Cory L. Christiansen

Walking economy in people with Parkinson's disease.

Gait dysfunction is an early problem identified by patients with Parkinsons disease (PD). Alterations in gait may result in an increase in the energy cost of walking (i.e., walking economy). The purpose of this study was to determine whether walking economy is atypical in patients with PD when compared with healthy controls. A secondary purpose was to evaluate the associations of age, sex, and level of disease severity with walking economy in patients with PD. The rate of oxygen consumption (V̇O2) and other responses to treadmill walking were compared in 90 patients (64.4 ± 10.3 years) and 44 controls (64.6 ± 7.3 years) at several walking speeds. Pearson correlation coefficients (r) were calculated to determine relationships of age, sex, and disease state with walking economy in PD patients. Walking economy was significantly worse in PD patients than in controls at all speeds above 1.0 mph. Across all speeds, V̇O2 was 6 to 10% higher in PD patients. Heart rate, minute ventilation, respiratory exchange ratio, and rating of perceived exertion were correspondingly elevated. No significant relationship of age, sex, or UPDRS score with V̇O2 was found for patients with PD. The findings suggest that the physiologic stress of daily physical activities is increased in patients with early to mid‐stage PD, and this may contribute to the elevated level of fatigue that is characteristic of PD.

Weight-bearing asymmetry in relation to measures of impairment and functional mobility for people with knee osteoarthritis.

OBJECTIVES To compare weight-bearing asymmetry (WBA) for people with unilateral knee osteoarthritis (OA) with that for healthy adults of similar age. In addition, associations between WBA and clinical measures of knee impairment and functional mobility were evaluated. DESIGN Cross-sectional design with age-matched control (CTL) group. SETTING Clinical research laboratory. PARTICIPANTS People with end-stage unilateral knee OA (n=50) (OA group) and healthy people (n=17) (CTL group) were enrolled in the study (N=67). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES WBA during a Five Times Sit-to-Stand Test (FTSST) based on average vertical ground reaction force under each foot, self-reported knee pain assessed using a Numerical Pain Rating Scale, knee extensor strength asymmetry based on peak isometric knee extension torque, knee motion asymmetry based on maximum passive knee extension and flexion angles, FTSST time, six-minute walk test distance, and Stair Climbing Test time. RESULTS The OA group demonstrated greater WBA than the CTL group during transitions between sitting and standing as measured by an absolute symmetry index (P=.015). No correlation was found between WBA and knee motion asymmetry, but comparisons of WBA with all the other outcome variables indicated fair relationships (range, r=.29-.44). CONCLUSIONS Weight-bearing asymmetry during transitions between sitting and standing can serve as a clinically relevant measure related to both knee impairment and functional mobility for people with unilateral knee OA.

Profile of Functional Limitations and Task Performance Among People With Early- and Middle-Stage Parkinson Disease

Background Overall functional ability declines over time in people with Parkinson disease (PD). Established benchmarks are needed to allow clinicians and researchers to facilitate meaningful interpretation of data. Objective The purposes of this study were: (1) to report typical values for standard measures of functional ability commonly used in intervention studies and clinical practice with individuals in the early and middle stages of PD and (2) to describe the profile of functional limitations using the Hoehn and Yahr (H&Y) stages of disease and Unified Parkinsons Disease Rating Scale (UPDRS) motor scores. Design Cross-sectional data were obtained from 5 different studies. Methods Three hundred thirty-nine patients were evaluated for disease severity (UPDRS motor score); functional capacity (Continuous Scale Physical Functional Performance Test [CS-PFP]); balance and gait (Functional Reach Test [FRT], Timed “Up & Go” Test [TUG], 360-degree turn, Six-Minute Walk Test [6MWT], and Two-Minute Walk Test); and basic functional activities (supine-to-stand task, stand-to-supine task, and functional axial rotation [FAR]). Results The mean UPDRS motor score for the sample was 39.2 (SD=12.93). At each stage of PD (from least to most involved), scores on functional measures indicated a significant and progressively reduced functional status. Limitations began early in the disease for the CS-PFP and FAR. Losses in performance were consistent across all stages of disease for the CS-PFP, FRT, 6MWT, and FAR. Several measures demonstrated meaningful losses of function only in later stages of disease. Findings extend current appreciation of functional limitations that begin early in PD and can guide the choice of functional outcome measures at different stages of disease severity. Limitations Data were obtained only from participants in H&Y stages 1 through 3 and only for some of the performance measures typically used. Conclusions The findings demonstrate that functional loss occurs at different points in the disease process, depending on the task under consideration. The resulting profile of functional limitations provides benchmarks that clinicians and researchers can use to interpret and monitor status of patients.

Weight-Bearing Asymmetry During Sit-Stand Transitions Related to Impairment and Functional Mobility After Total Knee Arthroplasty

OBJECTIVES To examine changes in weight-bearing (WB) asymmetry during sit-stand transitions for individuals during the first 6 months after unilateral total knee arthroplasty (TKA). Relationships between WB asymmetry, clinical measures of knee impairment, and functional mobility also were evaluated. DESIGN Prospective repeated-measures design. SETTING Clinical research laboratory. PARTICIPANTS People (N=36) with knee osteoarthritis (OA) scheduled to undergo unilateral TKA and a control (CTL) group (N=17 healthy people) were enrolled. INTERVENTION The TKA group participated in acute, home, and outpatient phases of exercise-based rehabilitation. MAIN OUTCOME MEASURES WB asymmetry measured during a 5-Times Sit-to-Stand Test (FTSST) based on average vertical ground reaction force under each foot, self-reported knee pain using a numerical pain rating scale, knee active range of motion symmetry, knee extensor strength symmetry, FTSST time, 6-minute walk test distance, and Stair Climbing Test time. RESULTS Compared with preoperative values, the TKA group showed greater WB asymmetry at 1 month after surgery (P<.001). By 6 months, the TKA group had less WB asymmetry than preoperative values (P<.001), which was not different from the CTL group. Symmetry in WB correlated with functional outcomes and symmetry of quadriceps strength for the TKA group 6 months postoperatively. CONCLUSIONS Patients with unilateral knee OA showed WB asymmetry during sit-stand transitions early after unilateral TKA that improved by 6 months after surgery and was no different from that for healthy people of similar age. For people in the first 6 months after TKA, greater symmetry was related to better function and strength symmetry.

Functional Outcomes After the Prosthetic Training Phase of Rehabilitation After Dysvascular Lower Extremity Amputation

To describe physical function outcomes and modes of physical therapy intervention for a cohort of patients with dysvascular lower extremity amputation (LEA) during the prosthetic training phase of rehabilitation.

Identification of trunk and pelvis movement compensations in patients with transtibial amputation using angular momentum separation.

Patients with unilateral dysvascular transtibial amputation (TTA) have a higher risk of developing low back pain than their healthy counterparts, which may be related to movement compensations used in the absence of ankle function. Assessing components of segmental angular momentum provides a unique framework to identify and interpret these movement compensations alongside traditional observational analyses. Angular momentum separation indicates two components of total angular momentum: (1) transfer momentum and (2) rotational momentum. The objective of this investigation was to assess movement compensations in patients with dysvascular TTA, patients with diabetes mellitus (DM), and healthy controls (HC) by examining patterns of generating and arresting trunk and pelvis segmental angular momenta during gait. We hypothesized that all groups would demonstrate similar patterns of generating/arresting total momentum and transfer momentum in the trunk and pelvis in reference to the groups (patients with DM and HC). We also hypothesized that patients with amputation would demonstrate different (larger) patterns of generating/arresting rotational angular momentum in the trunk. Patients with amputation demonstrated differences in trunk and pelvis transfer angular momentum in the sagittal and transverse planes in comparison to the reference groups, which indicates postural compensations adopted during walking. However, patients with amputation demonstrated larger patterns of generating and arresting of trunk and pelvis rotational angular momentum in comparison to the reference groups. These segmental rotational angular momentum patterns correspond with high eccentric muscle demands needed to arrest the angular momentum, and may lead to consequential long-term effects such as low back pain.

Preliminary investigation of rate of torque development deficits following total knee arthroplasty

BACKGROUND To assess changes in maximal strength and rate of torque development (RTD) following TKA, and examine the relationships between these measures and physical function. METHODS Thirty-five TKA patients and 23 controls completed isometric knee extensor torque testing preoperatively, 1, and 6 months after surgery. Maximal strength was calculated as the peak torque during a maximal voluntary isometric contraction (MVIC) of the knee extensor muscles, peak RTD (RTD(peak)) was calculated as the maximum value from the 1st derivative of the isometric knee extension torque data, RTD(25%) and RTD(50%) were calculated as the change in force over the change in time from force onset to 25% and 50% MVIC. Physical function was measured using a timed-up-and-go (TUG) and stair climbing test (SCT). RESULTS RTD was significantly lower in the TKA group, at all-time points, compared to the Controls. MVIC and RTD significantly decreased 1-month following surgery (p=0.000 for all measures). RTD(peak) measures added to linear regressions with strength improved the prediction of TUG scores (p=0.006) and the SCT scores (p=0.015) 1-month post-surgery. Adding RTD(50%) to the regression model, following MVIC, improved predicting both TUG (p=0.033) and SCT (p=0.024). At 6-months, the addition of RTD(25%) to the regression model, following MVIC, improved the prediction of TUG (p=0.037) and SCT (p=0.036). CONCLUSION Following TKA, physical function is influenced by both the maximal strength and the rate of torque development of the knee extensors, and the prediction of function is improved with the addition of RTD compared to that of maximal strength alone.

Factors predicting weight-bearing asymmetry 1 month after unilateral total knee arthroplasty: A cross-sectional study

UNLABELLED Factors predicting weight-bearing asymmetry (WBA) after unilateral total knee arthroplasty (TKA) are not known. However, identifying modifiable and non-modifiable predictors of WBA is needed to optimize rehabilitation, especially since WBA is negatively correlated to poor functional performance. The purpose of this study was to identify factors predictive of WBA during sit-stand transitions for people 1month following unilateral TKA. METHODS Fifty-nine people were tested preoperatively and 1month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit-to-Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations. RESULTS WBA, measured as the ratio of surgical/non-surgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD)) 1month after TKA. Regression analysis identified preoperative WBA (β=0.40), quadriceps strength ratio (β=0.31), and hamstrings strength ratio (β=0.19) as factors predictive of WBA 1month after TKA (R(2)=0.30). CONCLUSION Greater amounts of WBA 1month after TKA are predicted by modifiable factors including habitual movement pattern and asymmetry in quadriceps and hamstrings strength.

Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial

Importance Parkinson disease is a progressive neurologic disorder. Limited evidence suggests endurance exercise modifies disease severity, particularly high-intensity exercise. Objectives To examine the feasibility and safety of high-intensity treadmill exercise in patients with de novo Parkinson disease who are not taking medication and whether the effect on motor symptoms warrants a phase 3 trial. Design, Setting, and Participants The Study in Parkinson Disease of Exercise (SPARX) was a phase 2, multicenter randomized clinical trial with 3 groups and masked assessors. Individuals from outpatient and community-based clinics were enrolled from May 1, 2012, through November 30, 2015, with the primary end point at 6 months. Individuals with idiopathic Parkinson disease (Hoehn and Yahr stages 1 or 2) aged 40 to 80 years within 5 years of diagnosis who were not exercising at moderate intensity greater than 3 times per week and not expected to need dopaminergic medication within 6 months participated in this study. A total of 384 volunteers were screened by telephone; 128 were randomly assigned to 1 of 3 groups (high-intensity exercise, moderate-intensity exercise, or control). Interventions High-intensity treadmill exercise (4 days per week, 80%-85% maximum heart rate [n = 43]), moderate-intensity treadmill exercise (4 days per week, 60%-65% maximum heart rate [n = 45]), or wait-list control (n = 40) for 6 months. Main Outcomes and Measures Feasibility measures were adherence to prescribed heart rate and exercise frequency of 3 days per week and safety. The clinical outcome was 6-month change in Unified Parkinson’s Disease Rating Scale motor score. Results A total of 128 patients were included in the study (mean [SD] age, 64 [9] years; age range, 40-80 years; 73 [57.0%] male; and 108 [84.4%] non-Hispanic white). Exercise rates were 2.8 (95% CI, 2.4-3.2) days per week at 80.2% (95% CI, 78.8%-81.7%) maximum heart rate in the high-intensity group and 3.2 (95% CI, 2.8-3.6; P = .13) days per week at 65.9% (95% CI, 64.2%-67.7%) maximum heart rate in the moderate-intensity group (P < .001). The mean change in Unified Parkinson’s Disease Rating Scale motor score in the high-intensity group was 0.3 (95% CI, −1.7 to 2.3) compared with 3.2 (95% CI, 1.4 to 5.1) in the usual care group (P = .03). The high-intensity group, but not the moderate-intensity group, reached the predefined nonfutility threshold compared with the control group. Anticipated adverse musculoskeletal events were not severe. Conclusions and Relevance High-intensity treadmill exercise may be feasible and prescribed safely for patients with Parkinson disease. An efficacy trial is warranted to determine whether high-intensity treadmill exercise produces meaningful clinical benefits in de novo Parkinson disease. Trial Registration clinicaltrials.gov Identifier: NCT01506479

Effects of Weight-Bearing Biofeedback Training on Functional Movement Patterns Following Total Knee Arthroplasty: A Randomized Controlled Trial.

STUDY DESIGN Randomized controlled trial. OBJECTIVES To examine the effects of weight-bearing biofeedback training on weight-bearing symmetry and functional joint moments following unilateral total knee arthroplasty. BACKGROUND Individuals after unilateral total knee arthroplasty place more weight on the nonsurgical limb compared to the surgical limb during function. It is unknown whether targeted intervention can improve function in the surgical limb and resolve altered movement patterns. METHODS Twenty-six patients were randomly assigned to 2 groups (reload or control). The reload group had a standard-of-care rehabilitation augmented with weight-bearing biofeedback training, and the control group had a dose-matched standard-of-care rehabilitation. Lower-limb weight-bearing ratios were measured preoperatively and 6 and 26 weeks after total knee arthroplasty during a 5-time sit-to-stand test (FTSST) and walking. Secondary outcomes were FTSST time, walking speed, and lower-limb joint moments during the FTSST and walking. RESULTS No between-group differences were found in weight-bearing ratios. Five-time sit-to-stand test time improved in the reload group compared to the control group at 6 (P = .021) and 26 weeks (P = .021). There were no between-group differences in knee extension moment during the FTSST. Surgical-limb knee extension moments during walking increased from baseline to 26 weeks in the reload group and decreased in the control group (P = .008). CONCLUSION Weight-bearing biofeedback training had no effect on functional weight-bearing symmetry or knee extension moments during the FTSST. However, the biofeedback training resulted in increases of knee extension moments during gait and improved FTSST times. Trial registered at ClinicalTrials.gov (NCT01333189). Level of Evidence Therapy, level 2b.