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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ctim.2010.07.004 Byline: David Marchant (a), Jennifer L. Sylvester (b), Gammon M. Earhart (b)(c)(d) Keywords: Parkinson; Dance; Exercise; Balance; Gait Abstract: This study explored the feasibility and possible benefits of contact improvisation (CI) as an exercise intervention for individuals with PD. Author Affiliation: (a) Washington University in St. Louis, Performing Arts Department, United States (b) Washington University in St. Louis School of Medicine, Program in Physical Therapy, United States (c) Washington University in St. Louis School of Medicine, Department of Anatomy & Neurobiology, United States (d) Washington University in St. Louis School of Medicine, Department of Neurology, United States Article Note: (footnote) [star] This work was supported by grants from the Center for Programs at Washington University in St. Louis and the Missouri Physical Therapy Association. Additional support came from the Greater St. Louis Chapter of the American Parkinson Disease Association (APDA) and the APDA Center for Advanced PD Research at Washington University., [star][star] Work should be attributed to: Washington University in St. Louis School of Medicine, Program in Physical Therapy, Campus Box 8502, 4444 Forest Park Blvd., St. Louis, MO 63108-2212, United States.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ctim.2008.10.005 Byline: Madeleine E. Hackney (a), Gammon M. Earhart (a)(b)(c) Keywords: Rehabilitation; Parkinson disease; Gait; Balance; Dance Abstract: The goal of this pilot study was to determine the effects of short duration, intensive tango lessons on functional mobility in people with Parkinson disease. Author Affiliation: (a) Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO 63108, United States (b) Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63108, United States (c) Department of Neurology, Washington University School of Medicine, St. Louis, MO 63108, United States

Introduction: Gait dysfunction is common in people with Parkinson's disease (PD). Freezing of gait (FOG) is one such gait disturbance that significantly impacts mobility and quality of life in PD. Recent evidence suggests that cerebellar connectivity may differ in people with PD and FOG (PD+FOG) relative to those without FOG (PD-FOG). Investigation of gait adaptation, or the ability to change gait patterns in response to external perturbations, is cerebellum-dependent, is a practical means of probing cerebellar integrity and may provide additional insights regarding the FOG phenomenon.Methods: In this study, we investigated gait adaptation in PD and FOG by measuring after-effects, namely whole-body rotation, following stepping on a rotating disc in PD+FOG compared to PD-FOG and older healthy adults. We refer to the period of stepping on the rotating disc as the podokinetic (PK) stimulation and after-effects as podokinetic after-rotation (PKAR). Our primary measure of adaptation was the magnitude and rate of decay of the after-effects.Results: We noted that PKAR was diminished in PD+FOG compared to the other groups, indicating reduced storage of the adapted gait pattern in PD+FOG. In the PD groups, FOG explained about 20% of the variability in peak velocity. Furthermore, these differences were independent of stepping cadence or motor sign severity.Conclusion: Our results show that gait adaptation is impaired in PD+FOG, suggesting the cerebellum may be differentially impacted in PD+FOG compared to PD-FOG. This supports previous neuroimaging evidence of cerebellar dysfunction in PD+FOG. Overall, these data further our understanding of gait deficits in PD+FOG. [ABSTRACT FROM AUTHOR]

Visuomotor adaptation with prism glasses is a paradigm often used to understand how the motor system responds to visual perturbations. Both reaching and walking adaptation have been documented, but not directly compared. Because the sensorimotor environment and demands are different between reaching and walking, we hypothesized that characteristics of prism adaptation, namely rates and aftereffects, would be different during walking compared to reaching. Furthermore, we aimed to determine the impact of age on motor adaptation. We studied healthy younger and older adults who performed visually guided reaching and walking tasks with and without prism glasses. We noted age effects on visuomotor adaptation, such that older adults adapted and re-adapted slower compared to younger adults, in accord with previous studies of adaptation in older adults. Interestingly, we also noted that both groups adapted slower and showed smaller aftereffects during walking prism adaptation compared to reaching. We propose that walking adaptation is slower because of the complex multi-effector and multi-sensory demands associated with walking. Altogether, these data suggest that humans can adapt various movement types but the rate and extent of adaptation is not the same across movement types nor across ages. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To determine the effects of a 12-month community-based tango dance program on activity participation among individuals with Parkinson''s disease (PD). Design: Randomized controlled trial with assessment at baseline, 3, 6, and 12 months. Setting: Intervention was administered in the community; assessments were completed in a university laboratory. Participants: Volunteers with PD (n=62) enrolled in the study and were randomized to a treatment group; 10 participants did not receive the allocated intervention, and therefore the final analyzed sample included 52 participants. Interventions: Participants were randomly assigned to the tango group, which involved 12 months of twice-weekly Argentine tango dance classes, or to the no intervention control group (n=26 per group). Main Outcome Measure: Current, new, and retained participation in instrumental, leisure, and social activities, as measured by the Activity Card Sort (with the dance activity removed). Results: Total current participation in the tango group was higher at 3, 6, and 12 months compared with baseline (Ps≤.008), while the control group did not change (Ps≥.11). Total activity retention (since onset of PD) in the tango group increased from 77% to 90% (P=.006) over the course of the study, whereas the control group remained around 80% (P=.60). These patterns were similar in the separate activity domains. The tango group gained a significant number of new social activities (P=.003), but the control group did not (P=.71). Conclusions: Individuals with PD who participated in a community-based Argentine tango class reported increased participation in complex daily activities, recovery of activities lost since the onset of PD, and engagement in new activities. Incorporating dance into the clinical management of PD may benefit participation and subsequently quality of life for this population. [Copyright &y& Elsevier]

Abstract: Background: Dopaminergic medications and subthalamic nucleus deep brain stimulation (STN-DBS) alleviate motor symptoms in Parkinson disease, but balance and gait are more variably affected. Balance reports are particularly inconsistent. Further, despite their prevalence in daily life, complex gait situations including backward and dual task gait are rarely studied. We aimed to assess how medications, STN-DBS, and both therapies combined affect balance and complex gait. Methods: Twelve people with Parkinson disease were evaluated OFF medication with STN-DBS OFF and ON as well as ON medication with STN-DBS OFF and ON. Motor impairment was measured with the Movement Disorder Society Unified Parkinson Disease Rating Scale motor section (MDS-UPDRS-III). The Mini-Balance Evaluations Systems Test, timed-up-and-go, and dual task timed-up-and-go measured balance and mobility. Preferred-pace forward, fast as possible forward, backward, dual task forward, and dual task backward gait were also analyzed. Results: Medication improved MDS-UPDRS-III scores, dual task timed-up-and-go, and stride length across all gait tasks. STN-DBS improved MDS-UPDRS-III scores, balance scores, dual task timed-up-and-go, and stride length and velocity across all gait tasks. Medication and STN-DBS combined did not provide additional benefits over either therapy alone. Conclusions: Overall, dopaminergic medications and STN-DBS provided similar improvements in balance and gait tasks, although the effects of STN-DBS were stronger, potentially due to reductions in medication doses after surgery. Lack of synergistic effect of treatments may suggest both therapies improve balance and gait by influencing similar neural pathways. [Copyright &y& Elsevier]

Abstract: Difficulty switching between motor programs is a proposed cause of motor blocks in Parkinson disease (PD). Switching from one movement to another has been studied in the upper extremity and during postural control tasks, but not yet in the eyes and lower limb in PD. The purpose of this study was to compare movement orientation switching ability between people with PD and age-matched controls (CON) and to determine if switching ability is correlated between the eyes and lower limb. Twenty-six persons with PD and 19 age-matched controls participated. Movement orientation switching was studied in a seated position with the head fixed in a chinrest. In response to a randomly generated tone, participants switched from a continuous back-and-forth movement in either the horizontal or vertical orientation to the opposite orientation as quickly as possible. Lower limb movements were performed with the great toe pointing back and forth between targets positioned on a 45° angled floor platform. Eye movements were back and forth between the same targets. Eye and lower limb switch time was reduced in PD (p <0.01), but after normalizing switch time to movement velocity, no differences existed between PD and CON. Eye and lower limb switch times were correlated in PD (r =0.513, p <0.01) but not in CON. In PD, switch time and movement velocity of the lower limb, but not the eyes, correlated with bradykinesia and postural instability/gait. Our results suggest that individuals with PD experience movement-switching deficits with both the eyes and lower limb, perhaps driven by overall bradykinesia. [Copyright &y& Elsevier]

Abstract: Duncan RP, Leddy AL, Earhart GM. Five times sit-to-stand test performance in Parkinson''s disease. Objectives: To (1) determine intrarater and test-retest reliability of the Five times sit-to-stand test (FTSTS) in Parkinson''s disease (PD), (2) characterize FTSTS performance in PD at different disease stages, (3) determine predictors of FTSTS performance in PD, and (4) determine the utility of the FTSTS for discriminating between fallers and nonfallers with PD, identifying an appropriate cutoff score to delineate between these groups. Design: Measurement study of community-dwelling individuals with idiopathic PD. Setting: A medical school laboratory. Participants: Participants (N=82) were recruited via population-based sampling. The final sample included 80 participants. Two were excluded because of exclusion criteria and an unrelated illness, respectively. Interventions: Not applicable. Main Outcome Measures: FTSTS time (seconds) was the primary outcome measure. Secondary outcome measures included the Mini-Balance Evaluation Systems Test (Mini-BEST), Maximal Voluntary Isometric Contraction–Quadriceps, 9-Hole Peg Test (9HPT), 6-minute walk, Freezing of Gait Questionnaire, Activities-Specific Balance Confidence Scale, Physical Activity Scale for the Elderly, Parkinson''s Disease Questionnaire-39, and Movement Disorders Society–Unified Parkinson''s Disease Rating Scale. Results: Interrater and test-retest reliability for the FTSTS were high (intraclass correlation coefficients: .99 and .76, respectively). Mean FTSTS performance was 20.25±14.12 seconds. All mobility measures were significantly correlated with FTSTS (P<.01). The Mini-BEST and 9HPT together explained 53% of the variance in FTSTS. Receiver operating characteristic analysis determined a cutoff of 16.0 seconds (sensitivity, .75; specificity, .68) for discriminating between fallers and nonfallers, with an area under the curve of .77. Conclusions: The FTSTS is a quick, easily administered measure that is useful for gross determination of fall risk in individuals with PD. [Copyright &y& Elsevier]

Abstract: Parkinson disease (PD) reduces health-related quality of life (HRQoL), but exercise may improve HRQoL. This pilot study compared the effects of Tango, Waltz/Foxtrot, Tai Chi and No Intervention on HRQoL in individuals with PD. Seventy-five persons with PD (Hoehn and Yahr I-III) were assigned to 20 lessons of Tango, Waltz/Foxtrot, Tai Chi, or an untreated No Intervention group. Participants completed the PDQ-39 before and after participation in 20 classes or within 13weeks in the case of the No Intervention group. Two-way repeated measures ANOVAs determined differences between interventions. Tango significantly improved on mobility (p =0.03), social support (p =0.05) and the PDQ-39 SI (p <0.01) at post-testing. No significant changes in HRQoL were noted in the Waltz/Foxtrot, Tai Chi or No Intervention. Tango may be helpful for improving HRQoL in PD because it addresses balance and gait deficits in the context of a social interaction that requires working closely with a partner. [Copyright &y& Elsevier]

Abstract: Falvo MJ, Earhart GM. Six-minute walk distance in persons with Parkinson disease: a hierarchical regression model. Objectives: To determine the six-minute walk distance (6MWD) in subjects with Parkinson disease (PD) and to determine the impairments that contribute to walking capacity. Design: Descriptive cross-sectional study of subjects with PD. Setting: University laboratory. Participants: Subjects with PD (N=75; 65.0±9.5y) of mild to moderate severity, as defined by an average Hoehn and Yahr (HY) rating of 2.0±0.4 and Unified Parkinson Disease Rating Scale (UPDRS) motor score of 27±8.9, were tested on medication. Interventions: Not applicable. Main Outcome Measures: Subjects were administered the motor subsection of the UPDRS and completed the following tests: Berg Balance Scale (BBS), Timed Up & Go (TUG), and six-minute walk test. In addition, they also provided self-reports of freezing of gait and number of falls in the past 6 months. Results: The average 6MWD was 391.6±99.9m. All of the aforementioned tests, with the exception of fall number (P=.07), correlated significantly with 6MWD (r range, −.64 to .55). By using a hierarchical regression model, we entered age, HY, and UPDRS motor score into the first block (ie, set of independent variables) to represent parkinsonian characteristics, which explained a significant amount of variability in 6MWD (R 2=.196, P<.001). The second block entered (eg, functional measures scores, self-reports) explained a significant amount of additional variability (R 2 change=.355, P<.001). The TUG, BBS, and number of falls contributed independently in the presence of all independent variables. Conclusions: The 6MWD in subjects with PD is explained in part by disease-specific characteristics and perhaps to a greater extent by impaired balance and predisposition to falling. Training targeted at improving balance and reducing falling risk factors may increase 6MWD (ie, walking capacity) in subjects with PD. [Copyright &y& Elsevier]

Abstract: Two subjects with Parkinson disease (PD) who had difficulty turning, and freezing of gait triggered by turning, participated. Subjects completed four blocks of turning trials. Three blocks were conducted in the absence of treadmill intervention. Both subjects had consistent freezing across blocks prior to training and evidenced more freezing when turning left than right. The final block of turns was performed after 10–15min of training leftward turning on a rotating circular treadmill. Following training: (1) neither subject froze during leftward turns, (2) muscle activity normalized, and (3) turning times decreased for leftward turns. [Copyright &y& Elsevier]

Abstract: We examined the kinematics of voluntary turning in place at three different speeds and of inadvertent turning in place during attempts to step in place following stepping on a rotating disc (podokinetic after-rotation, PKAR). We hypothesized that voluntary turning in place, like online turning during walking, would be characterized by a top-down sequence of yaw rotations in the direction of the turn, i.e. the head would rotate first, followed by the trunk and then the foot. We also hypothesized that in place PKAR would be characterized by a bottom-up sequence of yaw rotations, i.e. the foot would rotate first, followed by the trunk and the head. The alternative possibility was that PKAR, like voluntary turning, would be initiated by the head and trunk and the foot would rotate last. As expected, voluntary turning in place was characterized by a top-down sequence similar to that noted previously during online turning in the midst of walking. Turning velocity did not alter the sequence of rotations in voluntary turning. In place PKAR was also characterized by a top-down sequence, indicating that PKAR may access the same neural circuits employed during voluntary turning. These data suggest that the rotating treadmill may be a useful training tool for addressing difficulties with turning that are experienced by individuals with Parkinson disease (PD). [Copyright &y& Elsevier]

Objective To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson disease (PD). Design Latent class analysis, specifically growth mixture modeling (GMM), of longitudinal fall risk trajectories. Setting Assessments were conducted at 1 of 4 universities. Participants Community-dwelling participants with PD of a longitudinal cohort study who attended at least 2 of 5 assessments over a 2-year follow-up period (N=230). Interventions Not applicable. Main Outcome Measures Fall risk trajectory (low, medium, or high risk) and stability of fall risk trajectory (stable or fluctuating). Fall risk was determined at 6 monthly intervals using a simple clinical tool based on fall history, freezing of gait, and gait speed. Results The GMM optimally grouped participants into 3 fall risk trajectories that closely mirrored baseline fall risk status ( P =.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium fall risk trajectories ( P <.001). Fluctuating fall risk (posterior probability <0.8 of belonging to any trajectory) was found in only 22.6% of the sample, most commonly among individuals who were transitioning to PIGD predominance. Conclusions Regardless of their baseline characteristics, most participants had clear and stable fall risk trajectories over 2 years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD. [ABSTRACT FROM AUTHOR]

Brain regions important for controlling movement are also responsible for rhythmic processing. In Parkinson disease (PD), defective internal timing within the brain has been linked to impaired beat discrimination, and may contribute to a loss of ability to maintain a steady gait rhythm. Less rhythmic gait is inherently less efficient, and this may lead to gait impairment including reduced speed, cadence, and stride length, as well as increased variability. While external rhythmic auditory stimulation (e.g. a metronome beat) is well-established as an effective tool to stabilize gait in PD, little is known about whether self-generated cues such as singing have the same beneficial effect on gait in PD. Thus, we compared gait patterns of 23 people with mild to moderate PD under five cued conditions: uncued, music only, singing only, singing with music, and a verbal dual-task condition. In our single-session study, singing while walking did not significantly alter velocity, cadence, or stride length, indicating that it was not excessively demanding for people with PD. In addition, walking was less variable when singing than during other cued conditions. This was further supported by the comparison between singing trials and a verbal dual-task condition. In contrast to singing, the verbal dual-task negatively affected gait performance. These findings suggest that singing holds promise as an effective cueing technique that may be as good as or better than traditional cueing techniques for improving gait among people with PD. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: The temporal relationship between disease and disability progression in Parkinson disease (PD) is not well understood. Our objective was to describe the natural, multidimensional trajectory of disability in persons with PD over a two-year period.Methods: We conducted a multi-center, prospective cohort study involving four institutions. Data were collected at baseline and at 6-month intervals over 2 years using standardized clinical tests representing three World Health Organization defined disability domains: impairment, activity limitation, and participation restriction. Unadjusted mixed effects growth models characterized trajectories of disability in the three disability domains. The data set was analyzed using restricted maximum likelihood (REML) estimation. Standardized estimates of change were also computed using Cohen's d for each measure.Results: Of the 266 enrolled participants, we analysed data from individuals who participated in at least 3 assessments (n = 207, 79%). Rates of disability progression over the 2-year period differed across domains. Moderate effects were detected for motor impairment (d = .28) and walking-related activity limitation (gait-related balance (d = .31); gait speed (d = .30)). Marginal effects were noted for upper extremity-related activity limitation (d = .11) and health-related quality of life participation restriction (d = .08).Conclusions: The natural trajectory of walking-related activity limitation was the most potent indicator of evolving disability, suggesting that routine assessment of walking and periodic rehabilitation is likely to be warranted for many persons with PD. Natural trajectories of disability provide important comparison data for future intervention studies. [ABSTRACT FROM AUTHOR]

Background Assessment of fall risk in an individual with Parkinson disease (PD) is a critical yet often time consuming component of patient care. Recently a simple clinical prediction tool based only on fall history in the previous year, freezing of gait in the past month, and gait velocity <1.1 m/s was developed and accurately predicted future falls in a sample of individuals with PD. METHODS: We sought to externally validate the utility of the tool by administering it to a different cohort of 171 individuals with PD. Falls were monitored prospectively for 6 months following predictor assessment. RESULTS: The tool accurately discriminated future fallers from non-fallers (area under the curve [AUC] = 0.83; 95% CI 0.76–0.89), comparable to the developmental study. CONCLUSION: The results validated the utility of the tool for allowing clinicians to quickly and accurately identify an individual's risk of an impending fall. [ABSTRACT FROM AUTHOR]

Abstract: Background: Gait impairments are well documented in those with PD. Prior studies suggest that gait impairments may be worse and ongoing in those with PD who demonstrate FOG compared to those with PD who do not. Purpose: Our aim was to determine the effects of manipulating step length and cadence individually, and together, on gait coordination in those with PD who experience FOG, those with PD who do not experience FOG, healthy older adults, and healthy young adults. Methods: Eleven participants with PD and FOG, 16 with PD and no FOG, 18 healthy older, and 19 healthy young adults walked across a GAITRite walkway under four conditions: Natural, Fast (+50% of preferred cadence), Small (−50% of preferred step length), and SmallFast (+50% cadence and −50% step length). Coordination (i.e. phase coordination index) was measured for each participant during each condition and analyzed using mixed model repeated measure ANOVAs. Results: FOG was not elicited. Decreasing step length alone or decreasing step length and increasing cadence together affected coordination. Small steps combined with fast cadence resulted in poorer coordination in both groups with PD compared to healthy young adults and in those with PD and FOG compared to healthy older adults. Conclusions: Coordination deficits can be identified in those with PD by having them walk with small steps combined with fast cadence. Short steps produced at high rate elicit worse coordination than short steps or fast steps alone. [Copyright &y& Elsevier]

Abstract: Walking on a rotating platform for 15 min causes healthy subjects to involuntarily turn when walking without vision. This adaptive response, called podokinetic after-rotation (PKAR), uses the same kinematic patterns as voluntary turning suggesting that PKAR and voluntary turning share common mechanisms. The purpose of this study is to determine whether people with Parkinson disease (PD), a condition that produces substantial disability from turning difficulties, can adapt to the rotating platform. Initial testing of people with PD revealed that most were unable to step on the rotating platform for 15 continuous minutes. We thus tested a less intense version of the paradigm in eight healthy people. On one day, subjects walked on the platform for 15 continuous minutes; on another day, they walked on the platform for three 5-minute intervals separated by 5-minute rests. After both sessions, subjects rested for 5 min then walked in place for 30 min without vision, while we recorded rotational velocity of PKAR. Continuous and interval protocols effectively elicited robust PKAR. We then tested eight subjects with PD and matched controls using the 5-minute interval protocol and recorded PKAR responses for 10 min. There were no significant differences between the PD and control groups. We conclude that PD subjects can adapt to the rotating platform and develop PKAR from interval training. Future studies are needed to determine whether the rotating platform may act as a rehabilitative tool to reinforce motor patterns for turning and alleviate turning difficulties in people with PD. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Objective: The burden of PD extends beyond physical limitations and includes significant psychosocial adjustments as individuals undergo changes to their self-perception and how others perceive them. There is limited quantitative evidence of the factors that contribute to self-perceived stigma, which we addressed in the present study.Methods: In 362 individuals with PD (157 women, 205 men), self-perceived stigma was measured by the four-item stigma subscale of the Parkinson's Disease Questionnaire (PDQ-39). Hierarchical linear modeling was used to assess predictors of stigma including demographics (age, gender) and disease characteristics: duration, stage (Hoehn & Yahr Scale), motor severity (Unified Parkinson's Disease Rating Scale, UPDRS, Part 3), activities of daily living (UPDRS Part 2), and depression (Geriatric Depression Scale). Predictor variables were chosen based on their significant correlations with the stigma subscale. Further analyses were conducted for men and women separately.Results: For the total sample, the full model accounted for 14% of the variance in stigma perception (p < .001). Younger age and higher depression scores were the only significant predictors (both p < .001). This pattern was also seen for the men in the sample. For the women, only depression was a significant predictor. Depression mediated the relation between stigma and activities of daily living.Conclusions: Younger age (men) and depression (men and women) were the primary predictors of self-perceived stigma in PD. Disease characteristics (motor and ADL) did not contribute to stigma perception. Depression is a potential treatment target for self-perceived stigma in PD. [ABSTRACT FROM AUTHOR]

Introduction: Exercise improves gait in Parkinson disease (PD), but whether exercise differentially affects people with PD with (freezers) and without freezing of gait (non-freezers) remains unclear. This study examines exercise's effects on gait performance, neural correlates related to these effects, and potential neural activation differences between freezers and non-freezers during motor imagery (MI) of gait.Methods: Thirty-seven participants from a larger exercise intervention completed behavioral assessments and functional magnetic resonance imaging (fMRI) scans before and after a 12-week exercise intervention. Gait performance was characterized using gait velocity and stride length, and a region of interest (ROI) fMRI analysis examined task-based blood oxygen-level dependent (BOLD) signal changes of the somatomotor network (SMN) during MI of forward (IMG-FWD) and backward (IMG-BWD) gait.Results: Velocity (F(1,34) = 55.04, p < 0.001) and stride length (F(1,34) = 77.58, p < 0.001) were significantly lower for backward versus forward walking in all participants. The ROI analysis showed freezers had lower BOLD signal compared to non-freezers in the cerebellum (F(1,32) = 7.01, p = 0.01), primary motor (left: F(1,32) = 7.09, p = 0.01; right: F(1,32) = 7.45, p = 0.01), and primary sensory (left: F(1,32) = 9.59, p = 0.004; right: F(1,32) = 8.18, p = 0.007) cortices during IMG-BWD only. The evidence suggests the exercise intervention did not affect gait or BOLD signal during MI.Conclusion: While all participants had significantly slower and shorter backward velocity and stride length, respectively, the exercise intervention had no effect. Similarly, BOLD signal during MI did not change with exercise; however, freezers had significantly lower BOLD signal during IMG-BWD compared to non-freezers. This suggests potential decreased recruitment of the SMN during MI of gait in freezers. [ABSTRACT FROM AUTHOR]

Cortical activity during motor task performance is attenuated in individuals with Parkinson disease (PD) relative to age-matched adults without PD, and this activity is enhanced with antiparkinson medication. It remains unclear, however, whether the relative change in cortical activity over the duration of the task, i.e., central adaptation, is affected individuals with PD, and if so, whether medication corrects for any unique behaviors. Movement-related cortical potentials (MRCPs) were recorded from scalp electrode sites Cz and C1 during 150 repetitive handgrip contractions at 70% of maximal voluntary contraction, in individuals with PD ( n  = 10) both ON and OFF of their PD medication, and neurologically normal age- and sex-matched controls ( n  = 10). Repetitions were divided into two Blocks (Block 1 and 2: repetitions 1–60 and 91–150, respectively), and the composite MRCP slopes were calculated during periods representing movement initiation (−2 s to movement onset) and execution (movement onset to 1 s). No significant interactions were noted for either comparison (PD OFF vs. control; PD OFF vs. PD ON), irrespective of electrode site (Cz or C1) or movement period (initiation or execution). Despite similar MRCP slopes and task performance, PD OFF endorsed greater perceived exertion during task performance than controls. In the present study, we observed attenuated task-related cortical activity among individuals with PD OFF relative to controls, but a similar relative adaptive response to a fatiguing task. Additionally, although antiparkinson medication enhanced cortical activity (PD OFF vs. PD ON), central adaptation was similar. [ABSTRACT FROM AUTHOR]

We investigated the relationships between average gait speed collected with the 10Meter Walk Test (Comfortable and Fast) and 6Minute 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 10Meter 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<0.001) related to the Comfortable 10 Meter Walk Test (r=0.75) and Fast 10Meter Walk Test (r=0.79) gait speed, with 56% and 62% of the variance in 6MWT gait speed explained, respectively. The regression model of 6MWT gait speed predicted by Comfortable 10 Meter Walk gait speed produced slope and intercept values near 1 and 0, respectively, especially for participants in H&Y stages II-IV. In contrast, slope and intercept values were further from 1 and 0, respectively, for the Fast 10Meter Walk Test. Comfortable 10 Meter Walk Test and 6MWT gait speeds appeared to be redundant in people with moderate to severe PD, suggesting the Comfortable 10 Meter Walk Test can be used to estimate 6MWT distance in this population. [ABSTRACT FROM AUTHOR]

Background: Freezing of gait (FOG) is a relatively common and remarkably disabling impairment associated with Parkinson disease (PD). Laboratory-based measures indicate that individuals with FOG (PD+FOG) have greater balance deficits than those without FOG (PD-FOG). Whether such differences also can be detected using clinical balance tests has not been investigated. We sought to determine if balance and specific aspects of balance, measured using Balance Evaluation Systems Test (BESTest), differs between PD+FOG and PD-FOG. Furthermore, we aimed to determine if time-efficient clinical balance measures (i.e. Mini-BESTest, Berg Balance Scale (BBS)) could detect balance differences between PD+FOG and PD-FOG.Methods: Balance of 78 individuals with PD, grouped as either PD+FOG (n=32) or PD-FOG (n=46), was measured using the BESTest, Mini-BESTest, and BBS. Between-groups comparisons were conducted for these measures and for the six sections of the BESTest using analysis of covariance. A PD composite score was used as a covariate.Results: Controlling for motor sign severity, PD duration, and age, PD+FOG had worse balance than PD-FOG when measured using the BESTest (p=0.008, F=7.35) and Mini-BESTest (p=0.002, F=10.37), but not the BBS (p=0.27, F=1.26). BESTest section differences were noted between PD+FOG and PD-FOG for reactive postural responses (p<0.001, F=14.42) and stability in gait (p=0.003, F=9.18).Conclusions: The BESTest and Mini-BESTest, which specifically assessed reactive postural responses and stability in gait, were more likely than the BBS to detect differences in balance between PD+FOG and PD-FOG. Because it is more time efficient to administer, the Mini-BESTest may be the preferred tool for assessing balance deficits associated with FOG. [ABSTRACT FROM AUTHOR]

Highlights: [•] Neural correlates of simple and complex gait imagery were assessed in people with Parkinson disease (PD). [•] PD exhibited more activity in the supplementary motor area during imagined turning than imagined forward or backward gait. [•] Across gait imagery tasks, globus pallidus activity was lower in PD compared to controls and was positively correlated to overground walking speed. [ABSTRACT FROM AUTHOR]

Abstract: Background: Freezing of gait is a debilitating and common gait disturbance observed in individuals with Parkinson''s disease (PD). Although the underlying mechanisms of freezing remain unclear, bilateral coordination of steps, measured as a phase coordination index, has been suggested to be related to freezing. Phase coordination index has not, however, been measured during tasks associated with freezing such as turning and backward walking. Understanding how bilateral coordination changes during tasks associated with freezing may improve our understanding of the causes of freezing. Methods: Twelve individuals with PD who freeze (freezers), 19 individuals with PD who do not freeze (non-freezers), and 10 healthy, age-matched older adults participated. General motor disease severity and freezing severity were assessed. Phase coordination index was calculated for all subjects during forward walking, backward walking, continuous turning in small radius circles, and turning in large radius circles. Results: Freezers and non-freezers had similar disease duration and general motor severity. Stepping coordination (measured as phase coordination index) was significantly worse in freezers compared to non-freezers and controls. Turning and backward walking, tasks related to freezing, resulted in worse coordination with respect to forward walking. Coordination was associated with severity of freezing scores such that worse coordination was correlated with more severe freezing. Conclusions: These results provide evidence that stepping coordination is related to freezing in people with PD. Identifying variables associated with freezing may provide insights into factors underlying this symptom, and may inform rehabilitative interventions to reduce its occurrence in PD. [Copyright &y& Elsevier]

• Visual network rs-FC was related to gait velocity in people with PD. • rs-FC between motor and cognitive networks was related to gait velocity. • Gait velocity and variability were associated with BG-thalamus rs-FC. • BG-thalamus rs-FC and MDS-UPDRS-III scores were predictive of gait velocity. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

• We examined 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. • External, not self-generated cues increased variability across movements and groups. • Finger tapping may be an adequate proxy for gait to study differences in cue types. • Groups did not differ in rhythm skills or auditory imagery scores. • Higher beat perception was associated with lower variability in tapping but not gait. 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. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]