Which measures of physical function and motor impairment best predict quality of life in Parkinson's disease?

Effect of Group-Based Rehabilitation Combining Action Observation with Physiotherapy on Freezing of Gait in Parkinson's Disease

Freezing of gait (FoG) is among the most disabling symptoms of Parkinson's disease (PD) patients. Recent studies showed that action observation training (AOT) with repetitive practice of the observed actions represents a strategy to induce longer-lasting effects compared with standard physiotherapy. We investigated whether AOT may improve FoG and mobility in PD, when AOT is applied in a group-based setting. Sixty-four participants with PD and FoG were assigned to the experimental (AO) or control groups and underwent a 45-minute training session, twice a week, for 5 weeks. AOT consisted in physical training combined with action observation whereas the control group executed the same physical training combined with landscape-videos observation. Outcome measures (FoG questionnaire, Timed Up and Go test, 10-meter walking test, and Berg balance scale) were evaluated before training, at the end of training, and 4 weeks later (FU-4w). Both groups showed positive changes in all outcome measures at posttraining assessment. Improvements in FoG questionnaire, Timed Up and Go test, and Berg balance scale were retained at FU-4w evaluation only in the AOT group. AOT group-based training is feasible and effective on FoG and motor performance in PD patients and may be introduced as an adjunctive option in PD rehabilitation program.

Gait initiation is influenced by emotion processing in Parkinson's disease patients with freezing

BACKGROUND

Freezing of gait is a symptom that affects more than 50% of Parkinson's disease (PD) patients and increasing evidence suggests that nonmotor systems (i.e., limbic system) are involved in its underlying mechanisms.

OBJECTIVE

The objective of this study was to investigate whether gait initiation characteristics are influenced by emotional stimuli in patients with PD, with or without freezing of gait.

METHODS

A total of 44 participants, divided into 3 groups (15 PD patients with and 15 PD patients without freezing of gait and 14 controls), stood on a sensorized mat and were asked to take a step forward in response to a pleasant image and a step backward in response to an unpleasant one (congruent task, low cognitive load) or to take a step backward in response to a pleasant image and a step forward in response to an unpleasant one (incongruent task, high cognitive load). Reaction time, step size, anticipatory postural adjustments, and sway path were measured.

RESULTS

In PD with freezing of gait, the reaction time was longer and the step size was shorter than in the other groups when they took a step forward in response to an unpleasant image (incongruent task). Changes in reaction time performance in response to unpleasant images remained significant after having adjusted for executive dysfunction and positively correlated with the "frequency" of freezing episodes.

CONCLUSIONS

This study demonstrates that gait initiation was influenced by the emotional valence of visual stimuli in addition to the cognitive load of the task suggesting that the limbic system may be involved in freezing of gait. © 2018 International Parkinson and Movement Disorder Society.

Wearable sensors objectively measure gait parameters in Parkinson's disease

Distinct gait characteristics like short steps and shuffling gait are prototypical signs commonly observed in Parkinson's disease. Routinely assessed by observation through clinicians, gait is rated as part of categorical clinical scores. There is an increasing need to provide quantitative measurements of gait, e.g. to provide detailed information about disease progression. Recently, we developed a wearable sensor-based gait analysis system as diagnostic tool that objectively assesses gait parameter in Parkinson's disease without the need of having a specialized gait laboratory. This system consists of inertial sensor units attached laterally to both shoes. The computed target of measures are spatiotemporal gait parameters including stride length and time, stance phase time, heel-strike and toe-off angle, toe clearance, and inter-stride variation from gait sequences. To translate this prototype into medical care, we conducted a cross-sectional study including 190 Parkinson's disease patients and 101 age-matched controls and measured gait characteristics during a 4x10 meter walk at the subjects' preferred speed. To determine intraindividual changes in gait, we monitored the gait characteristics of 63 patients longitudinally. Cross-sectional analysis revealed distinct spatiotemporal gait parameter differences reflecting typical Parkinson's disease gait characteristics including short steps, shuffling gait, and postural instability specific for different disease stages and levels of motor impairment. The longitudinal analysis revealed that gait parameters were sensitive to changes by mirroring the progressive nature of Parkinson's disease and corresponded to physician ratings. Taken together, we successfully show that wearable sensor-based gait analysis reaches clinical applicability providing a high biomechanical resolution for gait impairment in Parkinson's disease. These data demonstrate the feasibility and applicability of objective wearable sensor-based gait measurement in Parkinson's disease reaching high technological readiness levels for both, large scale clinical studies and individual patient care.

Benchmarking Foot Trajectory Estimation Methods for Mobile Gait Analysis

Mobile gait analysis systems based on inertial sensing on the shoe are applied in a wide range of applications. Especially for medical applications, they can give new insights into motor impairment in, e.g., neurodegenerative disease and help objectify patient assessment. One key component in these systems is the reconstruction of the foot trajectories from inertial data. In literature, various methods for this task have been proposed. However, performance is evaluated on a variety of datasets due to the lack of large, generally accepted benchmark datasets. This hinders a fair comparison of methods. In this work, we implement three orientation estimation and three double integration schemes for use in a foot trajectory estimation pipeline. All methods are drawn from literature and evaluated against a marker-based motion capture reference. We provide a fair comparison on the same dataset consisting of 735 strides from 16 healthy subjects. As a result, the implemented methods are ranked and we identify the most suitable processing pipeline for foot trajectory estimation in the context of mobile gait analysis.

Short-Term and Long-Term Effects of an Exercise-Based Patient Education Programme in People with Multiple Sclerosis: A Pilot Study

Background. Although people with Multiple Sclerosis (pwMS) benefit from physical exercise, they still show reduced physical activity and exercise behaviour. This study aimed to investigate short- and long-term effects of an exercise-based patient education programme (ePEP) that focuses on empowering pwMS to a sustainable and self-regulated exercise training management. Methods. Fourteen pwMS were randomly assigned to immediate experimental group (EG-I: n = 8) and waitlist-control group (EG-W: n = 6) and attended biweekly in a six-week ePEP. All participants were measured for walking ability, quality of life, fatigue, and self-efficacy towards physical exercise before and after the ePEP, after 12 weeks, and one year after baseline. Short-term effects were analysed in a randomised control trial and long-term effects of all ePEP participants (EG-I + EG-W = EG-all) in a quasi-experimental design. Results. Only functional gait significantly improved in EG-I compared to EG-W (p = 0.008, r = −0.67). Moderate to large effects were found in EG-all for walking ability. Not significant, however, relevant changes were detected for quality of life and fatigue. Self-efficacy showed no changes. Conclusion. The ePEP seems to be a feasible option to empower pwMS to a self-regulated and sustainable exercise training management shown in long-term walking improvements.

Integration of technology-based outcome measures in clinical trials of Parkinson and other neurodegenerative diseases

INTRODUCTION

We sought to review the landscape of past, present, and future use of technology-based outcome measures (TOMs) in clinical trials of neurodegenerative disorders.

METHODS

We systematically reviewed PubMed and ClinicalTrials.gov for published and ongoing clinical trials in neurodegenerative disorders employing TOMs. In addition, medical directors of selected pharmaceutical companies were surveyed on their companies' ongoing efforts and future plans to integrate TOMs in clinical trials as primary, secondary, or exploratory endpoints.

RESULTS

We identified 164 published clinical trials indexed in PubMed that used TOMs as outcome measures in Parkinson disease (n = 132) or other neurodegenerative disorders (n = 32). The ClinicalTrials.gov search yielded 42 clinical trials using TOMs, representing 2.7% of ongoing trials. Sensor-based technology accounted for over 75% of TOMs applied. Gait and physical activity were the most common targeted domains. Within the next 5 years, 83% of surveyed pharmaceutical companies engaged in neurodegenerative disorders plan to deploy TOMs in clinical trials.

CONCLUSION

Although promising, TOMs are underutilized in clinical trials of neurodegenerative disorders. Validating relevant endpoints, standardizing measures and procedures, establishing a single platform for integration of data and algorithms from different devices, and facilitating regulatory approvals should advance TOMs integration into clinical trials.

Immediate effect of subliminal priming with positive reward stimuli on standing balance in healthy individuals: A randomized controlled trial

BACKGROUND

Information received subconsciously can influence exercise performance; however, it remains unclear whether subliminal or supraliminal reward is more effective in improving standing balance ability when priming stimuli are subconsciously delivered. The present study aimed to compare the effects of subliminal priming-plus-subliminal reward stimuli (experimental) with subliminal priming-plus-supraliminal reward stimuli (control) on standing balance ability.

METHODS

This was a single-blind (outcome assessor), parallel-group, randomized controlled trial involving healthy young adults recruited from a university in Japan. Assessments were conducted at baseline and immediately after intervention. The primary outcome was the functional reach test (FRT) measurement. The secondary outcome was one-leg standing time (OLST) with eyes closed. Of the 52 participants screened, 25 were randomly assigned to experimental and control groups each.

RESULTS

Both interventions were effective for improving the FRT between the baseline and intervention; however, smaller improvements were observed in the experimental group. We found a large between-groups effect size immediately after the intervention for the FRT (d = -0.92). In contrast, there were no differences in improvements in OLST between the 2 groups (d = -0.06); furthermore, neither intervention was found to be effective for this parameter.

CONCLUSION

We concluded that subliminal priming with conscious reward stimuli results in improvements in immediate-term forward reach ability, which is superior to that achieved by subliminal priming with subconscious reward stimuli.

No relevant association of kinematic gait parameters with Health-related Quality of Life in Parkinson's disease

BACKGROUND

Health-related Quality of Life (HrQoL) is probably the most important outcome parameter for the evaluation and management of chronic diseases. As this parameter is subjective and prone to bias, there is an urgent need to identify objective surrogate markers. Gait velocity has been shown to be associated with HrQoL in numerous chronic diseases, such as Parkinson's disease (PD). With the development and wide availability of simple-to-use wearable sensors and sophisticated gait algorithms, kinematic gait parameters may soon be implemented in clinical routine management. However, the association of such kinematic gait parameters with HrQoL in PD has not been assessed to date.

METHODS

Kinematic gait parameters from a 20-meter walk from 43 PD patients were extracted using a validated wearable sensor system. They were compared with the Visual Analogue Scale of the Euro-Qol-5D (EQ-5D VAS) by performing a multiple regression analysis, with the International Classification of Functioning, Disability and Health (ICF) model as a framework.

RESULTS

Use of assistive gait equipment, but no kinematic gait parameter, was significantly associated with HrQoL.

CONCLUSION

The widely accepted concept of a positive association between gait velocity and HrQoL may, at least in PD, be driven by relatively independent parameters, such as assistive gait equipment.

Mobile Stride Length Estimation With Deep Convolutional Neural Networks

OBJECTIVE

Accurate estimation of spatial gait characteristics is critical to assess motor impairments resulting from neurological or musculoskeletal disease. Currently, however, methodological constraints limit clinical applicability of state-of-the-art double integration approaches to gait patterns with a clear zero-velocity phase.

METHODS

We describe a novel approach to stride length estimation that uses deep convolutional neural networks to map stride-specific inertial sensor data to the resulting stride length. The model is trained on a publicly available and clinically relevant benchmark dataset consisting of 1220 strides from 101 geriatric patients. Evaluation is done in a tenfold cross validation and for three different stride definitions.

RESULTS

Even though best results are achieved with strides defined from midstance to midstance with average accuracy and precision of , performance does not strongly depend on stride definition. The achieved precision outperforms state-of-the-art methods evaluated on the same benchmark dataset by .

CONCLUSION

Due to the independence of stride definition, the proposed method is not subject to the methodological constrains that limit applicability of state-of-the-art double integration methods. Furthermore, it was possible to improve precision on the benchmark dataset.

SIGNIFICANCE

With more precise mobile stride length estimation, new insights to the progression of neurological disease or early indications might be gained. Due to the independence of stride definition, previously uncharted diseases in terms of mobile gait analysis can now be investigated by retraining and applying the proposed method.

The association between fear of falling and quality of life for balance impairments based on hip and ankle strategies in the drug On- and Off-phase of patients with idiopathic Parkinson' disease

Background: Despite the negative effect of fear of falling during functioning and social participation of patients with Parkinson' disease, so far, only few studies have investigated its effect on the quality of life in these patients. We aimed to investigate the association between fear of falling and quality of life controlling for balance impairments based on hip and ankle strategy in drug On- and Off-phase of patients with idiopathic Parkinson' disease. Methods: In this non-experimental cross-sectional study, 139 patients with idiopathic Parkinson' disease (100 male, 39 female) by mean± SD age of 60.2±12.27 years, mean±SD time since diagnosis of 6.7±5.53 years and mean±SD Hoehn and Yahr stage of 2.8±1.49 were selected by a simple non-probability method. Balance function was measured by a functional reach test with hip and ankle strategy. The Persian version of the selfcompleted Fall Efficacy Scale-International and Parkinson's disease quality of life questionnaire was used to evaluate fear of falling and quality of life, respectively. Results: The results showed that the score of all dimensions of quality of life (i.e., mobility, activities of daily living, emotional wellbeing, stigma, social support, cognition, communication and bodily discomfort) were significantly affected by the intensity of fear of falling. Multiple regression analysis indicated a significant association between fear of falling and quality of life in a way that fear of falling explained 11% to 47% and 12% to 43% of variance in drug On-phase, as well as 8% to 45% and 9% to 48% of variance in the drug Off-phase in dimensions of quality of life after controlling for balance function based on hip and ankle strategy, respectively. In the drug On-phase, the strongest association (R=0.85, p<0.001) was found between fear of falling and mobility dimension of quality of life. In the drug Off-phase, the strongest relation was observed between fear of falling and mobility (R=0.82, p<0.001) as well as activities of daily living (R=0.78-0.79, p<0.001) dimensions. Conclusion: This study found that fear of falling affects the quality of life of patients with Parkinson' disease beyond its relationship with balance impairments based on the hip and ankle strategy in both drug On- and Off-phase.

Sensor-Based Gait Parameter Extraction With Deep Convolutional Neural Networks

Measurement of stride-related, biomechanical parameters is the common rationale for objective gait impairment scoring. State-of-the-art double-integration approaches to extract these parameters from inertial sensor data are, however, limited in their clinical applicability due to the underlying assumptions. To overcome this, we present a method to translate the abstract information provided by wearable sensors to context-related expert features based on deep convolutional neural networks. Regarding mobile gait analysis, this enables integration-free and data-driven extraction of a set of eight spatio-temporal stride parameters. To this end, two modeling approaches are compared: a combined network estimating all parameters of interest and an ensemble approach that spawns less complex networks for each parameter individually. The ensemble approach is outperforming the combined modeling in the current application. On a clinically relevant and publicly available benchmark dataset, we estimate stride length, width and medio-lateral change in foot angle up to -0.15 ± 6.09 cm, -0.09 ± 4.22 cm and 0.13 ± 3.78° respectively. Stride, swing and stance time as well as heel and toe contact times are estimated up to ±0.07, ±0.05, ±0.07, ±0.07 and ±0.12 s respectively. This is comparable to and in parts outperforming or defining state of the art. Our results further indicate that the proposed change in the methodology could substitute assumption-driven double-integration methods and enable mobile assessment of spatio-temporal stride parameters in clinically critical situations as, e.g., in the case of spastic gait impairments.

Objective Gait and Balance Impairments Relate to Balance Confidence and Perceived Mobility in People With Parkinson Disease

BACKGROUND

Body-worn, inertial sensors can provide many objective measures of balance and gait. However, the objective measures that best reflect patient perception of mobility disability and clinician assessment of Parkinson disease (PD) are unknown.

OBJECTIVE

The purposes of this study were: (1) to determine which objective measures of balance and gait are most related to patient perception of mobility disability and disease severity in people with PD and (2) to examine the effect of levodopa therapy on these correlates.

DESIGN

This was an experimental correlation study.

METHODS

One hundred four people with idiopathic PD performed 3 trials of the Instrumented Stand and Walk Test (ISAW) in the "on" and "off" medication states. The ISAW consists of quiet standing (30 seconds), gait initiation, straight walking (7 m), and turning (180°), yielding 34 objective measures of mobility from body-worn inertial sensors. Patient perception of mobility disability was assessed with the Activities-specific Balance Confidence (ABC) scale and the mobility subscale of the Parkinson's Disease Questionnaire (PDQ-39). Disease severity was assessed with the Unified Parkinson's Disease Rating Scale, part III (motor UPDRS). Spearman correlations were used to relate objective measures of mobility to patient perception and disease severity.

RESULTS

Turning speed, gait speed, and stride length were most highly correlated to severity of disease and patient perception of mobility disability. The objective measures of mobility in the off-medication state were more indicative of patient perception of mobility disability and balance confidence compared with on-medication state measures.

LIMITATIONS

Causation is an inherent problem of correlation studies.

CONCLUSION

Physical therapists should evaluate mobility in people with PD in the off-medication state because the off-medication state is more related to disease severity and patient perception of mobility disability than the on-medication state mobility. Assessment and treatment of mobility in people with PD should target specific measures (ie, turning, gait speed, and stride length) because these measures best reflect patients' quality of life and balance confidence.

Can Gait Signatures Provide Quantitative Measures for Aiding Clinical Decision-Making? A Systematic Meta-Analysis of Gait Variability Behavior in Patients with Parkinson's Disease

A disturbed, inconsistent walking pattern is a common feature of patients with Parkinson's disease (PwPD). Such extreme variability in both temporal and spatial parameters of gait has been associated with unstable walking and an elevated prevalence of falls. However, despite their ability to discretise healthy from pathological function, normative variability values for key gait parameters are still missing. Furthermore, an understanding of each parameter's response to pathology, as well as the inter-parameter relationships, has received little attention. The aim of this systematic literature review and meta-analysis was therefore to define threshold levels for pathological gait variability as well as to investigate whether all gait parameters are equally perturbed in PwPD. Based on a broader systematic literature search that included 13′195 titles, 34 studies addressed Parkinson's disease, presenting 800 PwPD and 854 healthy subjects. Eight gait parameters were compared, of which six showed increased levels of variability during walking in PwPD. The most commonly reported parameter, coefficient of variation of stride time, revealed an upper threshold of 2.4% to discriminate the two groups. Variability of step width, however, was consistently lower in PwPD compared to healthy subjects, and therefore suggests an explicit sensory motor system control mechanism to prioritize balance during walking. The results provide a clear functional threshold for monitoring treatment efficacy in patients with Parkinson's disease. More importantly, however, quantification of specific functional deficits could well provide a basis for locating the source and extent of the neurological damage, and therefore aid clinical decision-making for individualizing therapies.

Specific Attentional Disorders and Freezing of Gait in Parkinson's Disease

BACKGROUND

Due to its high prevalence in dual-task paradigms, freezing of gait in Parkinson's disease is thought to be associated with dysexecutive syndrome and attentional disorders. However, the role of specific attentional disorders in patients with freezing of gait is still unclear.

OBJECTIVE

Here, we sought to specifically determine which basic attentional modalities are impaired in patients with freezing of gait.

METHODS

Seventy-eight parkinsonian patients performed a computer-controlled reaction-time paradigm designed to measure the different attentional subcomponents, controlled for visuospatial processing and motor participation.

RESULTS

The freezer (n = 42) and non-freezer (n = 36) groups were matched for age, educational level, MMSE and Mattis Dementia Rating Scale. There were no intergroup differences in simple reaction times, whereas choice reaction times were higher in the freezer group than in the non-freezer group for divided attention (p = 0.023).

CONCLUSIONS

At equivalent levels of overall cognitive efficiency, freezer patients showed a greater slowdown than non-freezer patients with a specific impairment in divided attention.

Technology in Parkinson's disease: Challenges and opportunities

The miniaturization, sophistication, proliferation, and accessibility of technologies are enabling the capture of more and previously inaccessible phenomena in Parkinson's disease (PD). However, more information has not translated into a greater understanding of disease complexity to satisfy diagnostic and therapeutic needs. Challenges include noncompatible technology platforms, the need for wide-scale and long-term deployment of sensor technology (among vulnerable elderly patients in particular), and the gap between the "big data" acquired with sensitive measurement technologies and their limited clinical application. Major opportunities could be realized if new technologies are developed as part of open-source and/or open-hardware platforms that enable multichannel data capture sensitive to the broad range of motor and nonmotor problems that characterize PD and are adaptable into self-adjusting, individualized treatment delivery systems. The International Parkinson and Movement Disorders Society Task Force on Technology is entrusted to convene engineers, clinicians, researchers, and patients to promote the development of integrated measurement and closed-loop therapeutic systems with high patient adherence that also serve to (1) encourage the adoption of clinico-pathophysiologic phenotyping and early detection of critical disease milestones, (2) enhance the tailoring of symptomatic therapy, (3) improve subgroup targeting of patients for future testing of disease-modifying treatments, and (4) identify objective biomarkers to improve the longitudinal tracking of impairments in clinical care and research. This article summarizes the work carried out by the task force toward identifying challenges and opportunities in the development of technologies with potential for improving the clinical management and the quality of life of individuals with PD. © 2016 International Parkinson and Movement Disorder Society.

Quantitative Timed-Up-and-Go Parameters in Relation to Cognitive Parameters and Health-Related Quality of Life in Mild-to-Moderate Parkinson's Disease

Introduction

The instrumented-Timed-Up-and-Go test (iTUG) provides detailed information about the following movement patterns: sit-to-walk (siwa), straight walking, turning and walk-to-sit (wasi). We were interested in the relative contributions of respective iTUG sub-phases to specific clinical deficits most relevant for daily life in Parkinson’s disease (PD). More specifically, we investigated which condition–fast speed (FS) or convenient speed (CS)–differentiates best between mild- to moderate-stage PD patients and controls, which parameters of the iTUG sub-phases are significantly different between PD patients and controls, and how the iTUG parameters associate with cognitive parameters (with particular focus on cognitive flexibility and working memory) and Health-Related-Quality of Life (HRQoL).

Methods

Twenty-eight PD participants (65.1±7.1 years, H&Y stage 1–3, medication OFF state) and 20 controls (66.1±7.5 years) performed an iTUG (DynaPort^®, McRoberts BV, The Netherlands) under CS and FS conditions. The PD Questionnaire 39 (PDQ-39) was employed to assess HRQoL. General cognitive and executive functions were assessed using the Montreal Cognitive Assessment and the Trail Making Test.

Results

The total iTUG duration and sub-phases durations under FS condition differentiated PD patients slightly better from controls, compared to the CS condition. The following sub-phases were responsible for the observed longer total duration PD patients needed to perform the iTUG: siwa, turn and wasi. None of the iTUG parameters correlated relevantly with general cognitive function. Turning duration and wasi maximum flexion velocity correlated strongest with executive function. Walking back duration correlated strongest with HRQoL.

Discussion

This study confirms that mild- to moderate-stage PD patients need more time to perform the iTUG than controls, and adds the following aspects to current literature: FS may be more powerful than CS to delineate subtle movement deficits in mild- to moderate-stage PD patients; correlation levels of intra-individual siwa and wasi parameters may be interesting surrogate markers for the level of automaticity of performed movements; and sub-phases and kinematic parameters of the iTUG may have the potential to reflect executive functioning and HRQoL aspects of PD patients.

The Functional Gait Assessment in Older Adults: Validation Through Rasch Modeling

BACKGROUND

The Functional Gait Assessment (FGA), a measure of walking balance ability, was developed to eliminate the ceiling effect observed in the Dynamic Gait Index (DGI). Three presumably more difficult tasks were added and 1 easier task was removed from the original 8 DGI tasks. The effects of these modifications on item hierarchy have not previously been analyzed.

OBJECTIVE

The purpose of this study was to determine: (1) the ordering of the 10 FGA tasks and the extent to which they map along a clinically logical difficulty continuum, (2) whether the spread of tasks is sufficient to measure patients of varying functional ability levels without a ceiling effect, (3) where the 3 added tasks locate along the task difficulty continuum, and (4) the psychometric properties of the individual FGA tasks.

DESIGN

A retrospective chart review was conducted.

METHODS

Functional Gait Assessment scores from 179 older adults referred for physical therapy for balance retraining were analyzed by Rasch modeling.

RESULTS

The FGA task hierarchy met clinical expectations, with the exception of the "walking on level" task, which locates in the middle of the difficulty continuum. There was no ceiling effect. Two of the 3 added tasks were the most difficult FGA tasks. Performance on the most difficult task ("gait with narrow base of support") demonstrated greater variability than predicted by the Rasch model.

LIMITATIONS

The sample was limited to older adults who were community dwelling and independently ambulating. Findings cannot be generalized to other patient groups.

CONCLUSIONS

The revised scoring criteria of the FGA may have affected item hierarchy. The results suggest that the FGA is a measure of walking balance ability in older adults that is clinically appropriate and has construct validity. Administration of the FGA may be modified further to improve administration efficiency.

A Smartphone-Based Tool for Assessing Parkinsonian Hand Tremor

The aim of this study is to propose a practical smartphone-based tool to accurately assess upper limb tremor in Parkinson's disease (PD) patients. The tool uses signals from the phone's accelerometer and gyroscope (as the phone is held or mounted on a subject's hand) to compute a set of metrics which can be used to quantify a patient's tremor symptoms. In a small-scale clinical study with 25 PD patients and 20 age-matched healthy volunteers, we combined our metrics with machine learning techniques to correctly classify 82% of the patients and 90% of the healthy volunteers, which is high compared to similar studies. The proposed method could be effective in assisting physicians in the clinic, or to remotely evaluate the patient's condition and communicate the results to the physician. Our tool is low cost, platform independent, noninvasive, and requires no expertise to use. It is also well matched to the standard clinical examination for PD and can keep the patient "connected" to his physician on a daily basis. Finally, it can facilitate the creation of anonymous profiles for PD patients, aiding further research on the effectiveness of medication or other overlooked aspects of patients' lives.

Motor cortical oscillations are abnormally suppressed during repetitive movement in patients with Parkinson's disease

OBJECTIVE

Impaired repetitive movement in persons with Parkinson's disease (PD) is associated with reduced amplitude, paradoxical hastening and hesitations or arrest at higher movement rates. This study examined the effects of movement rate and medication on movement-related cortical oscillations in persons with PD.

METHODS

Nine participants with PD were studied off and on medication and compared to nine control participants. Participants performed index finger movements cued by tones from 1 to 3 Hz. Movement-related oscillations were derived from electroencephalographic recordings over the region of the contralateral sensorimotor cortex (S1/M1) during rest, listening, or synchronized movement.

RESULTS

At rest, spectral power recorded over the region of the contralateral S1/M1 was increased in the alpha band and decreased in the beta band in participants with PD relative to controls. During movement, the level of alpha and beta band power relative to baseline was significantly reduced in the PD group, off and on medication, compared to controls. Reduced movement amplitude and hastening at movement rates near 2 Hz was associated with abnormally suppressed and persistent desynchronization of oscillations in alpha and beta bands.

CONCLUSION

Motor cortical oscillations in the alpha and beta bands are abnormally suppressed in PD, particularly during higher rate movements.

SIGNIFICANCE

These findings contribute to the understanding of mechanisms underlying impaired repetitive movement in PD.

How Should Pushing Off or the Use of Assistive Devices Be Incorporated in the Timed Up and Go for Persons With Parkinson Disease?

OBJECTIVES

To determine (1) the relationship between assisted timed Up and Go (TUG) performance and the Parkinson's Disease Questionnaire-39 (PDQ-39), and (2) whether adjusting the TUG score (adding time) improves the relationship between TUG performance and the PDQ-39 in persons with Parkinson disease (PD) who use assistive devices or push off, or both.

DESIGN

Cross-sectional.

SETTING

Twenty participating National Parkinson Foundation Centers of Excellence.

PARTICIPANTS

Data were obtained from participants (N=6624) without exclusion at the 20 participating sites.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The relationship between TUG scores and PDQ-39 mobility scores was determined using the method of linear least squares. Adjusted scores were determined through minimizing the sum of the squared error.

RESULTS

The correlation between assisted TUG scores and PDQ-39 mobility scores was slightly lower (R(2)=.384) compared with the correlation between nonassisted TUG scores and PDQ-39 mobility scores (R(2)=.409). Adjusting assisted TUG performance scores for push off and for use of an assistive device resulted in a modest increase in correlation (R(2)=.399).

CONCLUSIONS

Applying adjustments to assisted TUG may provide clinically important information for evaluating balance, mobility, and falls, and for determining the most effective therapeutic strategies for persons with PD.

Walking adaptability after a stroke and its assessment in clinical settings

Control of walking has been described by a tripartite model consisting of stepping, equilibrium, and adaptability. This review focuses on walking adaptability, which is defined as the ability to modify walking to meet task goals and environmental demands. Walking adaptability is crucial to safe ambulation in the home and community environments and is often severely compromised after a stroke. Yet quantification of walking adaptability after stroke has received relatively little attention in the clinical setting. The objectives of this review were to examine the conceptual challenges for clinical measurement of walking adaptability and summarize the current state of clinical assessment for walking adaptability. We created nine domains of walking adaptability from dimensions of community mobility to address the conceptual challenges in measurement and reviewed performance-based clinical assessments of walking to determine if the assessments measure walking adaptability in these domains. Our literature review suggests the lack of a comprehensive well-tested clinical assessment tool for measuring walking adaptability. Accordingly, recommendations for the development of a comprehensive clinical assessment of walking adaptability after stroke have been presented. Such a clinical assessment will be essential for gauging recovery of walking adaptability with rehabilitation and for motivating novel strategies to enhance recovery of walking adaptability after stroke.

Application of LSVT BIG intervention to address gait, balance, bed mobility, and dexterity in people with Parkinson disease: a case series

BACKGROUND AND PURPOSE

Lee Silverman Voice Treatment Big (LSVT BIG) is characterized by intensive exercising of high-amplitude movements to overcome bradykinesia and hypokinesia in patients with Parkinson disease (PD). The aim of the present case series was to explore possible beneficial effects of LSVT BIG training on gait, balance, bed mobility, and dexterity.

CASE DESCRIPTION

Three patients with mild to moderate PD (all male; aged 52, 54, and 70 years; Hoehn & Yahr stages I-III) completed a 4-week LSVT BIG training program (16 individual 1-hour sessions) and an intensive home training program in accordance with the LSVT BIG protocol. Two certified LSVT BIG physical therapists delivered the LSVT BIG training sessions.

OUTCOMES

The outcome measures for gait and balance included the Functional Gait Assessment (FGA), Functional Reach Test (FRT), Timed "Up & Go" Test (TUG), Freezing of Gait Questionnaire (FOGQ), and motor score on part III of the Unified Parkinson's Disease Rating Scale (UPDRS III). Bed mobility was addressed using the Lindop Parkinson's Disease Mobility Assessment (LPA). The Nine-Hole Peg Test (9HPT) was used to measure dexterity. The 3 patients performed better on balance and gait assessments, as indicated by increased scores on the FRT and FGA (all 3 patients) and decreased scores on the TUG, FOGQ, and UPDRS III, of which scores of the FRT and UPDRS III achieved the minimal detectable change. Furthermore, the patients were quicker in tasks related to bed mobility (LPA). The patients' dexterity skills did not improve for their dominant (right) hand (9HPT).

DISCUSSION

This case series suggests that the LSVT BIG may be beneficial for gait, balance, and bed mobility. Future work is needed to ascertain the effectiveness by means of randomized controlled trials.

Neuromuscular complexity during gait is not responsive to medication in persons with Parkinson's disease

The purpose of this study was to investigate the effects of dopaminergic therapy on neuromuscular complexity during gait and on the relationship between neuromuscular complexity and gait speed in persons with Parkinson's disease (PD). Nine persons with PD walked at self-selected speed for 5 min after having withdrawn from dopaminergic medication for at least 12 h and while optimally-medicated. Electromyographic recordings were taken from eight leg muscles bilaterally. Non-negative matrix factorization was applied to reduce the dimensionality of the electromyographic signals into motor modules. We assessed neuromuscular complexity by investigating the number, structure, and timing of the modules. We also investigated the influence of dopaminergic medication on the relationships between neuromuscular complexity and gait speed. Though gait speed increased significantly after medication intake, medication did not affect neuromuscular complexity. Neuromuscular complexity was significantly associated with gait speed only while the participants were medicated. Thus, the supraspinal structures that govern neuromuscular complexity during gait do not appear to be solely dopaminergically-influenced in PD. The lack of dopaminergic influence on neuromuscular complexity may explain why persons with PD exhibit gait slowness even while medicated, and an intervention that restores neuromuscular complexity may result in gait speed improvement in PD.

Emerging therapies for gait disability and balance impairment: promises and pitfalls

Therapeutic management of gait and balance impairment during aging and neurodegeneration has long been a neglected topic. This has changed considerably during recent years, for several reasons: (1) an increasing recognition that gait and balance deficits are among the most relevant determinants of an impaired quality of life and increased mortality for affected individuals; (2) the arrival of new technology, which has allowed for new insights into the anatomy and functional (dis)integrity of gait and balance circuits; and (3) based in part on these improved insights, the development of new, more specific treatment strategies in the field of pharmacotherapy, deep brain surgery, and physiotherapy. The initial experience with these emerging treatments is encouraging, although much work remains to be done. The objective of this narrative review is to discuss several promising developments in the field of gait and balance treatment. We also address several pitfalls that can potentially hinder a fast and efficient continuation of this vital progress. Important issues that should be considered in future research include a clear differentiation between gait and balance as two distinctive targets for treatment and recognition of compensatory mechanisms as a separate target for therapeutic intervention.

Classification of gait disturbances: distinguishing between continuous and episodic changes

The increased awareness of the importance of gait and postural control to quality of life and functional independence has led many research groups to study the pathophysiology, epidemiology, clinical, and therapeutic aspects of these motor functions. In recognition of the increased awareness of the significance of this topic, the Movement Disorders journal is devoting this entire issue to gait and postural control. Leading research groups provide critical reviews of the current knowledge and propose future directions for this evolving field. The intensive work in this area throughout the world has created an urgent need for a unified language. Because gait and postural disturbances are so common, the clinical classification should be clear, straightforward, and simple to use. As an introduction to this special issue, we propose a new clinically based classification scheme that is organized according to the dominant observed disturbance, while taking into account the results of a basic neurological exam. The proposed classification differentiates between continuous and episodic gait disturbances because this subdivision has important ramifications from the functional, prognostic, and mechanistic perspectives. We anticipate that research into gait and postural control will continue to flourish over the next decade as the search for new ways of promoting mobility and independence aims to keep up with the exponentially growing population of aging older adults. Hopefully, this new classification scheme and the articles focusing on gait and postural control in this special issue of the Movement Disorders journal will help to facilitate future investigations in this exciting, rapidly growing area.

Qualidade de vida de sujeitos com doença de Parkinson e seus cuidadores

Introdução A doença de Parkinson (DP) interfere na autonomia e independência do sujeito, afetando sua qualidade de vida (QV). Cuidadores podem ter sua QV comprometida, em função das dificuldades com o cuidado. Objetivo Avaliar e comparar a QV de sujeitos com DP e seus cuidadores e correlacionar a qualidade de vida com as características dos sujeitos. Material e métodos Foram avaliados 10 sujeitos com DP, com idade média de 65,4 anos, e 8 cuidadores, com idade média de 60,6 anos, de ambos os gêneros. Os instrumentos utilizados foram ficha de avaliação, Questionário PDQ-39, Questionário SF-36, UPDRS e Escala de Hoehn e Yahr modificada. Os dados foram analisados por meio de estatística descritiva e coeficiente de correlação de Pearson e Spearman, utilizando nível de significância de α igual a 5%. Resultados A percepção geral sobre a QV foi moderadamente boa tanto para os sujeitos com DP quanto para cuidadores. No entanto, aspectos motores e emocionais influenciam negativamente a QV dos sujeitos com DP. Do contrário, aspectos sociais, mentais e demográficos parecem não exercer influência significativa. Para os cuidadores, fatores emocionais, sociais e físicos, além de características pessoais, estão relacionados com pior percepção sobre sua QV. As características dos sujeitos com DP e aquelas relacionadas ao cuidado não apresentaram correlação significativa com a QV dos cuidadores. Considerações finais Conhecer os principais fatores que interferem na QV ajuda a direcionar estratégias de prevenção, orientação, suporte e tratamento de pessoas com DP e seus cuidadores. A atenção deve ser integral, voltada para um conjunto de aspectos.

Predictors of quality of life in people with Parkinson's disease: evidence for both domain specific and general relationships

PURPOSE

To assess the determinants of health-related quality of life (HrQoL) in people with Parkinson's disease (PD).

METHOD

Eighty-one people with a diagnosis of idiopathic PD took part in a cross-sectional questionnaire-based study. Measures were collected in a community setting and included established determinants of HrQoL (demographic, clinical and cognitive variables) but also included a wide range of mental health variables (depression, anxiety and stress) and, for the first time, positive psychological functioning (optimism and self-esteem). HrQoL was measured by the full version of the Parkinson's Disease Questionnaire (PDQ-39) which includes eight domains of functioning.

RESULTS

Mental health measures (depression, anxiety and stress) were more influential than any other block of determinants and influenced a broader array of HrQoL domains including physical ones. There was some evidence of domain-specific relationships, e.g. between physical determinants and the more physically-oriented HrQoL domains, and between mental health determinants and emotional well-being. However, cognitive ability did not influence the HrQoL domain of cognitive impairment.

CONCLUSIONS

The contribution of a multi-disciplinary approach is crucial given the many variables which affect HrQoL; in particular, significant overall improvements on HrQoL are unlikely if only physical rehabilitation is offered. Rehabilitation is likely to be beneficial in terms of HrQoL only if it is planned and delivered holistically. Implications for Rehabilitation Interventions to improve physical function may have only limited impact on quality of life and might be limited to more physical HrQoL domains. Psychological interventions have the potential to improve quality of life over a wider range of both emotional and physical HrQoL domains. Clinician-measured level of functioning does not necessarily translate into patient-perceived levels of functional ability and relatively small objective decreases in ability can be appraised much more significantly disabling by people with PD.

Short-distance walking speed tests in people with Parkinson disease: reliability, responsiveness, and validity

PURPOSE

The aims of this study were to determine test-retest reliability and responsiveness of short-distance walking speed tests for persons with Parkinson disease (PD). Discriminant and convergent validity of walking speed tests were also examined.

METHODS

Eighty-eight participants with PD (mean age, 66 years) with mild to moderate severity (stages 1-4 on the Hoehn and Yahr Scale) were tested on medications. Measures of activity included the comfortable and fast 10-m walk tests (CWT, FWT), 6-min walk test (6MWT), mini balance evaluations systems test (mini-BEST Test), fear of falling (FoF), and the Activity-Specific Balance Confidence Scale (ABC). The mobility subsection of the PD quality of life-39 (PDQ39-M) served as a participation-based measure.

RESULTS

Test-retest reliability was high for both walking speed measures (CWT, ICC(2,1) = 0.98; FWT, ICC(2,1) = 0.99). Minimal detectable change (MDC(95)) for the CWT and FWT was 0.09 m/s and 0.13 m/s respectively. Participants at Hoehn & Yahr levels 3/4 demonstrated significantly slower walking speed with the CWT and FWT than participants at Hoehn & Yahr levels 1 and 2 (P < .01). The CWT and FWT were both significantly (P ≤ .002) correlated with all activity and participation-based measures.

CONCLUSIONS

Short-distance walking speed tests are clinically useful measures for persons with PD. The CWT and FWT are highly reliable and responsive to change in persons with PD. Short distance walking speed can be used to discriminate differences in gait function between persons with mild and moderate PD severity. The CWT and FWT had moderate to strong associations with other activity and participation based measures demonstrating convergent validity.

Relationship between the MDS-UPDRS domains and the health-related quality of life of Parkinson's disease patients

BACKGROUND AND PURPOSE

The Movement Disorder Society sponsored version of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is a comprehensive instrument for assessing Parkinson's disease (PD). The present study was aimed at determining the relationships between MDS-UPDRS components and health-related quality of life (HRQoL) evaluations in PD patients.

METHODS

An international, multicenter, cross-sectional study was carried out of 435 PD patients assessed with the MDS-UPDRS, Hoehn and Yahr (HY), Clinical Impression Severity for PD, EQ-5D and PD Questionnaire - eight items (PDQ-8). Spearman's rank correlation coefficients, exploratory factor analysis and multiple linear regression models (dependent variables EQ-5D and PDQ-8) were performed.

RESULTS

The participants' age was 66.71 ± 10.32 years (51.5% men). PD duration was 8.52 ± 6.14, and median HY was 2 (range 1-5). The correlation between the EQ-5D index and the MDS-UPDRS ranged from -0.46 (Part IV) to -0.72 (Part II) and for the PDQ-8 index from 0.47 (Part III) to 0.74 (Part II). In multiple regression models with the MDS-UPDRS domains as independent variables, the main determinant for both the EQ-5D index and the PDQ-8 was Part II followed by Part I. After factorial grouping of the cardinal PD manifestations embedded in the MDS-UPDRS Parts III and IV for inclusion into multiple regression models, a factor formed by M-EDL, nM-EDL and fluctuations was the main determinant for both the EQ-5D and PDQ-8 indexes.

CONCLUSIONS

The MDS-UPDRS component most tightly related with the HRQoL measures was a combination of motor and non-motor experiences of daily living.

Novel, high-intensity exercise prescription improves muscle mass, mitochondrial function, and physical capacity in individuals with Parkinson's disease

We conducted, in persons with Parkinson's disease (PD), a thorough assessment of neuromotor function and performance in conjunction with phenotypic analyses of skeletal muscle tissue, and further tested the adaptability of PD muscle to high-intensity exercise training. Fifteen participants with PD (Hoehn and Yahr stage 2-3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. Skeletal muscle adaptations (P < 0.05) to exercise training in PD included myofiber hypertrophy (type I: +14%, type II: +36%), shift to less fatigable myofiber type profile, and increased mitochondrial complex activity in both subsarcolemmal and intermyofibrillar fractions (I: +45-56%, IV: +39-54%). These adaptations were accompanied by a host of functional and clinical improvements (P < 0.05): total body strength (+30-56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (-30%); 6-min walk (+43 m), Parkinson's Disease Quality of Life Scale (PDQ-39, -7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (-5.7 pts) and motor (-2.7 pts); and fatigue severity (-17%). Additionally, PD subjects in the pretraining state were compared with a group of matched, non-PD controls (CON; did not exercise). A combined assessment of muscle tissue phenotype and neuromuscular function revealed a higher distribution and larger cross-sectional area of type I myofibers and greater type II myofiber size heterogeneity in PD vs. CON (P < 0.05). In conclusion, persons with moderately advanced PD adapt to high-intensity exercise training with favorable changes in skeletal muscle at the cellular and subcellular levels that are associated with improvements in motor function, physical capacity, and fatigue perception.

Attention modulates step initiation postural adjustments in Parkinson freezers

BACKGROUND

In view of freezing of gait's circumstances of occurrence in Parkinson's disease, attentional resources appear to be involved in step initiation failure. Anticipatory postural adjustments (APAs) are essential because they allow unloading of the stepping leg and so create the conditions required for progression. Our main objective was to establish whether or not a change in attentional load during step initiation modulates APAs differently in patients with vs. without freezing of gait.

METHODS

Three groups of 15 subjects were recruited: elderly people and parkinsonian patients with or without freezing of gait. Attention was modulated before step execution by means of an auditory oddball discrimination task with event-related potential recording. The primary endpoint was the occurrence of inappropriate APAs following the attentional task, i.e. APAs not followed by a step after an intercurrent auditory stimulus.

RESULTS

In parkinsonian patients with freezing of gait, inappropriate APAs were recorded in 63% of the trials and were observed more frequently than in patients without freezing of gait (51%) and elderly controls (48%). Furthermore, inappropriate APAs in freezers were longer and more ample than in parkinsonian non-freezers and controls. Lastly, postural preparation was impaired in the parkinsonian patients.

CONCLUSION

Our results indicate that allocation of attentional resources during step preparation influences the release of APAs differently in freezers and non-freezers. Modulating attentional load is partly responsible for triggering an inappropriate motor program. This difficulty in focusing attention or resisting interference may contribute (at least in part) to the gait initiation failure observed in parkinsonian freezers.

Timed up and go, cognitive, and quality-of-life correlates in Parkinson's disease

OBJECTIVE

To examine the relationship between Timed Up and Go (TUG) performance, verbal executive function (EF) performance, and quality-of-life (QOL) measures in Parkinson's disease (PD).

DESIGN

Cross-sectional.

SETTING

Sixteen movement disorder centers from across the United States.

PARTICIPANTS

Patients with PD (N=1964).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

TUG test, immediate and delayed 5-word recall, verbal fluency, PD QOL Questionnaire.

RESULTS

TUG performance and verbal EF performance were significantly associated with, and predictors of, QOL measures, having the greatest association and predictability with the mobility domain of the QOL measures.

CONCLUSIONS

The TUG test and verbal EF tests have QOL correlates, making the combined evaluation of mobility, cognitive, and QOL decline a potential examination tool to evaluate the sequelae of PD.

Quantitative wearable sensors for objective assessment of Parkinson's disease

There is a rapidly growing interest in the quantitative assessment of Parkinson's disease (PD)-associated signs and disability using wearable technology. Both persons with PD and their clinicians see advantages in such developments. Specifically, quantitative assessments using wearable technology may allow for continuous, unobtrusive, objective, and ecologically valid data collection. Also, this approach may improve patient-doctor interaction, influence therapeutic decisions, and ultimately ameliorate patients' global health status. In addition, such measures have the potential to be used as outcome parameters in clinical trials, allowing for frequent assessments; eg, in the home setting. This review discusses promising wearable technology, addresses which parameters should be prioritized in such assessment strategies, and reports about studies that have already investigated daily life issues in PD using this new technology.

Which Aspects of Postural Control Differentiate between Patients with Parkinson's Disease with and without Freezing of Gait?

This exploratory study aimed to identify which aspects of postural control are able to distinguish between subgroups of patients with Parkinson's disease (PD) and controls. Balance was tested using static and dynamic posturography. Freezers (n = 9), nonfreezers (n = 10), and controls (n = 10) stood on a movable force platform and performed 3 randomly assigned tests: (1) sensory organization test (SOT) to evaluate the effective use of sensory information, (2) motor control test (MCT) to assess automatic postural reactions in response to platform perturbations, and (3) rhythmic weight shift test (RWS) to evaluate the ability to voluntarily move the center of gravity (COG) mediolaterally and anterior-posteriorly (AP). The respective outcome measures were equilibrium and postural strategy scores, response strength and amplitude of weight shift. Patients were in the “on” phase of the medication cycle. In general, freezers performed similarly on SOT and MCT compared to nonfreezers. Freezers showed an intact postural strategy during sensory manipulations and an appropriate response to external perturbations. However, during voluntary weight shifting, freezers showed poorer directional control compared to nonfreezers and controls. This suggests that freezers have adequate automatic postural control and sensory integration abilities in quiet stance, but show specific directional control deficits when weight shifting is voluntary.

Feasibility of a virtual exercise coach to promote walking in community-dwelling persons with Parkinson disease

OBJECTIVE

The short-term benefits of exercise for persons with Parkinson disease (PD) are well established, but long-term adherence is limited. The aim of this study was to explore the feasibility, acceptability, and preliminary evidence of the effectiveness of a virtual exercise coach to promote daily walking in community-dwelling persons with Parkinson disease.

DESIGN

Twenty subjects with Parkinson disease participated in this phase 1, single-group, nonrandomized clinical trial. The subjects were instructed to interact with the virtual exercise coach for 5 mins, wear a pedometer, and walk daily for 1 mo. Retention rate, satisfaction, and interaction history were assessed at 1 mo. Six-minute walk and gait speed were assessed at baseline and after the intervention.

RESULTS

Fifty-five percent of the participants were women, and the mean age was 65.6 yrs. At the study completion, there was 100% retention rate. The subjects had a mean satisfaction score of 5.6/7 (with 7 indicating maximal satisfaction) with the virtual exercise coach. Interaction history revealed that the participants logged in for a mean (SD) of 25.4 (7) days of the recommended 30 days. The mean adherence to daily walking was 85%. Both gait speed and the 6-min walk test significantly improved (P < 0.05). No adverse events were reported.

CONCLUSIONS

Sedentary persons with Parkinson disease successfully used a computer and interacted with a virtual exercise coach. Retention, satisfaction, and adherence to daily walking were high for 1 mo, and significant improvements were seen in mobility.

Conceptualizing how group singing may enhance quality of life with Parkinson's disease

Abstract Purpose: Group singing could be a promising component of neurorehabilitative care. This article aims to conceptualize how group singing may enable people with Parkinson's disease (PD) to synchronize their movement patterns to musical rhythm and enhance quality of life.

METHOD

Spanning the medical and social sciences, the article draws conceptually on literature on PD, group singing and rhythm in music; personal experience; and reasoning.

RESULTS

Conceptualizing PD in terms of disruptions to social and biological rhythms, we hypothesize how group singing may produce two socio-psychological states - connectedness and flow - that may entrain rhythm in people with PD. The states connect during group singing to elicit and enhance motor processes but may also reawaken after the group singing, through the recall and reactivation of the musical rhythms encoded during group singing.

CONCLUSIONS

In people with PD, this continuity of flow is hypothesized to be conducive to rhythmic entrainment during and after group singing and in turn to reduced deficits in motor timing and emotional processing, and improvements in quality of life. Empirical studies are needed to test this hypothesis in people with movement disorders such as PD. Implications for Rehabilitation Musical rhythm in group singing may enhance quality of life, and rehabilitation, in people with PD. Use group singing to produce two socio-psychological states - connectedness and flow - that may yield these health benefits. Include people with PD in singing groups to facilitate perceptual exposure to familiar music with melodic distinctiveness and a regular beat.

Unbiased and mobile gait analysis detects motor impairment in Parkinson's disease

Motor impairments are the prerequisite for the diagnosis in Parkinson's disease (PD). The cardinal symptoms (bradykinesia, rigor, tremor, and postural instability) are used for disease staging and assessment of progression. They serve as primary outcome measures for clinical studies aiming at symptomatic and disease modifying interventions. One major caveat of clinical scores such as the Unified Parkinson Disease Rating Scale (UPDRS) or Hoehn&Yahr (H&Y) staging is its rater and time-of-assessment dependency. Thus, we aimed to objectively and automatically classify specific stages and motor signs in PD using a mobile, biosensor based Embedded Gait Analysis using Intelligent Technology (eGaIT). eGaIT consist of accelerometers and gyroscopes attached to shoes that record motion signals during standardized gait and leg function. From sensor signals 694 features were calculated and pattern recognition algorithms were applied to classify PD, H&Y stages, and motor signs correlating to the UPDRS-III motor score in a training cohort of 50 PD patients and 42 age matched controls. Classification results were confirmed in a second independent validation cohort (42 patients, 39 controls). eGaIT was able to successfully distinguish PD patients from controls with an overall classification rate of 81%. Classification accuracy increased with higher levels of motor impairment (91% for more severely affected patients) or more advanced stages of PD (91% for H&Y III patients compared to controls), supporting the PD-specific type of analysis by eGaIT. In addition, eGaIT was able to classify different H&Y stages, or different levels of motor impairment (UPDRS-III). In conclusion, eGaIT as an unbiased, mobile, and automated assessment tool is able to identify PD patients and characterize their motor impairment. It may serve as a complementary mean for the daily clinical workup and support therapeutic decisions throughout the course of the disease.

Using mobile phones for activity recognition in Parkinson's patients

Mobile phones with built-in accelerometers promise a convenient, objective way to quantify everyday movements and classify those movements into activities. Using accelerometer data we estimate the following activities of 18 healthy subjects and eight patients with Parkinson’s disease: walking, standing, sitting, holding, or not wearing the phone. We use standard machine learning classifiers (support vector machines, regularized logistic regression) to automatically select, weigh, and combine a large set of standard features for time series analysis. Using cross validation across all samples we are able to correctly identify 96.1% of the activities of healthy subjects and 92.2% of the activities of Parkinson’s patients. However, when applying the classification parameters derived from the set of healthy subjects to Parkinson’s patients, the percent correct lowers to 60.3%, due to different characteristics of movement. For a fairer comparison across populations we also applied subject-wise cross validation, identifying healthy subject activities with 86.0% accuracy and 75.1% accuracy for patients. We discuss the key differences between these populations, and why algorithms designed for and trained with healthy subject data are not reliable for activity recognition in populations with motor disabilities.

Determinants of health-related quality of life in people with Parkinson's disease: a path analysis

PURPOSE

To identify the demographic factors, impairments and activity limitations that contribute to health-related quality of life (HRQOL) in people with idiopathic Parkinson's disease (PD).

METHOD

Two hundred and ten individuals with idiopathic PD who participated in the baseline assessment of a randomized clinical trial were included. The Parkinson's Disease Questionnaire-39 summary index was used to quantify HRQOL. In order to provide greater clarity regarding the determinants of HRQOL, path analysis was used to explore the relationships between the various predictors in relation to the functioning and disability framework of the International Classification of Functioning model.

RESULTS

The two models of HRQOL that were examined in this study had a reasonable fit with the data. Activity limitations were found to be the strongest predictor of HRQOL. Limitations in performing self-care activities contributed the most to HRQOL in Model 1 (β = 0.38; p < 0.05), while limitations in functional mobility had the largest contribution in Model 2 (β = -0.31; p < 0.0005). Self-reported history of falls was also found to have a significant and direct relationship with HRQOL in both models (Model 1 β = -0.11; p < 0.05; Model 2 β = -0.21; p < 0.05).

CONCLUSIONS

Health-related quality of life in PD is associated with self-care limitations, mobility limitations, self-reported history of falls and disease duration. Understanding how these factors are inter-related may assist clinicians focus their assessments and develop strategies that aim to minimize the negative functional and social sequelae of this debilitating disease.

Capturing ambulatory activity decline in Parkinson's disease

BACKGROUND AND PURPOSE

Relatively little is known about the natural evolution of physical activity-related participation restrictions associated with Parkinson's disease (PD). We examined this issue prospectively, using continuous monitoring technology to capture the free-living ambulatory activity of persons with PD engaging in life situations. We specifically sought (1) to explore natural, long-term changes in daily ambulatory activity and (2) to compare the responsiveness of ambulatory activity parameters to clinical measures of gait and disease severity.

METHODS

Thirty-three persons with PD participated (Hoehn and Yahr range of 1-3). Participants wore a step activity monitor for up to 7 days at baseline and again at 1-year follow-up. Mean daily values were calculated for parameters indicative of amount, intensity, frequency, and duration of ambulatory activity. Clinical measures included the Unified Parkinson Disease Rating Scale, the 6-Minute Walk, and Maximal Gait Speed. Parametric tests for paired samples were used to investigate changes in ambulatory activity parameters and clinical measures.

RESULTS

Participants had significant declines in the amount and intensity of daily ambulatory activity but not in its frequency and duration (P < 0.007). Declines occurred in the absence of changes in clinical measures of gait or disease severity. The greatest 1-year decline occurred in the number of daily minutes participants spent engaging in at least moderate-intensity ambulatory activity.

CONCLUSION

Continuous monitoring of ambulatory activity beyond mere step counts may serve as a distinct and important means of quantifying declining ambulatory behavior associated with disease progression or improved ambulatory behavior resulting from rehabilitation and medical and/or surgical interventions in persons with PD.

A novel conceptual framework for balance training in Parkinson's disease-study protocol for a randomised controlled trial

Background

There is increasing scientific knowledge about the interaction between physiological (musculoskeletal, neuromuscular, cognitive and sensory) systems and their influence on balance and walking impairments in Parkinson’s disease. We have developed a new conceptual framework for balance training, emphasising specific components of balance control related to Parkinson’s disease symptoms by using highly challenging, progressive and varying training conditions. The primary aim of this proposed randomised controlled trial will be to investigate the short-term and long-term effects of a 10-week balance training regime in elderly with Parkinson’s disease.

Methods/Design

Eighty participants with mild to moderate idiopathic Parkinson’s disease will be recruited and randomly allocated to an intervention group receiving balance training or a control group whose participants will continue to receive their usual care. The intervention will consist of a 10-week group training regime (1-hour training, three times per week), which will be led by two physiotherapists to ensure training progression and safety. The conceptual framework will be applied by addressing specific balance components (sensory integration, anticipatory postural adjustments, motor agility, stability limits) through varying training conditions and structured progression. Assessment will be conducted through a multi-dimensional battery of outcomes, prior to and immediately after the 10-week intervention, and at 9 and 15 months’ follow-up after entering the study. Primary outcome measures will be balance performance (assessed using the Mini Balance Evaluation Systems Test), change in gait velocity (m/s) between single and dual task walking, and fear of falling (evaluated using the Fall Efficacy Scale International).

Discussion

This study has the potential to provide new insight and knowledge of the effects of specific, varied and challenging balance training on a wide health spectrum in elderly with PD. If found to be effective, this pragmatic approach with translation of theory into practice, can be implemented in existing outpatient care.

Trial registration

NCT01417598