS (GA 43.2 ± 14.1% vs. LA 46.8 ± 13.8% decrease, p=0.45; DBS on/Med off vs. DBS off/Med off) and no difference in reduction of levodopa equivalent doses (GA 47.56 ± 18.98% vs. LA 51.37 ± 31.73%, p=0.51) at the five-year follow-up. In terms of amplitude, frequency, and pulse width, the stimulation parameters used for DBS were comparable, and the coordinates of preoperative targeting and postoperative electrode tip were similar between two groups. There was no difference in STN recording length as well. Significantly less number of MER tracts in GA was found (p=0.04). Adverse effects were similar in both groups.

Conclusions

Our study confirmed that STN localization with microelectrode recording and patient comfort could be achieved based on equal effectiveness and safety of STN-DBS under GA compared with LA.

Three-Dimensional Balance Training Using Visual Feedback on Balance and Walking Ability in Subacute Stroke Patients: A Single-Blinded Randomized Controlled Pilot Trial

BACKGROUND

Trunk-activating exercises for balance are important because trunk weakness is relevant to the functional performance of individuals with stroke. This study aimed to explore the effects of three-dimensional balance training using visual feedback on balance and walking ability in subacute stroke patients.

METHODS

Twenty-four participants with subacute stroke were randomly assigned to the experimental or control group. Each group underwent twenty sessions (30 min/day, 5 days/week for 4 weeks). Patients were assessed using the Berg balance scale, gait parameters (gait speed, cadence, step length, and double-limb support period) using GAITRite, and activity-specific balance confidence score, before and after the intervention.

RESULTS

The three-dimensional balance training using visual feedback exhibited greater changes in the Berg balance scale, gait speed, cadence, step length, double-limb support period, and activity-specific balance confidence compared with the control group. Statistical analyses showed significant differences in Berg balance scale (P = .012; 95% CI, 2.585-6.415), gait speed (P = .001; 95% CI, .079-.155), cadence (P = .001; 95% CI, 1.622-4.392), step length (P = .003; 95% CI, 1.864-3.908), double-limb support period (P = .003; 95% CI, -3.259 to -0.761) and activity-specific confidence (P = .008; 95% CI, 6.964-14.036) between groups.

CONCLUSION

Three-dimensional balance training using visual feedback may be more effective than conventional training in improving balance, walking ability, and activity-specific balance confidence in patients with subacute stroke.

Evaluation of smartphone-based testing to generate exploratory outcome measures in a phase 1 Parkinson's disease clinical trial

BACKGROUND

Ubiquitous digital technologies such as smartphone sensors promise to fundamentally change biomedical research and treatment monitoring in neurological diseases such as PD, creating a new domain of digital biomarkers.

OBJECTIVES

The present study assessed the feasibility, reliability, and validity of smartphone-based digital biomarkers of PD in a clinical trial setting.

METHODS

During a 6-month, phase 1b clinical trial with 44 Parkinson participants, and an independent, 45-day study in 35 age-matched healthy controls, participants completed six daily motor active tests (sustained phonation, rest tremor, postural tremor, finger-tapping, balance, and gait), then carried the smartphone during the day (passive monitoring), enabling assessment of, for example, time spent walking and sit-to-stand transitions by gyroscopic and accelerometer data.

RESULTS

Adherence was acceptable: Patients completed active testing on average 3.5 of 7 times/week. Sensor-based features showed moderate-to-excellent test-retest reliability (average intraclass correlation coefficient = 0.84). All active and passive features significantly differentiated PD from controls with P < 0.005. All active test features except sustained phonation were significantly related to corresponding International Parkinson and Movement Disorder Society-Sponsored UPRDS clinical severity ratings. On passive monitoring, time spent walking had a significant (P = 0.005) relationship with average postural instability and gait disturbance scores. Of note, for all smartphone active and passive features except postural tremor, the monitoring procedure detected abnormalities even in those Parkinson participants scored as having no signs in the corresponding International Parkinson and Movement Disorder Society-Sponsored UPRDS items at the site visit.

CONCLUSIONS

These findings demonstrate the feasibility of smartphone-based digital biomarkers and indicate that smartphone-sensor technologies provide reliable, valid, clinically meaningful, and highly sensitive phenotypic data in Parkinson's disease. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Recuperation of slow walking in de novo Parkinson's disease is more closely associated with increased cadence, rather than with expanded stride length

INTRODUCTION

Gait characteristics in the early stages of Parkinson's disease (PD) have been less investigated so far. Moreover, the levodopa effect on gait in early PD remains to be further elucidated. We prospectively designed the study to examine gait dynamics and effect of dopaminergic treatment in patients with de novo PD.

METHODS

Spatiotemporal parameters were measured in healthy controls and drug naïve patients with PD, using computerized analysis with GAITRite system during usual gait. In PD group, motor symptoms and gait parameters were examined in both drug naive and levodopa 100mg trial conditions.

RESULTS

Twenty four de novo PD patients and 27 healthy controls (matched for age, sex, and height) were selected for the study. Compared with the controls, patients with de novo PD showed the decrease in stride length, in both Med-OFF and Med-ON conditions. Notably, drug naïve patients with PD demonstrated slow walking velocity, whereas those with levodopa administration exhibited the increase of cadence by shortening stride time, which resulted in the improvement of gait speed. In addition, the stride length (gait hypokinesia) correlated with postural instability and gait difficulty subscore, but not with tremor, rigidity, bradykinesia, or total motor score.

CONCLUSION

As a compensatory mechanism of slow walking, we found that the increment in cadence (frequency) is more important than the increment in stride length (amplitude) in gait dynamics in de novo PD. Additionally, the results may indicate that gait hypokinesia in PD could be regarded as one of axial symptoms.

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.

Effects of robot-assisted gait training on spatiotemporal gait parameters and balance in patients with chronic stroke: A randomized controlled pilot trial

BACKGROUND

Body weight-supported treadmill training assisted by a robotic gait orthosis is a helpful tool for restoring a symmetrical gait pattern in people with gait discrepancies.

OBJECTIVE

This study's aim was to compare the effects of robot-assisted gait training (RAGT) versus treadmill gait training (TGT) on spatiotemporal gait parameters, balance, and activities-specific balance confidence with stroke patients.

METHODS

Eighteen participants with stroke were randomly assigned to RAGT or TGT. Each group underwent twenty sessions (1 h/d, 5 d/wk for 4 weeks). Patients were assessed with gait parameters (gait speed, cadence, step length, and double limb support period) using the GAITRite, the Berg Balance Scale (BBS) score, and the activities-specific balance confidence (ABC) score before and after the intervention.

RESULTS

Gait speed (P = 0.003), cadence (P = 0.002), step length (P = 0.004), the BBS score (P = 0.048), and the ABC score (P = 0.017) were significantly higher in the RAGT group than in the TGT group, while the double limb support period was significantly lower in the RAGT group (P = 0.043).

CONCLUSION

RAGT using Lokomat may be more effective than TGT in improving waking ability, balance, and balance confidence in patients with chronic stroke.

Instrumented gait analysis: a measure of gait improvement by a wheeled walker in hospitalized geriatric patients

Background

In an increasing aging society, reduced mobility is one of the most important factors limiting activities of daily living and overall quality of life. The ability to walk independently contributes to the mobility, but is increasingly restricted by numerous diseases that impair gait and balance. The aim of this cross-sectional observation study was to examine whether spatio-temporal gait parameters derived from mobile instrumented gait analysis can be used to measure the gait stabilizing effects of a wheeled walker (WW) and whether these gait parameters may serve as surrogate marker in hospitalized patients with multifactorial gait and balance impairment.

Methods

One hundred six patients (ages 68–95) wearing inertial sensor equipped shoes passed an instrumented walkway with and without gait support from a WW. The walkway assessed the risk of falling associated gait parameters velocity, swing time, stride length, stride time- and double support time variability. Inertial sensor-equipped shoes measured heel strike and toe off angles, and foot clearance.

Results

The use of a WW improved the risk of spatio-temporal parameters velocity, swing time, stride length and the sagittal plane associated parameters heel strike and toe off angles in all patients. First-time users (FTUs) showed similar gait parameter improvement patterns as frequent WW users (FUs). However, FUs with higher levels of gait impairment improved more in velocity, stride length and toe off angle compared to the FTUs.

Conclusion

The impact of a WW can be quantified objectively by instrumented gait assessment. Thus, objective gait parameters may serve as surrogate markers for the use of walking aids in patients with gait and balance impairments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12984-017-0228-z) contains supplementary material, which is available to authorized users.

Measuring prefrontal cortical activity during dual task walking in patients with Parkinson's disease: feasibility of using a new portable fNIRS device

BACKGROUND

Many patients with Parkinson's disease (PD) have difficulties in performing a second task during walking (i.e., dual task walking). Functional near-infrared spectroscopy (fNIRS) is a promising approach to study the presumed contribution of dysfunction within the prefrontal cortex (PFC) to such difficulties. In this pilot study, we examined the feasibility of using a new portable and wireless fNIRS device to measure PFC activity during different dual task walking protocols in PD. Specifically, we tested whether PD patients were able to perform the protocol and whether we were able to measure the typical fNIRS signal of neuronal activity.

METHODS

We included 14 PD patients (age 71.2 ± 5.4 years, Hoehn and Yahr stage II/III). The protocol consisted of five repetitions of three conditions: walking while (i) counting forwards, (ii) serially subtracting, and (iii) reciting digit spans. Ability to complete this protocol, perceived exertion, burden of the fNIRS devices, and concentrations of oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin from the left and right PFC were measured.

RESULTS

Two participants were unable to complete the protocol due to fatigue and mobility safety concerns. The remaining 12 participants experienced no burden from the two fNIRS devices and completed the protocol with ease. Bilateral PFC O2Hb concentrations increased during walking while serially subtracting (left PFC 0.46 μmol/L, 95 % confidence interval (CI) 0.12-0.81, right PFC 0.49 μmol/L, 95 % CI 0.14-0.84) and reciting digit spans (left PFC 0.36 μmol/L, 95 % CI 0.03-0.70, right PFC 0.44 μmol/L, 95 % CI 0.09-0.78) when compared to rest. HHb concentrations did not differ between the walking tasks and rest.

CONCLUSIONS

These findings suggest that a new wireless fNIRS device is a feasible measure of PFC activity in PD during dual task walking. Future studies should reduce the level of noise and inter-individual variability to enable measuring differences in PFC activity between different dual walking conditions and across health states.

Influence of leash side and handlers on pressure mat analysis of gait characteristics in small-breed dogs

OBJECTIVE

To characterize the gait of small-breed dogs walked on a pressure walkway by handlers moving at a metronome-set tempo and to determine the influence of handler and leash side on gait characteristics.

DESIGN

Prospective study.

ANIMALS

5 healthy adult small-breed dogs weighing < 11.4 kg (25 lb).

PROCEDURES

Dogs were walked by each of 5 handlers moving at a metronome-set tempo (100 beats/min). Velocity, cadence, stance time, number of activated sensors, total pressure index (TPI), left or right hind reach, and symmetry indices were obtained with the leash on the left and right sides of each dog for each handler.

RESULTS

Coefficients of variation for TPI and stance time approximated 30%, whereas coefficients of variation for symmetry indices remained < 20%. Changing handlers and leash side did not influence hind limb variables. Changing handlers influenced the TPI of the forelimbs, inducing changes of up to 8%. Leash side accounted for 12% and 14% of the variation in symmetry indices of TPI and number of sensors activated between forelimbs, respectively (mean alterations for recorded variables, 9%).

CONCLUSIONS AND CLINICAL RELEVANCE

Symmetry indices appeared to vary less than variables obtained for individual dog limbs, and it may therefore be advantageous to determine those indices during large trials. Handlers or leash side may be changed in studies focusing on dogs' hind limbs without affecting results. Use of symmetry indices is recommended in forelimb studies requiring multiple handlers. Pressure walkway analyses of the forelimbs should include equal distribution of left- and right-sided leash-led trials, given that small-breed dogs tended to shift weight toward the forelimb opposite the leash.

A systematic review of the characteristics and validity of monitoring technologies to assess Parkinson's disease

Background

There is growing interest in having objective assessment of health-related outcomes using technology-based devices that provide unbiased measurements which can be used in clinical practice and scientific research. Many studies have investigated the clinical manifestations of Parkinson’s disease using such devices. However, clinimetric properties and clinical validation vary among the different devices.

Methods

Given such heterogeneity, we sought to perform a systematic review in order to (i) list, (ii) compare and (iii) classify technological-based devices used to measure motor function in individuals with Parkinson's disease into three groups, namely wearable, non-wearable and hybrid devices. A systematic literature search of the PubMed database resulted in the inclusion of 168 studies. These studies were grouped based on the type of device used. For each device we reviewed availability, use, reliability, validity, and sensitivity to change. The devices were then classified as (i) ‘recommended’, (ii) ‘suggested’ or (iii) ‘listed’ based on the following criteria: (1) used in the assessment of Parkinson’s disease (yes/no), (2) used in published studies by people other than the developers (yes/no), and (3) successful clinimetric testing (yes/no).

Results

Seventy-three devices were identified, 22 were wearable, 38 were non-wearable, and 13 were hybrid devices. In accordance with our classification method, 9 devices were ‘recommended’, 34 devices were ‘suggested’, and 30 devices were classified as ‘listed’. Within the wearable devices group, the Mobility Lab sensors from Ambulatory Parkinson’s Disease Monitoring (APDM), Physilog®, StepWatch 3, TriTrac RT3 Triaxial accelerometer, McRoberts DynaPort, and Axivity (AX3) were classified as ‘recommended’. Within the non-wearable devices group, the Nintendo Wii Balance Board and GAITRite® gait analysis system were classified as ‘recommended’. Within the hybrid devices group only the Kinesia® system was classified as ‘recommended’.

Electronic supplementary material

The online version of this article (doi:10.1186/s12984-016-0136-7) contains supplementary material, which is available to authorized users.

Quantitative measurement of Parkinsonian gait from walking in monocular image sequences using a centroid tracking algorithm

Parkinson's disease (PD) is a neurodegenerative disease of the central nervous system that results from the degeneration of dopaminergic neurons in the substantia nigra. Abnormal gait begins in the early stage and becomes severe as the disease progresses; therefore, the assessment of gait becomes an important issue in evaluating the progression of PD and the effectiveness of treatment. To provide a clinically useful gait assessment in environments with budget and space limitations, such as a small clinic or home, we propose and develop a portable method utilizing the monocular image sequences of walking to track and analyze a Parkinsonian gait pattern. In addition, a centroid tracking algorithm is developed and used here to enhance the method of quantifying kinematic gait parameters of PD in different states. Twelve healthy subjects and twelve mild patients with PD participate in this study. This method requires one digital video camera and subjects with two joint markers attached on the fibula head and the lateral malleolus of the leg. All subjects walk with a natural pace in front of a video camera during the trials. Results of our study demonstrate the stride length and walking velocity significantly decrease in PD without drug compared to PD with drug in both proposed method and simultaneous gait assessment performed by GAITRite(®) system. In gait initiation, step length and swing velocity also decrease in PD without drug compared to both PD with drug and controls. Our results showed high correlation in gait parameters between the two methods and prove the reliability of the proposed method. With the proposed method, quantitative measurement and analysis of Parkinsonian gait could be inexpensive to implement, portable within a small clinic or home, easy to administer, and simple to interpret. Although this study is assessed Parkinsonian gait, the proposed method has the potential to help clinicians and researchers assess the gait of patients with other neuromuscular diseases, such as traumatic brain injury and stroke patients.

Validation of an Accelerometer to Quantify a Comprehensive Battery of Gait Characteristics in Healthy Older Adults and Parkinson's Disease: Toward Clinical and at Home Use

Measurement of gait is becoming important as a tool to identify disease and disease progression, yet to date its application is limited largely to specialist centers. Wearable devices enables gait to be measured in naturalistic environments, however questions remain regarding validity. Previous research suggests that when compared with a laboratory reference, measurement accuracy is acceptable for mean but not variability or asymmetry gait characteristics. Some fundamental reasons for this have been presented, (e.g., synchronization, different sampling frequencies) but to date this has not been systematically examined. The aims of this study were to: 1) quantify a comprehensive range of gait characteristics measured using a single triaxial accelerometer-based monitor; 2) examine outcomes and monitor performance in measuring gait in older adults and those with Parkinson's disease (PD); and 3) carry out a detailed comparison with those derived from an instrumented walkway to account for any discrepancies. Fourteen gait characteristics were quantified in 30 people with incident PD and 30 healthy age-matched controls. Of the 14 gait characteristics compared, agreement between instruments was excellent for four (ICCs 0.913-0.983); moderate for four (ICCs 0.508-0.766); and poor for six characteristics (ICCs 0.637-0.370). Further analysis revealed that differences reflect an increased sensitivity of accelerometry to detect motion, rather than measurement error. This is most likely because accelerometry measures gait as a continuous activity rather than discrete footfall events, per instrumented tools. The increased sensitivity shown for these characteristics will be of particular interest to researchers keen to interpret "real-world" gait data. In conclusion, use of a body-worn monitor is recommended for the measurement of gait but is likely to yield more sensitive data for asymmetry and variability features.

Comparison of programs for determining temporal-spatial gait variables from instrumented walkway data: PKmas versus GAITRite

Background

Measurement of temporal-spatial gait variables is common in aging research with several methods available. This study investigated the differences in temporal-spatial gait outcomes derived from two different programs for processing instrumented walkway data.

Method

Data were collected with GAITRite® hardware from 86 healthy older people and 44 older people four months following surgical repair of hip fracture. Temporal-spatial variables were derived using both GAITRite® and PKmas® processing programs from the same raw footfall data.

Results

The mean differences between the two programs for most variables were negligible, including for Speed (mean difference 0.3 ± 0.6 cm/sec, or 0.3% of the mean GAITRite® Speed). The mean absolute percentage difference for all 18 gait variables examined ranged from 0.04% for Stride Duration to 66% for Foot Angle. The ICCs were almost perfect (≥0.99) for all variables apart from Base Width, Foot Angle, Stride Length Variability, Step Length Variability, Step Duration Variability and Step Width Variability, which were all never-the-less above 0.84. There were systematic differences for Base Width (PKmas® values 1.6 cm lower than GAITRite®) and Foot Angle (PKMAS® values 0.7° higher than GAITRite®). The differences can be explained by the differences in definitions and calculations between the programs.

Conclusions

The study demonstrated that for most variables the outcomes from both programs can be used interchangeably for evaluation of gait among older people collected with GAITRite® hardware. However, validity and reliability for Base Width and Foot Angle derived by PKMAS® would benefit from further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-542) contains supplementary material, which is available to authorized users.

Automated gait and balance parameters diagnose and correlate with severity in Parkinson disease

OBJECTIVE

To assess the suitability of instrumented gait and balance measures for diagnosis and estimation of disease severity in PD.

METHODS

Each subject performed iTUG (instrumented Timed-Up-and-Go) and iSway (instrumented Sway) using the APDM(®) Mobility Lab. MDS-UPDRS parts II and III, a postural instability and gait disorder (PIGD) score, the mobility subscale of the PDQ-39, and Hoehn & Yahr stage were measured in the PD cohort. Two sets of gait and balance variables were defined by high correlation with diagnosis or disease severity and were evaluated using multiple linear and logistic regressions, ROC analyses, and t-tests.

RESULTS

135 PD subjects and 66 age-matched controls were evaluated in this prospective cohort study. We found that both iTUG and iSway variables differentiated PD subjects from controls (area under the ROC curve was 0.82 and 0.75 respectively) and correlated with all PD severity measures (R(2) ranging from 0.18 to 0.61). Objective exam-based scores correlated more strongly with iTUG than iSway. The chosen set of iTUG variables was abnormal in very mild disease. Age and gender influenced gait and balance parameters and were therefore controlled in all analyses.

INTERPRETATION

Our study identified sets of iTUG and iSway variables which correlate with PD severity measures and differentiate PD subjects from controls. These gait and balance measures could potentially serve as markers of PD progression and are under evaluation for this purpose in the ongoing NIH Parkinson Disease Biomarker Program.

Spatiotemporal gait parameters for patients with Parkinson's disease compared with normal individuals

BACKGROUND

Gait initiation is a major motor problem for patients with Parkinson's disease (PD). To understand the gait initiation in patients with PD, fluctuation on the first three steps of initiation was examined

METHODS

Force distribution measurement platform was used to record gait initiation in 10 patients with PD and healthy participants. Step length, step time and step width, as well as its coefficient of variation (CV) were investigated

RESULTS

The findings demonstrated significant main effect of group on step length (p < 0.001), step time (p = 0.034) and step width (p = 0.002), significant main effect of step on step time (p < 0.001) and step width (p < 0.001). No interaction between group and step (p > 0.05) was found on the variables. Compared with healthy participants, patients with PD showed significantly shorter step length in the first (p < 0.001), second (p = 0.001) and third (p = 0.001) steps and longer step time in the second step (p < 0.001). No difference in CV (p > 0.05) of the variables between groups comparison. Both groups had significant longer step time in the first step compared with the second step (PD, p < 0.001; healthy participants, p < 0.001) and the third steps (PD, p < 0.001; healthy participants, p < 0.001). They demonstrated significant wider step width in the first step when compared with the second step (PD, p = 0.043; healthy participants, p < 0.001) and the third steps (PD, p = 0.002; healthy participants, p < 0.001).

CONCLUSION

Patients with PD showed shorter step length of all steps, longer step time in the second step and similar step width when compared with healthy participants. Among the three steps, both groups demonstrated longer step time and wider step width in the first step when compared with other two step.

60-Hz frequency effect on gait in Parkinson's disease with subthalamic nucleus deep brain stimulation

OBJECTIVE

Gait dysfunction is common in advancing Parkinson's disease and has a disappointing response to dopamine replacement and subthalamic nucleus deep brain stimulation programming parameters. Low-frequency stimulation, less than 130 Hz in combination with increased voltage, has been shown to decrease freezing episodes and number of steps with little impact on overall performance measured by the Unified Parkinson's Disease Rating Scale. This was in the setting of delivering the same total energy, which required both a change in voltage and frequency. We wanted to determine if the benefit came from low frequency alone.

MATERIALS AND METHODS

We enrolled 20 Parkinson's patients who were at least three months in postbilateral subthalamic deep brain stimulation and reported gait changes. Subjects held their Parkinson's medications overnight, and following a baseline evaluation, they were randomly assigned to both 60 and 130 Hz stimulation in a blinded fashion with all other parameters held constant. Each subject was set at each frequency twice during the study, with a 60-min stimulation interval prior to each gait evaluation.

RESULTS

There was no significant difference between the two frequencies, with the primary outcome measure of stride length. Two of the 20 patients reported a significant subjective improvement in their gait with no statistical difference in their outcomes. There also was less tremor control at 60 Hz.

CONCLUSION

We were unable to demonstrate improved gait with lower frequency stimulation as suggested by prior studies. This may have been because of the decreased energy delivered from the lower frequency and unchanged voltage.

Gait dysfunction in Parkinson's disease and normal pressure hydrocephalus: a comparative study

Our objectives were to characterize gait dysfunction in Parkinson's disease (PD) and normal pressure hydrocephalus (NPH) patients, in a comparative analysis. We used a walking test to determine gait velocity (GV), stride length (SL), stride cadence and the presence of frontal (FG) and sub-cortical hypokinetic gait (SHG) features. Equilibrium was tested with the shoulder tug test (STT). These variables were used in cluster analysis, to classify subjects according to gait dysfunction. PD patients were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (HY) scale. NPH patients were reassessed after high volume lumbar puncture (LP). NPH (n = 35) and PD (n = 40) patients had lower SL, GV and STT scores than controls (n = 30). NPH patients had worse results in SL, GV and STT than PD and a higher frequency of both FG and SHG features, compared to PD and the control groups. We found a severe/moderate gait dysfunction cluster, formed by 33 NPH patients and 11 PD patients, and a normal/mild dysfunction cluster, comprising 2 NPH, 29 PD patients and all control subjects. PD patients in the first cluster had worse UPDRS (except for tremor) and HY scores. In NPH patients, all gait variables improved after LP, although not to the controls level. PD and NPH gait was similarly characterized by loss of balance, slowness and small steps, although NPH patients performed worse. In PD patients, gait dysfunction comparable to that of NPH patients was associated with worse motor stage and the akinetic-rigid variant.

Reliability of the non-instrumented walk test in persons with Parkinson's disease

PURPOSE

To study the reliability of a Non-Instrumented Walk Test in individuals with Parkinson's disease (PD).

METHOD

Thirty individuals (21 Males) with PD were studied. Their mean age was 68.90 ± 9.28 years. The average time since diagnosis was 8.75 ± 5.68 years. The reliability of the manual Non-Instrumented Walk Test was studied while "OFF" and "ON" dopaminergic medication. Subjects walked at their self-selected, usual speed during a Non-Instrumented Walk Test and while walking on a computerized instrumented walkway. Intraclass correlation coefficients (ICCs) were calculated and means were compared for three gait parameters as measured by the two methods.

RESULTS

During "OFF" medication testing, ICCs between the Non-Instrumented Walk Test and the instrumented measures for gait speed, cadence and stride length were 0.96 (p < 0.0005), 0.72 (p = 0.001) and 0.97 (p < 0.0005), respectively. During "ON" medication testing, the ICCs were 0.96 (p < 0.0005), 0.86 (p < 0.0005) and 0.96 (p < 0.0005), respectively. The means of the non-instrumented measures tended to be lower than those obtained on the instrumented walkway.

CONCLUSIONS

The Non-Instrumented Walk Test is a quick, simple and inexpensive gait evaluation for individuals with PD. The method is sufficiently reliable to be used clinically in this population during different medication cycles.

IMPLICATIONS FOR REHABILITATION

• The Non-Instrumented Walk Test in individuals with PD is reliable. • Results supported the use of the measure. This simple walk test is quick and easy to administer in both clinical and community settings.

Medication improves balance and complex gait performance in Parkinson disease

Gait and balance impairments in people with Parkinson disease (PD) may lead to falls and serious injuries. Therefore, it is critical to improve our understanding of the nature of these impairments, including how they respond to prescribed anti-Parkinson medication. This is particularly important for complex balance and gait tasks that may be associated with falls. We evaluated motor function, functional balance, and gait performance during various gait tasks in 22 people with PD OFF and ON medication (PD OFF, PD ON) and 20 healthy older adults. Although MDS-UPDRS-III score, Berg Balance Scale, Mini-Balance Evaluations Systems test, and Timed-Up-and-Go improved in PD with medication, impairments persisted in all measures on medication, compared to controls. Dual task Timed-Up-and-Go did not improve with medication, and PD ON required more time than controls. Gait velocity and stride length improved similarly with medication in PD across forward, fast, backward, dual task forward, and dual task backward gait tasks. Cadence did not change with medication, nor did it differ between PD ON and controls. Velocity and stride length were reduced in PD ON compared to controls. Velocity reductions in PD ON during fast gait were cadence-mediated, while velocity reductions in backward gait were stride length-mediated. Our results suggest functional balance improves with medication in PD and gait performance improves with medication, regardless of task complexity. Remaining impairments on medication highlight the need to examine additional therapeutic options for individuals with PD to reduce the risk of falls.

A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulation

Gait freezing is an episodic arrest of locomotion due to an inability to take normal steps. Pedunculopontine nucleus stimulation is an emerging therapy proposed to improve gait freezing, even where refractory to medication. However, the efficacy and precise effects of pedunculopontine nucleus stimulation on Parkinsonian gait disturbance are not established. The clinical application of this new therapy is controversial and it is unknown if bilateral stimulation is more effective than unilateral. Here, in a double-blinded study using objective spatiotemporal gait analysis, we assessed the impact of unilateral and bilateral pedunculopontine nucleus stimulation on triggered episodes of gait freezing and on background deficits of unconstrained gait in Parkinson’s disease. Under experimental conditions, while OFF medication, Parkinsonian patients with severe gait freezing implanted with pedunculopontine nucleus stimulators below the pontomesencephalic junction were assessed during three conditions; off stimulation, unilateral stimulation and bilateral stimulation. Results were compared to Parkinsonian patients without gait freezing matched for disease severity and healthy controls. Pedunculopontine nucleus stimulation improved objective measures of gait freezing, with bilateral stimulation more effective than unilateral. During unconstrained walking, Parkinsonian patients who experience gait freezing had reduced step length and increased step length variability compared to patients without gait freezing; however, these deficits were unchanged by pedunculopontine nucleus stimulation. Chronic pedunculopontine nucleus stimulation improved Freezing of Gait Questionnaire scores, reflecting a reduction of the freezing encountered in patients’ usual environments and medication states. This study provides objective, double-blinded evidence that in a specific subgroup of Parkinsonian patients, stimulation of a caudal pedunculopontine nucleus region selectively improves gait freezing but not background deficits in step length. Bilateral stimulation was more effective than unilateral.

Gait feature extraction in Parkinson's disease using low-cost accelerometers

The clinical hallmarks of Parkinson's disease (PD) are movement poverty and slowness (i.e. bradykinesia), muscle rigidity, limb tremor or gait disturbances. Parkinson's gait includes slowness, shuffling, short steps, freezing of gait (FoG) and/or asymmetries in gait. There are currently no validated clinical instruments or device that allow a full characterization of gait disturbances in PD. As a step towards this goal, a four accelerometer-based system is proposed to increase the number of parameters that can be extracted to characterize parkinsonian gait disturbances such as FoG or gait asymmetries. After developing the hardware, an algorithm has been developed, that automatically epoched the signals on a stride-by-stride basis and quantified, among others, the gait velocity, the stride time, the stance and swing phases, the single and double support phases or the maximum acceleration at toe-off, as validated by visual inspection of video recordings during the task. The results obtained in a PD patient and a healthy volunteer are presented. The FoG detection will be improved using time-frequency analysis and the system is about to be validated with a state-of-the-art 3D movement analysis system.

Variable initial swing side and prolonged double limb support represent abnormalities of the first three steps of gait initiation in patients with Parkinson's disease with freezing of gait

This study investigated abnormalities of the first three steps of gait initiation in patients with Parkinson’s disease without freezing of gait (PD − FOG) and investigated which abnormalities are related to FOG. Seven PD − FOG and seven age-matched healthy controls performed self-generated or cue-triggered gait initiation. Data for PD patients with FOG (PD + FOG) were cited from a previous study using a procedure similar to that used in the present study. Gait initiation was abnormal, and external cue normalized some abnormalities in PD − FOG. The initial swing side was fairly consistent among the trials in both PD − FOG and in healthy controls, although the initial swing side was inconsistent in PD + FOG. The duration of the first double limb support (DLS) was the only parameter that depends on FOG severity and that was abnormal in PD + FOG but was not abnormal in PD − FOG. The variability of the initial swing side and prolonged first DLS are abnormalities specifically related to FOG.

Single and dual task gait training in people with Parkinson's disease: a protocol for a randomised controlled trial

Background

Difficulty performing more than one task at a time (dual tasking) is a common and disabling problem experienced by people with Parkinson disease (PD). If asked to perform another task when walking, people with PD often take shorter steps or walk more slowly. Currently there is uncertainty about whether clinicians should teach people with PD to avoid dual tasking or whether they should encourage them to practice dual tasking with the hope that practice will lead to enhanced performance. This study will address this issue by comparing single to dual task gait training.

Methods and design

A prospective randomised clinical trial is being conducted. Sixty participants with idiopathic PD will be recruited, provided they score I-IV on the modified Hoehn and Yahr (1967) scale, and fulfil other inclusion criteria. Participants will be randomly allocated to either a single or dual task gait training group. Both groups will receive 12 hours of walking training over 4 weeks. The single task group will undertake gait training with cueing strategies to increase step length. The dual task group will train to improve step length when walking and performing a variety of added tasks. Both groups will receive a tailored home program for 6 months. Blinded assessors will conduct four assessments: two baseline assessments, one post intervention and one at 6 months follow-up. The primary outcome measure will be step length when dual tasking over 8 m. Secondary outcome measures include: spatiotemporal gait parameters when walking under single and dual task conditions, measures of executive function, the timed up and go test, measures of community mobility, and quality of life. All analyses will be based on intention to treat principle.

Discussion

This trial will examine the immediate and longer term effect of dual task walking training as compared to single task training in people with idiopathic PD, at the impairment, activity, and participation levels. It has the potential to identify a new intervention that may improve and maintain walking beyond the laboratory. The results of this trial will provide guidance for clinicians in the development of walking training programs for people with PD.

Trial Registration

ACTRN12609000791235

Abnormalities of the first three steps of gait initiation in patients with Parkinson's disease with freezing of gait

The purpose of this study was to investigate abnormalities of the first three steps of gait initiation in patients with Parkinson's disease (PD) with freezing of gait (FOG). Ten PD patients with FOG and 10 age-matched healthy controls performed self-generated gait initiation. The center of pressure (COP), heel contact positions, and spatiotemporal parameters were estimated from the vertical pressures on the surface of the force platform. The initial swing side of gait initiation was consistent among the trials in healthy controls but not among the trials in PD patients. The COP and the heel contact position deviated to the initial swing side during the first step, and the COP passed medial to each heel contact position during the first two steps in PD patients. Medial deviation of the COP from the first heel contact position had significant correlation with FOG questionnaire item 5. These findings indicate that weight shifting between the legs is abnormal and that medial deviation of the COP from the first heel contact position sensitively reflects the severity of FOG during the first three steps of gait initiation in PD patients with FOG.

Effects of a short duration, high dose contact improvisation dance workshop on Parkinson disease: a pilot study

OBJECTIVES

This study explored the feasibility and possible benefits of contact improvisation (CI) as an exercise intervention for individuals with PD.

DESIGN

This was an uncontrolled pilot study.

INTERVENTION

Eleven people with PD (H&Y=2.4 ± 0.4) participated in a workshop of 10 1.5-h CI classes over 2 weeks, dancing with previously trained student CI dancers.

MAIN OUTCOME MEASURES

Measures of disease severity, balance, functional mobility, and gait were compared 1 week before and after the workshop.

RESULTS

Participants demonstrated improvements on the Unified Parkinson Disease Rating Scale-Motor Subsection and Berg balance scores, along with increased swing and decreased stance percentages during walking. Backward step length also increased. Participants expressed a high level of enjoyment and interest in taking future CI classes.

CONCLUSIONS

This pilot study supports the feasibility of CI as an intervention to address mobility limitations associated with PD.

Can people with Parkinson's disease improve dual tasking when walking?

BACKGROUND

Gait disorders in people with Parkinson's disease (PD) are accentuated when they perform another task simultaneously. This study examines whether practice enables people with PD to walk with large steps while performing added tasks, and to determine if training people with PD to walk with added working memory tasks leads to improvements in gait when walking and performing other tasks simultaneously.

METHODS

Walking patterns were recorded pre and post a 20min dual task training session in 20 people with PD. Participants performed a series of 10m walking trials under seven conditions: gait only, and with six different added tasks varying by task type (e.g. motor, cognitive), domain (e.g. postural, manual manipulation, language, calculation, auditory, visuospatial), and difficulty level. Dual task training aimed to improve step length while simultaneously undertaking a variety of language and counting working memory tasks that were different to those used in assessment.

RESULTS

Following training, step length increased when performing five of the six added tasks, indicating transfer of dual task training when walking occurred across task types and domains. Improvements in gait speed occurred in three of the six added tasks. When other gait variables were examined, such as step length variability, few improvements with training were found.

CONCLUSIONS

Training can lead to larger steps when walking under dual task conditions in people with PD. The gait variable emphasised during dual task training appears to be an important factor in enabling the transfer of training improvements across tasks.

Alternate rhythmic vibratory stimulation of trunk muscles affects walking cadence and velocity in Parkinson's disease

OBJECTIVE

During the administration of timed bilateral alternate vibration to homonymous leg or trunk muscles during quiet upright stance, Parkinsonian (PD) patients undergo cyclic antero-posterior and medio-lateral transfers of the centre of foot pressure. This event might be potentially exploited for improving gait in these patients. Here, we tested this hypothesis by applying alternate muscle vibration during walking in PD.

METHODS

Fifteen patients and 15 healthy subjects walked on an instrumented walkway under four conditions: no vibration (no-Vib), and vibration of tibialis anterior (TA-Vib), soleus (Sol-Vib) and erector spinae (ES-Vib) muscles of both sides. Trains of vibration (internal frequency 100 Hz) were delivered to right and left side at alternating frequency of 10% above preferred step cadence.

RESULTS

During vibration, stride length, cadence and velocity increased in both patients and healthy subjects, significantly so for ES-Vib. Stance and swing time tended to decrease. Width of support base increased with Sol-Vib or TA-Vib, but was unaffected by ES-Vib.

CONCLUSIONS

Alternate ES vibration enhances gait velocity in PD. The stronger effect of ES over leg muscle vibration might depend on the relevance of the proprioceptive inflow from the trunk muscles and on the absence of adverse effects on the support base width.

SIGNIFICANCE

Trunk control is defective in PD. The effect of timed vibratory stimulation on gait suggests the potential use of trunk proprioceptive stimulation for tuning the central pattern generators for locomotion in PD.