Monitoring of walking in Parkinson's disease: validation of an ambulatory activity monitor

Natural Walking Intensity in Persons With Parkinson Disease

BACKGROUND AND PURPOSE

Few persons with Parkinson disease (PD) appear to engage in moderate-intensity walking associated with disease-modifying health benefits. How much time is spent walking at lower, yet still potentially beneficial, intensities is poorly understood. The purpose of this exploratory, observational study was to describe natural walking intensity in ambulatory persons with PD.

METHODS

Accelerometer-derived real-world walking data were collected for more than 7 days at baseline from 82 participants enrolled in a PD clinical trial. Walking intensity was defined according to the number of steps in each active minute (1-19, 20-39, 40-59, 60-79, 80-99, or ≥100 steps). Daily minutes of walking and duration of the longest sustained walking bout were calculated at each intensity. Number of sustained 10 to 19, 20 to 29, and 30-minute bouts and greater at any intensity also were calculated. Values were analyzed in the context of physical activity guidelines.

RESULTS

Most daily walking occurred at lower intensities (157.3 ± 58.1 min of 1-19 steps; 81.3 ± 32.6 min of 20-39 steps; 38.2 ± 21.3 min of 40-59 steps; 15.1 ± 11.5 min of 60-79 steps; 7.4 ± 7.0 min of 80-99 steps; 7.3 ± 9.6 min of ≥100 steps). The longest daily sustained walking bout occurred at the lowest intensity level (15.9 ± 5.2 min of 1-19 steps). Few bouts lasting 20 minutes and greater occurred at any intensity.

DISCUSSION AND CONCLUSIONS

Despite relatively high daily step counts, participants tended to walk at remarkably low intensity, in bouts of generally short duration, with relatively few instances of sustained walking. The findings reinforced the need for health promotion interventions designed specifically to increase walking intensity.Video Abstract available for more insight from authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A426 ).

Feasibility and Proof-of-Concept of Delivering an Autonomous Music-Based Digital Walking Intervention to Persons with Parkinson's Disease in a Naturalistic Setting

BACKGROUND

Reduced motor automaticity in Parkinson's disease (PD) negatively impacts the quality, intensity, and amount of daily walking. Rhythmic auditory stimulation (RAS), a clinical intervention shown to improve walking outcomes, has been limited by barriers associated with the need for ongoing clinician input.

OBJECTIVE

To assess the feasibility, proof-of-concept, and preliminary clinical outcomes associated with delivering an autonomous music-based digital walking intervention based on RAS principles to persons with PD in a naturalistic setting.

METHODS

Twenty-three persons with PD used the digital intervention independently for four weeks to complete five weekly 30-minute sessions of unsupervised, overground walking with music-based cues. The intervention progressed autonomously according to real-time gait sensing. Feasibility of independent use was assessed by examining participant adherence, safety, and experience. Intervention proof-of-concept was assessed by examining spatiotemporal metrics of gait quality, daily minutes of moderate intensity walking, and daily steps. Preliminary clinical outcomes were assessed following intervention completion.

RESULTS

Participants completed 86.4% of sessions and 131.1% of the prescribed session duration. No adverse events were reported. Gait speed, stride length, and cadence increased within sessions, and gait variability decreased (p < 0.05). Compared to baseline, increased daily moderate intensity walking (mean Δ= +21.44 minutes) and steps (mean Δ= +3,484 steps) occurred on designated intervention days (p < 0.05). Quality of life, disease severity, walking endurance, and functional mobility were improved after four weeks (p < 0.05).

CONCLUSIONS

Study findings supported the feasibility and potential clinical utility of delivering an autonomous digital walking intervention to persons with PD in a naturalistic setting.

Improvement in the Capacity for Activity Versus Improvement in Performance of Activity in Daily Life During Outpatient Rehabilitation

We addressed questions about the potential discrepancy between improvements in activity capacity and improvements in activity performance in daily life. We asked whether this discrepancy is: Common in routine, outpatient care, or an artifact of intervention studies? Unique to upper limb (UL) rehabilitation, or is it seen in walking rehabilitation too? Only seen in persons with stroke, or a broader neurorehabilitation problem?

Does clinically measured walking capacity contribute to real-world walking performance in Parkinson's disease?

OBJECTIVE

The study examined how clinically measured walking capacity contributes to real-world walking performance in persons with Parkinson's disease (PD).

METHODS

Cross-sectional baseline data (n = 82) from a PD clinical trial were analyzed. The 6-Minute Walk Test (6MWT) and 10-Meter Walk Test (10MWT) were used to generate capacity metrics of walking endurance and fast gait speed, respectively. An activity monitor worn for seven days was used to generate performance metrics of mean daily steps and weekly moderate intensity walking minutes. Univariate linear regression analyses were used to examine associations between each capacity and performance measure in the full sample and less and more active subgroups.

RESULTS

Walking capacity significantly contributed to daily steps in the full sample (endurance: R2=.13, p < .001; fast gait speed: R2=.07, p = .017) and in the less active subgroup (endurance: R2 =.09, p = .045). Similarly, walking capacity significantly contributed to weekly moderate intensity minutes in the full sample (endurance: R2=.13, p < .001; fast gait speed: R2=.09, p = .007) and less active subgroup (endurance: R2 = .25, p < .001; fast gait speed: R2 =.21, p = .007). Walking capacity did not significantly contribute to daily steps or moderate intensity minutes in the more active subgroup.

CONCLUSIONS

Walking capacity contributed to, but explained a relatively small portion of the variance in, real-world walking performance. The contribution was somewhat greater in less active individuals. The study adds support to the idea that clinically measured walking capacity may have limited benefit for understanding real-world walking performance in PD. Factors beyond walking capacity may better account for actual walking behavior.

Are Mobile Persons With Parkinson Disease Necessarily More Active?

BACKGROUND AND PURPOSE

Walking activity in persons with Parkinson disease (PD) is important for preventing functional decline. The contribution of walking activity to home and community mobility in PD is poorly understood.

METHODS

Cross-sectional baseline data (N = 69) were analyzed from a randomized controlled PD trial. The Life-Space Assessment (LSA) quantified the extent, frequency, and independence across 5 expanding levels of home and community mobility, producing individual subscores and a total score. Two additional summed scores were used to represent mobility within (Levels 1-3) and beyond (Levels 4-5) neighborhood limits. An accelerometer measured walking activity for 7 days. Regression and correlation analyses evaluated relationships between daily steps and mobility scores. Mann-Whitney U tests secondarily compared differences in mobility scores between the active and sedentary groups.

RESULTS

Walking activity contributed significantly to the summed Level 1-3 score (β = 0.001, P = 0.004) but not to the summed Level 4-5 (β = 0.001, P = 0.33) or total (β = 0.002, P = 0.07) scores. Walking activity was significantly related to Level 1 (ρ = 0.336, P = 0.005), Level 2 (ρ = 0.307, P = 0.010), and Level 3 (ρ = 0.314, P = 0.009) subscores. Only the summed Level 1-3 score (P = 0.030) was significantly different between the active and sedentary groups.

DISCUSSION AND CONCLUSIONS

Persons with PD who demonstrated greater mobility beyond the neighborhood were not necessarily more active; walking activity contributed more so to home and neighborhood mobility. Compared with LSA total score, the Level 1-3 summed score may be a more useful participation-level measure for assessing the impact of changes in walking activity.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A349).

Tablet-Based Application for Objective Measurement of Motor Fluctuations in Parkinson Disease

BACKGROUND

The motor subscale of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS-III) has limited applicability for the assessment of motor fluctuations in the home setting.

METHODS

To assess whether a self-administered, tablet-based application can reliably quantify differences in motor performance using two-target finger tapping and forearm pronation-supination tasks in the ON (maximal dopaminergic medication efficacy) and OFF (reemergence of parkinsonian deficits) medication states, we recruited 11 Parkinson disease (PD) patients (age, 60.6 ± 9.0 years; disease duration, 12.8 ± 4.1 years) and 11 healthy age-matched controls (age, 62.5 ± 10.5 years). The total number of taps, tap interval, tap duration, and tap accuracy were algorithmically calculated by the application, using the more affected side in patients and the dominant hand in healthy controls.

RESULTS

Compared to the OFF state, PD patients showed a higher number of taps (84.2 ± 20.3 vs. 54.9 ± 26.9 taps; p = 0.0036) and a shorter tap interval (375.3 ± 97.2 vs. 708.2 ± 412.8 ms; p = 0.0146) but poorer tap accuracy (2,008.4 ± 995.7 vs. 1,111.8 ± 901.3 pixels; p = 0.0055) for the two-target task in the ON state, unaffected by the magnitude of coexistent dyskinesia. Overall, test-retest reliability was high (r >0.75) and the discriminatory ability between OFF and ON states was good (0.60 ≤ AUC ≤ 0.82). The correlations between tapping data and MDS-UPDRS-III scores were only moderate (-0.55 to 0.55).

CONCLUSIONS

A self-administered, tablet-based application can reliably distinguish between OFF and ON states in fluctuating PD patients and may be sensitive to additional motor phenomena, such as accuracy, not captured by the MDS-UPDRS-III.

Physical Activity Monitoring in Patients with Neurological Disorders: A Review of Novel Body-Worn Devices

Aim

The aim was to conduct a systematic review to examine the literature reporting the validity and reliability of wearable physical activity monitoring in individuals with neurological disorders.

Method

A systematic search of the literature was performed using a specific search strategy in PubMed and CINAHL. A search constraint of articles published in English, including human participants, published between January 2008 and March 2017 was applied. Peer-reviewed studies which enrolled adult participants with any neurological disorder were included. For the studies which sought to explore the validity of activity monitors, the outcomes measured using the monitor were compared to a criterion measure of physical activity. The studies' methodological quality was assessed using an adapted version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) framework. Data extracted from each study included the following: characteristics of the study participants, study setting, devices used, study protocol/methods, outcomes measured, and the validity/reliability of measurement produced.

Results

Twenty-three studies examining the validity and reliability of 16 different monitors were included. The identified studies comprised participants with a range of different disorders of neurological origin. The available evidence suggests that biaxial or triaxial accelerometer devices positioned around the ankle produce the most accurate step count measurements in patients with neurological disorders. The findings regarding the reliability and validity of activity counts and energy expenditure are largely inconclusive in this population.

Discussion

Ankle-worn biaxial or triaxial accelerometer-type devices provide the most accurate measurement of physical activity. However, further work is required in this field before wearable activity monitoring can be more widely implemented clinically. Standardised activity monitoring protocols are required for implementing these devices in clinical trials and clinical practice, and consensus is required as to the reporting and interpretation of derived variables.

Auditing the Physical Activity and Parkinson Disease Literature Using the Behavioral Epidemiologic Framework

Motor and nonmotor symptoms associated with Parkinson disease place individuals at greater risk of sedentary behaviors and comorbidities. Physical activity is one modifiable means of improving health and reducing the risk of morbidity. We applied a behavioral framework to classify existing research on physical activity and Parkinson disease to describe the current evolution and inform knowledge gaps in this area. Research placed in phase 1 establishes links between physical activity and health-related outcomes; phase 2 develops approaches to quantify physical activity behavior; phase 3 identifies factors associated with implementation of physical activity behaviors; phase 4 assesses the effectiveness of interventions to promote activity; and phase 5 disseminates evidence-based recommendations. Peer-reviewed literature was identified by searching PubMed, Google Scholar, and EBSCO-host. We initially identified 287 potential articles. After further review, we excluded 109 articles, leaving 178 included articles. Of these, 75.84% were categorized into phase 1 (n = 135), 10.11% in phase 2 (n = 18), 9.55% into phase 3 (n = 17), 3.37% into phase 4 (n = 6), and 1.12% into phase 5 (n = 2). By applying the behavioral framework to the physical activity literature for people with Parkinson disease, we suggest this area of research is nascent with more than 75% of the literature in phase 1.

LEVEL OF EVIDENCE

III.

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.

A Viewpoint on Wearable Technology-Enabled Measurement of Wellbeing and Health-Related Quality of Life in Parkinson's Disease

In this viewpoint, we discuss how several aspects of Parkinson's disease (PD) - known to be correlated with wellbeing and health-related quality of life-could be measured using wearable devices ('wearables'). Moreover, three people with PD (PwP) having exhaustive experience with using such devices write about their personal understanding of wellbeing and health-related quality of life, building a bridge between the true needs defined by PwP and the available methods of data collection. Rapidly evolving new technologies develop wearables that probe function and behaviour in domestic environments of people with chronic conditions such as PD and have the potential to serve their needs. Gathered data can serve to inform patient-driven management changes, enabling greater control by PwP and enhancing likelihood of improvements in wellbeing and health-related quality of life. Data can also be used to quantify wellbeing and health-related quality of life. Additionally these techniques can uncover novel more sensitive and more ecologically valid disease-related endpoints. Active involvement of PwP in data collection and interpretation stands to provide personally and clinically meaningful endpoints and milestones to inform advances in research and relevance of translational efforts in PD.

Home-based system for physical activity monitoring in patients with multiple sclerosis (Pilot study)

Background

Limitations in physical activity are considered as a key problem in patients with multiple sclerosis (PwMS). Contemporary methods to assess the level of physical activity in PwMS are regular clinical observation. However, these methods either rely on high recall and accurate reporting from the patients (e.g. self-report questionnaires), or they are conducted during a particular clinical assessment with predefined activities. Therefore, the main aim of this pilot study was to develop an objective method to gather information about the real type and intensity of daily activities performed by PwMS in every-day living situations using an accelerometer. Furthermore, the accelerometer-derived measures are investigated regarding their potential for discriminating between different MS groups.

Methods

Eleven PwMS that were able to walk independently (EDSS ≤ 5) were divided into two groups: mild disability (EDSS 1–2.5; n = 6) and moderate disability (EDSS 3 –5; n = 5). Participants made use of an activity monitor device attached to their waist during their normal daily activities over 4 measurements. Activity parameters were assessed and compared for the time of each participant’s first measurement and follow-up measurement. Furthermore, differences between both subgroups, and the correlation of activity parameters with the clinical neurological variable (EDSS) were investigated.

Results

Participants showed significant decline in step count (p = 0.008), maximum walking speed (p = 0.02) and physical activity intensity (p = 0.03) throughout the study period. Compared to the mild subgroup, moderate affected participant accumulated less number of steps (G1: 9214.33 ± 2439.11, G2: 5018.13 ± 2416.96; p < 0.005) and were slower (G1: 1.48 ± 0.19, G2: 1.12 ± 0.44; p = 0.03). Additionally, the EDSS correlated negatively with mean walking speed (r = - 0.71, p = 0.01) and steps count (r = - 0.54, p = 0.08).

Conclusions

In this study, we used a portable activity monitoring sensor to gather information about everyday physical activity in PwMS at home. We showed that objective measurements using simple 3D accelerometers can track daily physical activity fluctuation. Furthermore, they track disability changes better than clinical measures. Thus, they can help to develop activity based treatments for PwMS.

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.

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.

Caudate Nucleus Volume Mediates the Link between Cardiorespiratory Fitness and Cognitive Flexibility in Older Adults

The basal ganglia play a central role in regulating the response selection abilities that are critical for mental flexibility. In neocortical areas, higher cardiorespiratory fitness levels are associated with increased gray matter volume, and these volumetric differences mediate enhanced cognitive performance in a variety of tasks. Here we examine whether cardiorespiratory fitness correlates with the volume of the subcortical nuclei that make up the basal ganglia and whether this relationship predicts cognitive flexibility in older adults. Structural MRI was used to determine the volume of the basal ganglia nuclei in a group of older, neurologically healthy individuals (mean age 66 years, N = 179). Measures of cardiorespiratory fitness (VO(2max)), cognitive flexibility (task switching), and attentional control (flanker task) were also collected. Higher fitness levels were correlated with higher accuracy rates in the Task Switching paradigm. In addition, the volume of the caudate nucleus, putamen, and globus pallidus positively correlated with Task Switching accuracy. Nested regression modeling revealed that caudate nucleus volume was a significant mediator of the relationship between cardiorespiratory fitness, and task switching performance. These findings indicate that higher cardiorespiratory fitness predicts better cognitive flexibility in older adults through greater grey matter volume in the dorsal striatum.

Alpha oscillations in the pedunculopontine nucleus correlate with gait performance in parkinsonism

The pedunculopontine nucleus, a component of the reticular formation, is topographically organized in animal models and implicated in locomotor control. In Parkinson's disease, pedunculopontine nucleus stimulation is an emerging treatment for gait freezing. Local field potentials recorded from pedunculopontine nucleus electrodes in such patients have demonstrated oscillations in the alpha and beta frequency bands, reactive to self-paced movement. Whether these oscillations are topographically organized or relevant to locomotion is unknown. Here, we recorded local field potentials from the pedunculopontine nucleus in parkinsonian patients during rest and unconstrained walking. Relative gait speed was assessed with trunk accelerometry. Peaks of alpha power were present at rest and during gait, when they correlated with gait speed. Gait freezing was associated with attenuation of alpha activity. Beta peaks were less consistently observed across rest and gait, and did not correlate with gait speed. Alpha power was maximal in the caudal pedunculopontine nucleus region and beta power was maximal rostrally. These results indicate a topographic distribution of neuronal activity in the pedunculopontine nucleus region and concur with animal data suggesting that the caudal subregion has particular relevance to gait. Alpha synchronization, proposed to suppress 'task irrelevant' distraction, has previously been demonstrated to correlate with performance of cognitive tasks. Here, we demonstrate a correlation between alpha oscillations and improved gait performance. The results raise the possibility that stimulation of caudal and rostral pedunculopontine nucleus regions may differ in their clinical effects.