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Dive into the research topics where Ryan P. Duncan is active.

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Featured researches published by Ryan P. Duncan.


Neurorehabilitation and Neural Repair | 2012

Randomized Controlled Trial of Community-Based Dancing to Modify Disease Progression in Parkinson Disease

Ryan P. Duncan; Gammon M. Earhart

Background. Tango dancing has been effective in improving measures of physical function in people with Parkinson disease (PD). However, all previous studies were institution-based, tested participants on medication, and employed short-term interventions. Objective. To determine the effects of a 12-month community-based tango program for individuals with PD on disease severity and physical function. Methods. Sixty-two participants were randomly assigned to a twice weekly, community-based Argentine Tango program or a Control group (no intervention). Participants were assessed off anti-Parkinson medication at baseline, 3, 6, and 12 months. The primary outcome measure was the Movement Disorders Society–Unified Parkinson Disease Rating Scale 3 (MDS-UPDRS-3). Secondary outcome measures were the MDS-UPDRS-1, MDS-UPDRS-2, MiniBESTest balance test; Freezing of Gait Questionnaire (FOG_Q); 6-Minute Walk Test (6MWT); gait velocity for comfortable forward, fast as possible forward, dual task, and backward walking; and Nine-Hole Peg Test (9HPT). Results. Groups were not different at baseline. Overall, the Tango group improved whereas the Control group showed little change on most measures. For the MDS-UPDRS-3, there was no significant change in the Control group from baseline to 12 months, whereas the Tango group had a reduction of 28.7% (12.8 points). There were significant group by time interactions for MDS-UPDRS-3, MiniBESTest, FOG_Q, 6MWT, forward and dual task walking velocities, and 9HPT in favor of the dance group. Conclusions. Improvements in the Tango group were apparent off medication, suggesting that long-term participation in tango may modify progression of disability in PD.


Archives of Physical Medicine and Rehabilitation | 2013

Community-Based Argentine Tango Dance Program Is Associated With Increased Activity Participation Among Individuals With Parkinson's Disease

Erin R. Foster; Laura Golden; Ryan P. Duncan; Gammon M. Earhart

OBJECTIVE To determine the effects of a 12-month community-based tango dance program on activity participation among individuals with Parkinsons 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.


Archives of Physical Medicine and Rehabilitation | 2011

Five Times Sit-to-Stand Test Performance in Parkinson's Disease

Ryan P. Duncan; Abigail L. Leddy; Gammon M. Earhart

OBJECTIVES To (1) determine intrarater and test-retest reliability of the Five times sit-to-stand test (FTSTS) in Parkinsons 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, Parkinsons Disease Questionnaire-39, and Movement Disorders Society-Unified Parkinsons 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.


Parkinson's Disease | 2012

Accuracy of Fall Prediction in Parkinson Disease: Six-Month and 12-Month Prospective Analyses

Ryan P. Duncan; Abigail L. Leddy; James T. Cavanaugh; Leland E. Dibble; Terry Ellis; Matthew P. Ford; K. Bo Foreman; Gammon M. Earhart

Introduction. We analyzed the ability of four balance assessments to predict falls in people with Parkinson Disease (PD) prospectively over six and 12 months. Materials and Methods. The BESTest, Mini-BESTest, Functional Gait Assessment (FGA), and Berg Balance Scale (BBS) were administered to 80 participants with idiopathic PD at baseline. Falls were then tracked for 12 months. Ability of each test to predict falls at six and 12 months was assessed using ROC curves and likelihood ratios (LR). Results. Twenty-seven percent of the sample had fallen at six months, and 32% of the sample had fallen at 12 months. At six months, areas under the ROC curve (AUC) for the tests ranged from 0.8 (FGA) to 0.89 (BESTest) with LR+ of 3.4 (FGA) to 5.8 (BESTest). At 12 months, AUCs ranged from 0.68 (BESTest, BBS) to 0.77 (Mini-BESTest) with LR+ of 1.8 (BESTest) to 2.4 (BBS, FGA). Discussion. The various balance tests were effective in predicting falls at six months. All tests were relatively ineffective at 12 months. Conclusion. This pilot study suggests that people with PD should be assessed biannually for fall risk.


Physical Therapy | 2013

Comparative Utility of the BESTest, Mini-BESTest, and Brief-BESTest for Predicting Falls in Individuals With Parkinson Disease: A Cohort Study

Ryan P. Duncan; Abigail L. Leddy; James T. Cavanaugh; Leland E. Dibble; Terry Ellis; Matthew P. Ford; K. Bo Foreman; Gammon M. Earhart

Background The newly developed Brief–Balance Evaluation System Test (Brief-BESTest) may be useful for measuring balance and predicting falls in individuals with Parkinson disease (PD). Objectives The purposes of this study were: (1) to describe the balance performance of those with PD using the Brief-BESTest, (2) to determine the relationships among the scores derived from the 3 versions of the BESTest (ie, full BESTest, Mini-BESTest, and Brief-BESTest), and (3) to compare the accuracy of the Brief-BESTest with that of the Mini-BESTest and BESTest in identifying recurrent fallers among people with PD. Design This was a prospective cohort study. Methods Eighty participants with PD completed a baseline balance assessment. All participants reported a fall history during the previous 6 months. Fall history was again collected 6 months (n=51) and 12 months (n=40) later. Results At baseline, participants had varying levels of balance impairment, and Brief-BESTest scores were significantly correlated with Mini-BESTest (r=.94, P<.001) and BESTest (r=.95, P<.001) scores. Six-month retrospective fall prediction accuracy of the Brief-BESTest was moderately high (area under the curve [AUC]=0.82, sensitivity=0.76, and specificity=0.84). Prospective fall prediction accuracy over 6 months was similarly accurate (AUC=0.88, sensitivity=0.71, and specificity=0.87), but was less sensitive over 12 months (AUC=0.76, sensitivity=0.53, and specificity=0.93). Limitations The sample included primarily individuals with mild to moderate PD. Also, there was a moderate dropout rate at 6 and 12 months. Conclusions All versions of the BESTest were reasonably accurate in identifying future recurrent fallers, especially during the 6 months following assessment. Clinicians can reasonably rely on the Brief-BESTest for predicting falls, particularly when time and equipment constraints are of concern.


Disability and Rehabilitation | 2011

Measuring participation in individuals with Parkinson disease: relationships with disease severity, quality of life, and mobility

Ryan P. Duncan; Gammon M. Earhart

Purpose. Our aims were to: (1) describe participation in people with Parkinson disease (PD), (2) evaluate the relationship between quality of life and participation and (3) determine the mobliity measures which are predictive of participation. Methods. Participants with idiopathic PD (n  ==  62) were tested off medication for participation (Activity Card Sort), quality of life (PDQ-39), disease severity (MDS-UPDRS) and mobility (Berg Balance Scale, Five Time Sit to Stand (FTSTS), Six Minute Walk, forward walking velocity, dual-task walking velocity and Freezing of Gait Questionnaire (FOGQ)). Relationships of all variables to participation were examined using Pearson correlations. Subsequent regression analysis was employed to determine the mobility measures which best predicted the participation. Results. Participants with PD retained, on average, 78.3%% (SD  ==  15.6%%) of total activities. Participation was negatively correlated with all PDQ-39 domains (r range −0.36 to −0.78, all p  <  0.005) with the mobility domain having the strongest correlation. All mobility measures were significantly correlated with participation, with the final regression model including only FTSTS and FOGQ which combined explained 37%% of the variance in participation. Conclusions. Participation is highly related to mobility-related QOL and may be most impacted by ability to stand up from a chair and freezing of gait in those with PD.


PLOS ONE | 2014

Gait-Related Brain Activity in People with Parkinson Disease with Freezing of Gait

Daniel S. Peterson; Kristen A. Pickett; Ryan P. Duncan; Joel S. Perlmutter; Gammon M. Earhart

Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing- “FoG+” and people who do not experience freezing- ”FoG−“. Nine FoG+ and nine FoG− imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG− groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG−. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG−. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere.


Gait & Posture | 2012

Medication improves balance and complex gait performance in Parkinson disease

Marie E. McNeely; Ryan P. Duncan; Gammon M. Earhart

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


Journal of Alternative and Complementary Medicine | 2014

Are the Effects of Community-Based Dance on Parkinson Disease Severity, Balance, and Functional Mobility Reduced with Time? A 2-Year Prospective Pilot Study

Ryan P. Duncan; Gammon M. Earhart

OBJECTIVE To determine the effects of participation in a 2-year community-based dance class on disease severity and functional mobility in people with Parkinson disease (PD). DESIGN Randomized controlled trial. SETTINGS/LOCATION Dance classes took place in a community-based location. Outcome measures were collected in a university laboratory. PATIENTS Ten individuals with PD were randomly assigned to the Argentine tango (AT) group (n=5 [4 men]; mean age±standard deviation, 69.6±6.6 years) or the control group (n=5 [4 men]; mean age±standard deviation, 66±11.0 years). INTERVENTIONS The AT group participated in a community-based AT class for 1 hour twice weekly for 2 years. Control group participants were given no prescribed exercise. Blinded assessments occurred at baseline and 12 and 24 months. OUTCOME MEASURES Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) III, Mini-Balance Evaluation Systems Test (Mini-BESTest), gait velocity (forward and backward), Timed Up and Go and dual-task Timed Up and Go, Six-Minute Walk Test (6MWT), MDS-UPDRS II, MDS-UPDRS I, and Freezing of Gait Questionnaire. RESULTS There were no differences between groups at baseline. A significant group-by-time interaction (F [2,8]=17.59; p<0.0001) was noted for the MDS-UPDRS III, with the AT group having lower scores at 12 and 24 months than the controls. Significant interactions were also noted for the Mini-BESTest, MDS-UPDRS II and I, and 6MWT. CONCLUSION This is believed to be one of the longest-duration studies to examine the effects of exercise on PD. Participation in community-based dance classes over 2 years was associated with improvements in motor and nonmotor symptom severity, performance on activities of daily living, and balance in a small group of people with PD. This is noteworthy given the progressive nature of PD and the fact that the control group declined on some outcome measures over 2 years.


Journal of Neurologic Physical Therapy | 2013

Four square step test performance in people with Parkinson disease.

Ryan P. Duncan; Gammon M. Earhart

Background and Purpose: The Four Square Step Test (4SST), a quick and simple test of multidirectional stepping, may be useful in predicting falls in people with Parkinson disease (PD). We studied the reliability of the 4SST and its ability to discriminate between freezers and nonfreezers, between fallers and nonfallers, and factors predictive of 4SST performance in people with PD. Methods: Fifty-three individuals with idiopathic PD completed the full protocol, including the 4SST as well as measures of balance, walking, and disease severity on anti-PD medication. Results: Interrater (intraclass correlation coefficient [ICC] = 0.99) and test-retest reliability were high (ICC = 0.78). The median 4SST performance was 9.52 seconds. There was a significant difference between 4SST time on-medication versus off (P = 0.03), while differences between fallers and nonfallers (P = 0.06) and between freezers and nonfreezers (P = 0.08) did not reach significance. All outcome measures were significantly related to 4SST time. In an exploratory, simultaneous regression analysis, 56% of the variance in 4SST performance could be accounted for by 3 measures: Mini-Balance Evaluation Systems Test (Mini-BESTest), Five Time Sit to Stand, and Nine Hole Peg Test. The 4SST cutoff score for distinguishing fallers from nonfallers was 9.68 seconds (Area under curve = 0.65, sensitivity = 0.73, specificity = 0.57). The posttest probability of an individual with a score greater than the cutoff being a faller was 31% (pretest probability = 21%). Discussion and Conclusions: The 4SST is a reliable, quick test that can distinguish between on-and off-medication conditions in PD but is not as good as other tests (eg, Mini-BESTest) for distinguishing between fallers and nonfallers. Video Abstract available (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A31) for more insights from the authors.

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Gammon M. Earhart

Washington University in St. Louis

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Marie E. McNeely

Washington University in St. Louis

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Abigail L. Leddy

Rehabilitation Institute of Chicago

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Matthew P. Ford

University of Alabama at Birmingham

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Kristen A. Pickett

Washington University in St. Louis

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Joel S. Perlmutter

Washington University in St. Louis

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