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Aim: The goal of this study was to analyze the effects of external rhythmic auditory stimulation (RAS) on gait variability in older adults and people with Parkinson's disease (PD). Methods: Academic databases searched included PubMed, Web of Science, PEDro and Cochrane, from inception to September 2021. Eligible articles scored a minimum of 4 on the PEDro scale. Results: Twenty-three papers were included. People with PD show varied responses in gait variability to RAS during cued walking trials. Healthy older adults tended to increase variability during cued trials. Cue rates below preferred walking cadence tend to increase gait variability. Conclusion: Gait variability is closely associated with fall risk and an important consideration in development of gait rehabilitation techniques.

The study examined how clinically measured walking capacity contributes to real-world walking performance in persons with Parkinson's disease (PD).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.Walking capacity significantly contributed to daily steps in the full sample (endurance: RWalking 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.

There has been increasing research on the impact of dance as a therapeutic intervention and alternative exercise for improving physical health and psychosocial outcomes. Prior reviews center on specific populations, such as those living with Parkinson's disease or older adults, but few center on a specific dance style such as classical ballet. This review aims to synthesize the current literature on classical ballet as a therapeutic intervention for novices and analyze its effects on movement outcomes, perceived value, and other health outcomes to inform future research directions. In total, 23 articles were identified using PubMed and Scopus from inception through March 2022; 14 that met the inclusion criteria are discussed in this review. Altogether, the literature is extremely mixed-spanning different populations, intervention protocols, doses, and measurement tools-making comparisons difficult. Overall, classical ballet appears to be a safe and feasible intervention for multiple populations. Engaging in classical ballet may be associated with improvements in balance and postural control and has a high perceived value among participants and instructors, but the evidence is limited and of poor quality. Rigorous research is required to provide stronger, more credible evidence on the potential value of classical ballet as a therapeutic intervention.

Digital therapeutics, treatments delivered remotely and enabled by modern technology, facilitate the provision of personalized, evidence-based, interdisciplinary interventions to manage the complexities associated with Parkinson’s disease. In the context of the COVID-19 pandemic, the need for digital therapeutics has arguably never been greater. However, despite new advances in technology and a heightened interest due to the pandemic, digital therapeutics remain underdeveloped and underutilized. In this paper, we briefly review practical applications and emerging advances in digital therapeutic platforms that target motor and non-motor signs and healthy lifestyle behaviors such as regular exercise, a healthful diet and optimal sleep hygiene habits. Future applications which could transform personalized self-management and patient care are presented. Opportunities, drawbacks and barriers to access are discussed.

Several case studies and anecdotal reports have shown assorted motor and quality of life benefits from use of a dental mouthpiece among people with Parkinson disease (PD). A larger exploratory study is necessary to assess potential efficacy and feasibility of this treatment strategy. If shown to be effective and feasible in a larger sample of people with PD, mechanistic studies may be warranted to examine a potential relationship between orofacial sensory input and motor function in people with PD.This study was registered on clinicaltrials.gov (NCT: 04082663). Twenty people with PD, Hoehn and Yahr stages I-III, participated in this study. Each participant completed various baseline motor and quality of life assessments before being fitted with a custom mouthpiece. Motor assessments were completed a second time after 25 min of mouthpiece wear. Participants were asked to wear the mouthpiece for 1 month before completing follow-up quality of life assessments and providing feedback about the mouthpiece. Wilcoxon signed-rank tests were used to compare results across conditions.Gait velocity and cadence showed significant (These results do not provide adequate evidence to pursue further this type of mouthpiece as a treatment strategy for motor signs and symptoms or quality of life in people with PD.

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).

Background Gait deficits in Parkinson disease (PD), including freezing of gait (FOG), can be among the most debilitating symptoms. Rhythmic auditory cueing has been used to alleviate some gait symptoms. However, different cue types, such as externally-generated and self-generated cues, affect gait variability differently. The differential effects of these cue types on people with PD with FOG (PD + FOG), who often have higher gait variability, and those with PD without FOG (PD-FOG) is unknown. Given the relationship of gait variability to fall risk, this is an important area to address. Research question This study aims to 1) confirm the association between falls and gait variability measures in PD-FOG, PD + FOG and age-matched Controls; 2) investigate the effects of different cue types on gait variability in PD-FOG and PD + FOG; and 3) determine whether baseline gait characteristics are associated with response to cues. Methods This cross-sectional study investigated PD-FOG (n = 24), PD + FOG (n = 20), and Controls (n = 24). Gait trials were collected during use of externally-generated and self-generated cues for all participants. Gait variability measures were the primary outcomes to assess the effects of rhythmic auditory cues. Results Logistic regression models showed increased gait variability was associated with falls across groups. Repeated measures ANOVAs showed externally-generated cues increased gait variability, whereas self-generated cues did not, for all groups. Pearson’s correlations showed participants with higher baseline gait variability had greater reduction in gait variability with rhythmic auditory cueing. Significance Higher gait variability is associated with falls. This study demonstrates that PD + FOG are capable of using self-generated cues without increasing gait variability measures, thereby stabilizing gait. People with higher baseline gait variability are likely to experience the largest reductions in variability with the addition of external cues.

In this paper, we develop an algorithm to automatically validate and segment a gait cycle in real time into three gait events, namely midstance, toe-off, and heel-strike, using inertial sensors. We first use the physical models of sensor data obtained from a foot-mounted inertial system to differentiate stationary and moving segments of the sensor data. Next, we develop an optimization routine called sparsity-assisted wavelet denoising (SAWD), which simultaneously combines linear time invariant filters, orthogonal multiresolution representations such as wavelets, and sparsity-based methods, to generate a sparse template of the moving segments of the gyroscope measurements in the sagittal plane for valid gait cycles. Thereafter, to validate any moving segment as a gait cycle, we compute the root-mean-square error between the generated sparse template and the sparse representation of the moving segment of the gyroscope data in the sagittal plane obtained using SAWD. Finally, we find the local minima for the stationary and moving segments of a valid gait cycle to detect the gait events. We compare our proposed method with existing methods, for a fixed threshold, using real data obtained from three groups, namely controls, participants with Parkinson disease, and geriatric participants. Our proposed method demonstrates an average F1 score of 87.78% across all groups for a fixed sampling rate, and an average F1 score of 92.44% across all Parkinson disease participants for a variable sampling rate.

Background Parkinson disease (PD) is a debilitating and chronic neurodegenerative disease resulting in ambulation difficulties. Natural walking activity often declines early in disease progression despite the relative stability of motor impairments. In this study, we propose a paradigm shift with a “connected behavioral approach” that targets real-world walking using cognitive-behavioral training and mobile health (mHealth) technology. Methods/design The Walking and mHealth to Increase Participation in Parkinson Disease (WHIP-PD) study is a twelve-month, dual site, two-arm, randomized controlled trial recruiting 148 participants with early to mid-stage PD. Participants will be randomly assigned to connected behavioral or active control conditions. Both conditions will include a customized program of goal-oriented walking, walking-enhancing strengthening exercises, and eight in-person visits with a physical therapist. Participants in the connected behavioral condition also will (1) receive cognitive-behavioral training to promote self-efficacy for routine walking behavior and (2) use a mHealth software application to manage their program and communicate remotely with their physical therapist. Active control participants will receive no cognitive-behavioral training and manage their program on paper. Evaluations will occur at baseline, three-, six-, and twelve-months and include walking assessments, self-efficacy questionnaires, and seven days of activity monitoring. Primary outcomes will include the change between baseline and twelve months in overall amount of walking activity (mean number of steps per day) and amount of moderate intensity walking activity (mean number of minutes per day in which > 100 steps were accumulated). Secondary outcomes will include change in walking capacity as measured by the six-minute walk test and ten-meter walk test. We also will examine if self-efficacy mediates change in amount of walking activity and if change in amount of walking activity mediates change in walking capacity. Discussion We expect this study to show the connected behavioral approach will be more effective than the active control condition in increasing the amount and intensity of real-world walking activity and improving walking capacity. Determining effective physical activity interventions for persons with PD is important for preserving mobility and essential for maintaining quality of life. Clinical trials registration NCT03517371, May 7, 2018. Trial registration ClinicalTrials.gov: NCT03517371. Date of registration: May 7, 2018. Protocol version: Original.

People with Parkinson disease demonstrate increased gait variability, but the primary variability sources are poorly understood. People with Parkinson disease and freezing of gait (freezers) have greater gait impairments than people with Parkinson disease without freezing of gait (nonfreezers), which may relate to cerebellar dysfunction. Thirteen freezers and 31 nonfreezers completed backward, forward, and forward with dual task gait trials. Sagittal joint angle waveforms were extracted for the hip, knee, and ankle using 3D motion capture. Decomposition indices were calculated for the 3 joint combinations. Principal component analysis extracted variance sources from the joint waveforms. Freezers had significantly greater decomposition between hip–ankle (F1,42 = 5.1, P = .03) and hip–knee (F1,42 = 5.3, P = .03) movements. The principal component analysis did not differentiate freezers and nonfreezers; however, primary variance sources differed between conditions. Primary variance during forward and forward with dual task gait came from joint angle magnitude and peak angle timing. Backward gait showed primary variance from joint angle magnitude and range of motion. The results show that freezers decompose movement more than nonfreezers, implicating cerebellar involvement in freezing of gait. Primary variance differs between gait conditions, and tailoring gait interventions to address variability sources may improve intervention efficacy.

Background and purpose Alzheimer disease (AD) is the most common form of dementia and the sixth leading cause of death in the United States. Falls are associated with AD and can lead to injury. The Balance Evaluation Systems Test (BESTest) is a balance measure used in other neurological conditions to predict fall risk. The purpose of this study is to examine the relationship between MiniBestest, BESTest, and BESTest subsection scores and fall incidence among individuals with a diagnosis of mild AD. Methods The study was a single centre, prospective, observational cohort study. Participants completed baseline questionnaires including a demographic form, a fall history questionnaire and the Barthel Index of Activities of Daily Living (ADLs). Balance and gait were assessed using the MiniBESTest and BESTest. After completing baseline assessment, participants were given monthly fall calendars to track falls for the next 12 months. Results MiniBESTest total raw score for fallers was 13.4 out of 28 (SD = 3.6) and for non-fallers was 18.4 of out 28 (SD = 3.7). MiniBESTest total percentage score for fallers was 47.8% (SD = 12.8%) and for non-fallers was 65.5% (SD = 13.1%). BESTest total percentage scores for fallers was 58.2% (SD = 3.9%) and for non-fallers was 73.9% (SD = 7.9%). Subsections II-IV of the BESTest correlated with faller status. Discussion and conclusions Among individuals with mild AD, fall status was associated with certain balance deficits on the BESTest including moving body outside base of support (subsection II), changing centre of mass (subsection III), and reacting to external perturbations (subsection IV). Future studies could explore differences between AD and other neurological conditions and how physical therapy could improve these areas to reduce fall risk.

Objective he purpose of the study was to determine the impact of novel coronavirus 2019 (COVID-19) restrictions on community-based exercise classes for people with Parkinson disease (PD) and their instructors. Methods Data were collected via custom-designed electronic surveys for people with PD and class instructors who reported attending or teaching PD-specific exercise class ≥1 time/week for ≥3 months prior to pandemic restrictions (March 2020). The PD group also completed the Godin Leisure-Time Questionnaire, Self-Efficacy for Exercise scale, Schwab-England scale, and Parkinson’s Disease Questionnaire 8. Results Eighty-seven people with PD (mean = 70 [7.3] years old) and 43 instructors (51 [12.1] years old) from the United States completed surveys (October 2020 to February 2021). Mean Schwab-England (84 [16]) and Parkinson’s Disease Questionnaire 8 (21 [15]) scores indicated low-to-moderate disability in the PD group. Ninety-five percent of the PD group had COVID-19 exposure concerns, and 54% reported leaving home ≤1 time/week. Although 77% of the PD group scored “active” on the Godin Leisure-Time Questionnaire, the mean Self-Efficacy for Exercise Scale score (55 [24]) indicated only moderate exercise self-efficacy, and >50% reported decreased exercise quantity/intensity compared with pre-COVID. There was decreased in-person and increased virtual class participation for both groups. The top in-person class barrier for the PD (63%) and instructor (51%) groups was fear of participant COVID-19 exposure. The top virtual class barriers were lack of socialization (20% of PD group) and technology problems (74% of instructor group). Conclusion During COVID-19, there has been less in-person and more virtual exercise class participation in people with PD and decreased exercise quantity and intensity. Virtual classes may not fully meet the needs of people with PD, and primary barriers include technology and lack of socialization. Impact As COVID-19 restrictions wane, it is imperative to help people with PD increase exercise and activity. The barriers, needs, and facilitators identified in this study might help inform approaches to increase participation in exercise and activity for people with PD. Lay Summary During COVID-19, there has been less in-person and more virtual exercise class participation in people with PD and a decrease in exercise quantity and intensity. If you have PD, virtual classes might not fully meet your needs. Primary barriers may include technology problems and lack of social interaction.

PURPOSE: Rhythmic auditory stimulation such as listening to music can alleviate gait bradykinesia in people with Parkinson disease (PD) by increasing spatiotemporal gait features. However, evidence about what specific kinematic alterations lead to these improvements is limited, and differences in responsiveness to cueing likely affect individual motor strategies. Self-generated cueing techniques, such as singing or mental singing, provide similar benefits but no evidence exists about how these techniques affect lower limb joint movement. In this study, we assessed immediate effects of external and self-generated cueing on lower limb movement trajectories during gait. METHODS: Using 3D motion capture, we assessed sagittal plane joint angles at the hip, knee, and ankle across 35 participants with PD, divided into responders (n=23) and non-responders (n=12) based on a clinically meaningful change in gait speed. Joint motion was assessed as overall range of motion as well as at two key time points during the gait cycle: initial contact and toe-off. RESULTS: Responders used both cue types to increase gait speed and induce increases in overall joint ROM at the hip while only self-generated cues also increased ROM at the ankle. Increased joint excursions for responders were also evident at initial contact and toe off. CONCLUSIONS: Our results indicate that self-generated rhythmic cues can induce similar increases in joint excursions as externally-generated cues and that some people may respond more positively than others. These results provide important insight into how self-generated cueing techniques may be tailored to meet the varied individual needs of people with PD.

Background and purpose Previously, we showed that internal cues (such as singing) produce similar motor benefits as external cues (such as listening to music) for people with Parkinson disease (PD). This study takes that research further by exploring how singing-either aloud or mentally-at different tempos can ameliorate gait, and it offers insight into how internal cueing techniques may enhance motor performance for older adults and people with PD. Methods Sixty participants aged 50 years and older (30 female) were recruited; 30 had PD and 30 were healthy age-matched controls. Participants completed walking trials involving internal and external cueing techniques at 90%, 100%, and 110% of preferred cadence. The effects of different cue types and rates were assessed in a repeated-measures cross-sectional study by comparing gait characteristics (velocity, cadence, stride length) and variabilities (coefficients of variation of stride length, stride time, single support time). Results All participants modified their cadence and stride length during cued conditions, resulting in changes in gait velocity closely reflecting expected changes based upon cue rate. External cues resulted in increased gait variability, whereas internal cues decreased gait variability relative to uncued walking. Variability decreases were more substantial during mental singing at tempos at or above preferred cadence. Discussion and conclusions Matching movement to one's own voice improves gait characteristics while reducing gait variability for older adults and people with PD. Optimizing the use of internal cues to facilitate movement is an important step toward more effectively meeting the needs of people with gait disorders related to aging or neurological disease.Video Abstract available for more insights from authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A286).

Background People with Parkinson disease (PD) frequently experience low back pain (LBP), yet the impact of LBP on functional mobility, physical activity, and quality of life (QOL) has not been described in PD. Objective The objectives of this study were to describe body positions and functional activities associated with LBP and to determine the relationships between LBP-related disability and PD motor sign severity, physical activity level, and QOL. Design The study was a cross-sectional study. Methods Thirty participants with idiopathic PD (mean age = 64.6 years [SD = 10.3]; 15 women) completed the Revised Oswestry Disability Questionnaire (RODQ), a measure of LBP-related disability. PD motor symptom severity was measured using the Movement Disorder Society-Unified Parkinson Disease Rating Scale Part III (MDS-UPRDS III). The Physical Activity Scale for the Elderly (PASE) was used to measure self-reported physical activity. The Parkinson Disease Questionnaire-39 (PDQ-39) was used to measure QOL. Descriptive statistics were used to characterize LBP intensity and LBP-related disability. Spearman correlations were used to determine relationships between the RODQ and the MDS-UPDRS III, PASE, and PDQ-39. Results LBP was reported to be of at least moderate intensity by 63.3% of participants. LBP most frequently impaired standing, sleeping, lifting, and walking. The RODQ was significantly related to the MDS-UPDRS III (r = 0.38), PASE (r = −0.37), PDQ-39 summary index (r = 0.55), PDQ-39 mobility subdomain (r = 0.54), and PDQ-39 bodily pain subdomain (r = 0.44). Limitations Limitations included a small sample of people with mild to moderate PD severity, the fact that RODQ is a less frequently used measure of LBP-related disability, and the lack of a non-PD control group. Conclusions LBP affected walking, sleeping, standing, and lifting in this small sample of people with mild to moderate PD. Greater LBP-related disability was associated with greater motor sign severity, lower physical activity level, and lower QOL in people with PD.

Background Dysfunction of cerebellar vermis contributes to gait abnormalities in multiple conditions and may play a key role in gait impairment in Parkinson's disease (PD). Objective The purpose of this study was to investigate whether altered resting-state functional connectivity of the vermis relates to subsequent impairment of specific domains of gait in PD. Methods We conducted morphometric and resting-state functional connectivity MRI analyses contrasting 45 PD and 32 age-matched healthy participants. Quantitative gait measures were acquired with a GAITRite walkway at varying intervals after functional connectivity data acquisition. Results At baseline, PD participants had significantly altered functional connectivity between vermis and sensorimotor cortex compared with controls. Altered vermal functional connectivity with bilateral paracentral lobules correlated with subsequent measures of variability in stride length, step time, and single support time after controlling for confounding variables including the interval between imaging and gait measures. Similarly, altered functional connectivity between vermis and left sensorimotor cortex correlated with mean stride length and its variability. Vermis volume did not relate to any gait measure. PD participants did not differ from controls in vermis volume or cortical thickness at the site of significant regional clusters. Only altered lobule V:sensorimotor cortex functional connectivity correlated with subsequent gait measures in exploratory analyses involving all the other cerebellar lobules. Conclusions These results demonstrate that abnormal vermal functional connectivity with sensorimotor cortex, in the absence of relevant vermal or cortical atrophy, correlates with subsequent gait impairment in PD. Our data reflect the potential of vermal functional connectivity as a novel imaging biomarker of gait impairment in PD. © 2021 International Parkinson and Movement Disorder Society.

Advances in medical management of Parkinson's disease (PD) have resulted in living longer with disability. Although disability worsens over the course of the disease, there are signs of disability even in the early stages. Several studies reveal an early decline in gait and balance and a high prevalence of nonmotor signs in the prodromal period that contribute to early disability. There is a growing body of evidence revealing the benefits of physical therapy and exercise to mitigate motor and nonmotor signs while improving physical function and reducing disability. The presence of early disability coupled with the benefits of exercise suggests that physical therapy should be initiated earlier in the disease. In this review, we present the evidence revealing early disability in PD and the effectiveness of physical therapy and exercise, followed by a discussion of a secondary prevention model of rehabilitation to reduce early disability and optimize long-term outcomes.

Parkinson’s disease (PD) is a disabling neurodegenerative disease whose manifestations span motor, sensorimotor, and sensory domains. While current therapies for PD include pharmacological, invasive, and physical interventions, there is a constant need for developing additional approaches for optimizing rehabilitation gains. Mental imagery is an emerging field in neurorehabilitation and has the potential to serve as an adjunct therapy to enhance patient function. Yet, the literature on this topic is sparse. The current paper reviews the motor, sensorimotor, and sensory domains impacted by PD using gait, balance, and pain as examples, respectively. Then, mental imagery and its potential for PD motor and non-motor rehabilitation is discussed, with an emphasis on its suitability for addressing gait, balance, and pain deficits in people with PD. Lastly, future research directions are suggested.

Aim: To determine the effectiveness of a targeted dance intervention to improve walking speed for people with Parkinson disease (PD) by increasing motor motivation. Materials & methods: 11 participants with PD participated in a 6-week pilot study in which they learned a contemporary dance composed of walking steps and designed to mimic everyday walking. 1 h classes occurred twice-weekly. Results: Pre- and post-intervention assessments revealed a significant increase in gait speed (t9 = 3.30; p = 0.009), cadence (t9 = 2.345; p = 0.044), and stride length (t9 = 3.757; p = 0.005), and a significant decrease (improvement) in single support time variability (t9 = -2.744; p = 0.022). There were no significant changes in other measures of gait variability nor in motor symptoms, mood and anxiety, extent of life-space mobility, or quality of life. No adverse events were reported. Conclusion: Joywalk provides preliminary evidence that a targeted physical intervention for people with PD may specifically counter bradykinesia.

Subthalamic nucleus deep brain stimulation (STN-DBS) and levodopa are common treatment strategies for Parkinson’s disease (PD). However, the specific effects of these treatment strategies on balance and its components remain unclear. This cross-sectional study of people with PD and STN-DBS compared balance in the treated state (ON-medication/ON-stimulation) and untreated state (OFF-medication/OFF-stimulation) using the Balance Evaluation Systems Test (BESTest). Total BESTest scores from the treated and untreated states were compared to assess overall balance. Scores for the six sections of the BESTest were further compared to assess differences in specific components of balance between treatment conditions. Twenty-nine participants were included (Male: 21, Female: 8, Mean Age ± SD: 65.0 ± 6.9). Total BESTest scores showed improved balance in the treated state compared to the untreated state (Treated: 67.56 ± 10.92; Untreated: 59.23 ± 16.51, p < 0.001). Four sections (Stability Limits/Verticality, Anticipatory Postural Reactions, Sensory Orientation, Stability in Gait) of the BESTest significantly improved in the treated state relative to the untreated state, after correcting for multiple comparisons (p < 0.05). These results demonstrate that STN-DBS and levodopa improve overall balance and provide a first step toward understanding the effects of these treatment strategies on specific components of balance.

Background and purpose Improvement of walking performance is a primary goal for individuals poststroke or with Parkinson disease (PD) who receive physical therapy. More data about day-to-day variability of walking performance are critical for determining if changes in performance have occurred. Methods Baseline assessments were utilized from an ongoing, observational, prospective cohort study including 84 individuals poststroke (n = 37) or with PD (n = 47) receiving outpatient physical therapy services to improve mobility. Participants wore step activity monitors for up to 7 days to measure walking performance (steps per day, walking duration, maximum 30-minute output, and peak activity index) in daily life. Correlation analyses evaluated relationships between both capacity and performance measures as well as the relationships between mean performance variables and day-to-day variability. Regression analyses explored factors that contribute to variability in day-to-day performance variables. Results Mean steps per day for participants poststroke (5376 ± 2804) and with PD (8149 ± 4490) were consistent with previously reported cohorts. Greater amounts of walking were related to more day-to-day variability, with moderate correlations found between the mean and day-to-day variability of each performance measure, regardless of medical diagnosis or walking speed. Day-to-day variability is large (upwards of 50% of the mean), with the amount of walking performance serving as the primary predictor of day-to-day variability in walking performance. Discussion and conclusions The results of this study elucidate the factors that are related to and predict day-to-day variability of performance. Walking performance metrics should be evaluated over multiple days and greater variability should be anticipated with greater amounts of performance.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A319).

In this paper, we develop new methods to automatically detect the onset and duration of freezing of gait (FOG) in people with Parkinson disease (PD) in real time, using inertial sensors. We first build a physical model that describes the trembling motion during the FOG events. Then, we design a generalized likelihood ratio test framework to develop a two-stage detector for determining the zero-velocity and trembling events during gait. Thereafter, to filter out falsely detected FOG events, we develop a point-process filter that combines the output of the detectors with information about the speed of the foot, provided by a foot-mounted inertial navigation system. We computed the probability of FOG by using the point-process filter to determine the onset and duration of the FOG event. Finally, we validate the performance of the proposed system design using real data obtained from people with PD who performed a set of gait tasks. We compare our FOG detection results with an existing method that only uses accelerometer data. The results indicate that our method yields 81.03% accuracy in detecting FOG events and a threefold decrease in the false-alarm rate relative to the existing method.

Background Subthalamic nucleus deep brain stimulation (STN-DBS) reduces tremor, muscle stiffness, and bradykinesia in people with Parkinson’s Disease (PD). Walking speed, known to be reduced in PD, typically improves after surgery; however, other important aspects of gait may not improve. Furthermore, balance may worsen and falls may increase after STN-DBS. Thus, interventions to improve balance and gait could reduce morbidity and improve quality of life following STN-DBS. Physical therapy (PT) effectively improves balance and gait in people with PD, but studies on the effects of PT have not been extended to those treated with STN-DBS. As such, the efficacy, safety, and feasibility of PT in this population remain to be determined. The purpose of this pilot study is to address these unmet needs. We hypothesize that PT designed to target balance and gait impairment will be effective, safe, and feasible in this population. Methods/design Participants with PD treated with STN-DBS will be randomly assigned to either a PT or control group. Participants assigned to PT will complete an 8-week, twice-weekly PT program consisting of exercises designed to improve balance and gait. Control group participants will receive the current standard of care following STN-DBS, which does not include prescription of PT. The primary aim is to assess preliminary efficacy of PT on balance (Balance Evaluation Systems Test). A secondary aim is to assess efficacy of PT on gait (GAITRite instrumented walkway). Participants will be assessed OFF medication/OFF stimulation and ON medication/ON stimulation at baseline and at 8 and 12 weeks after baseline. Adverse events will be measured over the duration of the study, and adherence to PT will be measured to determine feasibility. Discussion To our knowledge, this will be the first study to explore the preliminary efficacy, safety, and feasibility of PT for individuals with PD with STN-DBS. If the study suggests potential efficacy, then this would justify larger trials to test effectiveness and safety of PT for those with PD with STN-DBS. Trial registration NCT03181282 (clinicaltrials.gov). Registered on 7 June 2017. Electronic supplementary material The online version of this article (10.1186/s40814-018-0243-2) contains supplementary material, which is available to authorized users.

Introduction Parkinson’s disease (PD) is a movement disorder caused by dysfunction in the basal ganglia (BG). Clinically relevant gait deficits, such as decreased velocity and increased variability, may be caused by underlying neural dysfunction. Reductions in resting-state functional connectivity (rs-FC) between networks have been identified in PD compared to controls; however, the association between gait characteristics and rs-FC of brain networks in people with PD has not yet been explored. The present study aimed to investigate these associations. Methods Gait characteristics and rs-FC MRI data were collected for participants with PD (N = 50). Brain networks were identified from a set of seeds representing cortical, subcortical, and cerebellar regions. Gait outcomes were correlated with the strength of rs-FC within and between networks of interest. A stepwise regression analysis was also conducted to determine whether the rs-FC strength of brain networks, along with clinical motor scores, were predictive of gait characteristics. Results Gait velocity was associated with rs-FC within the visual network and between motor and cognitive networks, most notably BG-thalamus internetwork rs-FC. The stepwise regression analysis showed strength of BG-thalamus internetwork rs-FC and clinical motor scores were predictive of gait velocity. Conclusion The results of the present study demonstrate gait characteristics are associated with functional organization of the brain at the network level, providing insight into the neural mechanisms of clinically relevant gait characteristics. This knowledge could be used to optimize the design of gait rehabilitation interventions for people with neurological conditions.

BACKGROUND AND PURPOSE The Maximum Step Length Test (MSLT), a measure of one's capacity to produce a large step, has been studied in older adults, but not in people with Parkinson disease (PD). We characterized performance and construct validity of the MSLT in PD. METHODS Forty participants (mean age: 65.12 ± 8.20 years; 45% female) with idiopathic PD completed the MSLT while "OFF" and "ON" anti-PD medication. Construct validity was investigated by examining relationships between MSLT and measures of motor performance. The following measures were collected: Mini-Balance Evaluation Systems Test (Mini-BESTest), Activities-specific Balance Confidence (ABC) scale, gait velocity, 6-minute walk test (6MWT), Movement Disorder Society-Unified Parkinson Disease Rating Scale subsection III (MDS-UPDRS III), and Timed Up and Go (TUG) test. A repeated-measures analysis of variance tested for main effects of medication and stepping direction and the interaction between the 2. Pearson or Spearman correlations were used to assess the relationships between MSLT and motor performance measures (α = 0.05). RESULTS Regardless of medication status, participants stepped further in the forward direction compared with the backward and lateral directions (P < 0.001). Participants increased MSLT performance when ON-medication compared with OFF-medication (P = 0.004). Regardless of medication status, MSLT was moderately to strongly related to Mini-BESTest, TUG, and 6MWT. DISCUSSION AND CONCLUSIONS People with PD stepped furthest in the forward direction when performing the MSLT. Increased MSLT performance was observed in the ON-medication state compared with OFF-medication; however, the small increase may not be clinically meaningful. Given the relationships between the MSLT and the Mini-BESTest, 6MWT, and TUG, MSLT performance appears to be associated with balance and gait hypokinesia in people with PD.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A186).

Background Freezing of gait (FOG) affects approximately 50% of people with Parkinson Disease (PD), impacting quality of life and placing financial and emotional strain on the individual and caregivers. People with PD and FOG have similar deficits in motor adaptation and cognition as individuals with cerebellar lesions, indicating the cerebellum may play a role in FOG. Objective To examine potential differences in cerebellar volumes and their relationships with cognition between PD with (FOG+) and without FOG (FOG-). Methods Sixty-three participants were divided into two groups, FOG+ (n = 25) and FOG- (n = 38), based on the New Freezing of Gait Questionnaire. Cognitive assessment included Trail Making, Stroop, Verbal Fluency, and Go-NoGo executive function tasks. All participants completed structural T1- and T2-weighted MRI scans. Imaging data were processed with FreeSurfer and the Spatially Unbiased Infratentorial toolbox to segment the cerebellum into individual lobules. Results FOG+ performed significantly worse on phonemic verbal fluency (F(1, 22) = 7.06, p = 0.01) as well as the Go-NoGo task (F(1, 22) = 9.00, p = 0.004). We found no differences in cerebellar volumes between groups (F(4, 55) = 1.42, p = 0.24), but there were significant relationships between verbal fluency measures and lobule volumes in FOG-. Conclusions These findings underscore the need for longitudinal studies to better characterize potential changes in cerebellar volume, cognitive function, and functional connectivity between people with PD with and without FOG.

We investigated the relationships between average gait speed collected with the 10 Meter Walk Test (Comfortable and Fast) and 6 Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10 Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r > 0.70, p < 0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p

Background Rhythmic auditory cueing has been widely studied for gait rehabilitation in Parkinson's disease (PD). Our research group previously showed that externally generated cues (i.e., music) increased gait variability measures from uncued gait, whereas self-generated cues (i.e., mental singing) did not. These different effects may be due to differences in underlying neural mechanisms that could be discerned via neuroimaging; however, movement types that can be studied with neuroimaging are limited. Objective The primary aim of the present study was to investigate the effects of different cue types on gait, finger tapping, and foot tapping, to determine whether tapping can be used as a surrogate for gait in future neuroimaging studies. The secondary aim of this study was to investigate whether rhythm skills or auditory imagery abilities are associated with responses to these different cue types. Methods In this cross-sectional study, controls (n = 24) and individuals with PD (n = 33) performed gait, finger tapping, and foot tapping at their preferred pace (UNCUED) and to externally generated (MUSIC) and self-generated (MENTAL) cues. Spatiotemporal parameters of gait and temporal parameters of finger tapping and foot tapping were collected. The Beat Alignment Task (BAT) and Bucknell Auditory Imagery Scale (BAIS) were also administered. Results The MUSIC cues elicited higher movement variability than did MENTAL cues across all movements. The MUSIC cues also elicited higher movement variability than the UNCUED condition for gait and finger tapping. Conclusions This study shows that different cue types affect gait and finger tapping similarly. Finger tapping may be an adequate proxy for gait in studying the underlying neural mechanisms of these cue types.

Individuals with Parkinson’s disease (PD) experience postural instability, low-back pain (LBP), and anxiety. These symptoms increase the risk of falls and decrease quality of life. Research shows yoga improves balance and decreases LBP and anxiety in healthy adults, but its effects in PD are poorly understood. All participants were part of a larger intervention study. Participants received pretest and posttest evaluations, including the Balance Evaluation Systems Test (BESTest), Beck Anxiety Inventory (BAI), and Revised Oswestry Disability Index (ROSW). Total scores for each measure, as well as individual balance system section scores from the BESTest (biomechanical constraints, stability limits/verticality, transitions/anticipatory, reactive, sensory orientation, and stability in gait) were compared within groups pre- to posttest. Participants in the yoga group (n = 13) completed a twice-weekly 12-week yoga interve n t i o n , whereas controls (n = 13) continued their usual routines for 12 weeks. Both the yoga (Z = −3.20, p = 0.001) and control (Z = −2.10, p = 0.040) groups improved on the BESTest total score. The control group showed no changes in individual balance systems, whereas the yoga group improved in stability limits/verticality (Z = −2.3, p = 0.020), transitions/ anticipatory (Z = −2.50, p = 0.010), reactive (Z = −2.70, p = 0.008), and sensory orientation (Z = −2.30, p = 0.020). ROSW decreased in the yoga group only (Z = −2.10, p = 0.030). BAI did not change in either group. Yoga is a nonpharmacological intervention that can improve balance and LBP in people with PD. This study demonstrated that yoga is feasible for people with PD, and participants reported high levels of enjoyment and intent to practice yoga after the study.

Cognitive-motor dual-tasking involves concurrent performance of two tasks with distinct cognitive and motor demands and is associated with increased fall risk. In this hypothesis-driven study, younger (18–30 years, n = 24) and older (60–75 years, n = 26) adults completed six walking tasks in triplicate. Participants walked forward and backward along a GAITRite mat, in isolation or while performing a verbal fluency task. Verbal fluency tasks involved verbally listing or typing on a smartphone as many words as possible within a given category (e.g., clothes). Using repeated measures MANOVA models, we examined how age, method of fluency task (verbal or texting), and direction of walking altered dual-task performance. Given that tasks like texting and backward walking require greater cognitive resources than verbal and forward walking tasks, respectively, we hypothesized older adults would show higher dual-task costs (DTCs) than younger adults across different task types and walking directions, with degree of impairment more apparent in texting dual-task trials compared to verbal dual-task trials. We also hypothesized that both age groups would have greater DTCs while walking backward than while walking forward, regardless of task. Independent of age group, velocity and stride length were reduced for texting compared to the verbal task during both forward and backward walking; cadence and velocity were reduced while walking forward compared to walking backward for the texting task; and stride length was reduced for forward walking compared to backward walking during the verbal task. Younger adults performed better than older adults on all tasks with the most pronounced differences seen in velocity and stride length during forward-texting and backward-texting. Interaction effects for velocity and stride length while walking forward indicated younger adults performed better than older adults for the texting task but similarly during the verbal task. An interaction for cadence during the verbal task indicated younger adults performed better than older adults while walking backward but similarly while walking forward. In summary, older adults experienced greater gait decrement for all dual-task conditions. The greater declines in velocity and stride length in combination with cadence being stable suggest reductions in velocity during texting were due to shorter strides rather than a reduced rate of stepping. Contrary to our hypotheses, we found greater DTCs while walking forward rather than backward, which may be due to reduced gait performance during single-task backward walking; thus, further decrements with dual-tasking are unlikely. These findings underscore the need for further research investigating fall risk potential associated with texting and walking among aging populations and how interventions targeting stride length during dual-task circumstances may improve performance.

Postural control integrates somatosensory, vestibular, and visual input to maintain balance. Age, dual-tasking (DT), and varying surfaces may impact postural control and lead to falls. Research suggests smartphone use is a growing safety hazard, as it reduces situational awareness while increasing dual-task costs (DTCs). Therefore, we examined postural control using a modern, motor-cognitive, dual-task paradigm and examined DTCs associated with age, surface characteristic, and type of DT. Younger (n=24) and older (n=26) participants completed three 30- second trials of six different task conditions. Participants either stood quietly (single-task) or performed a secondary, word generation task (dual-task) that included verbally listing words (verbal) or typing words (texting) on a smartphone within a given category (e.g., vegetables) while on a firm, stable surface (level floor) or compliant, unstable surface (foam pad). Repeated-measures MANOVAs tested differences in postural sway (measured by sway angle, velocity, and acceleration) between age groups and task conditions. Results indicated poorer performance on the verbal DT than texting DT while standing on the level floor; performance was similar between the two DTs when standing on the foam pad. We also found poorer performance on the foam pad compared to level floor while texting; performance was similar between surfaces for the verbal DT. Younger adults generally had better performance than older adults within each task, particularly for texting on the level floor. In summary, older age, verbal tasks, and compliant, unstable surfaces have greater impact on postural control parameters compared to younger age, texting, and firm, stable surfaces.