Gait Patterns After Total Hip Arthroplasty and Surface Replacement Arthroplasty

Nantel J, Termoz N, Vendittoli P-A, Lavigne M, Prince F. Gait patterns after total hip arthroplasty and surface replacement arthroplasty.

Objective

To compare gait patterns in patients with total hip arthroplasty (THA) and surface hip arthroplasty.

Design

Observational study.

Setting

Outpatient biomechanical laboratory.

Participants

Two groups of 10 surface hip arthroplasty and THA patients and 10 control subjects participated in the study (N=30). The patients were volunteers recruited from a larger randomized study.

Interventions

Not applicable.

Main Outcomes Measures

Gait patterns, hip abductor muscle strength, clinical outcomes, and radiographic analyses were compared between groups.

Results

In the sagittal plane, the THA group showed a larger flexor moment and larger mechanical work in H2S and K3S power bursts compared with surface hip arthroplasty and control subjects. In the frontal plane, both THA and surface hip arthroplasty patients had smaller hip abductor muscles energy generation (H3F) than the control group. No difference was found for the hip abductor muscles strength.

Conclusions

In the THA group, the larger energy absorption in H2S and K3S would be a cost-effective mechanical adaptation to increase stability. The surface hip arthroplasty characteristics could allow the return to a more normative gait pattern compared with THA. The modification in the frontal plane in surface hip arthroplasty and THA would be related to the hip abductor muscles strength.     

The effects of hip and ankle stretching on gait function of older people

Christiansen CL. The effects of hip and ankle stretching on gait function of older people.

Objective

To examine effects of hip and ankle stretching on gait function of older people.

Design

Randomized controlled trial.

Setting

Flexibility training was performed in participants' homes. Assessments were performed in a biomechanics laboratory.

Participants

Forty healthy volunteers (mean age ± SD, 72.1±4.7y) randomized to 2 groups: intervention (n=20) and control (n=20).

Intervention

Intervention participants performed an 8-week stretching program, and control group participants maintained activity level for 8 weeks. One investigator made weekly visits to instruct and monitor participants.

Main Outcome Measures

Primary outcome measures were passive joint motion for hip extension and ankle dorsiflexion and freely chosen gait speed. Secondary outcome measures were gait parameters during freely chosen gait speed and set gait speed walking (stride length, joint displacement).

Results

Compared with the control group, the intervention group had increased combined hip and knee motion (P=.023), ankle motion (P=.020), and freely chosen gait speed (P=.016). The intervention group showed statistically nonsignificant trends of increased stride length at freely chosen gait speed and set gait speed.

Conclusions

Findings suggest joint motion is a modifiable impairment that is effectively targeted with flexibility training for older people. Participants in the intervention group had improvements in joint motion as well as increased freely chosen gait speed. Mechanisms responsible for changes in freely chosen gait speed warrant further investigation.     

The Influence of Applying Additional Weight to the Affected Leg on Gait Patterns During Aquatic Treadmill Walking in People Poststroke

Jung T, Lee D, Charalambous C, Vrongistinos K. The influence of applying additional weight to the affected leg on gait patterns during aquatic treadmill walking in people poststroke.

Objective

To investigate how the application of additional weights to the affected leg influences gait patterns of people poststroke during aquatic treadmill walking.

Design

Comparative gait analysis.

Setting

University-based aquatic therapy center.

Participants

Community-dwelling volunteers (n=22) with chronic hemiparesis caused by stroke.

Interventions

Not applicable.

Main Outcome Measures

Spatiotemporal and kinematic gait parameters.

Results

The use of an ankle weight showed an increase in the stance phase percentage of gait cycle (3%, P=.015) when compared with no weight. However, the difference was not significant after a Bonferroni adjustment was applied for a more stringent statistical analysis. No significant differences were found in cadence and stride length. The use of an ankle weight showed a significant decrease of the peak hip flexion (7.9%, P=.001) of the affected limb as compared with no weight condition. This decrease was marked as the reduction of unwanted limb flotation because people poststroke typically show excessive hip flexion of the paretic leg in the late swing phase followed by fluctuating hip movements during aquatic treadmill walking. The frontal and transverse plane hip motions did not show any significant differences but displayed a trend of a decrease in the peak hip abduction during the swing phase with additional weights. The use of additional weight did not alter sagittal plane kinematics of the knee and ankle joints.

Conclusions

The use of applied weight on the affected limb can reduce unwanted limb flotation on the paretic side during aquatic treadmill walking. It can also assist the stance stability by increasing the stance phase percentage closer to 60% of gait cycle. Both findings can contribute to the development of more efficient motor patterns in gait training for people poststroke. The use of a cuff weight does not seem to reduce the limb circumduction during aquatic treadmill walking.     

Locomotor treadmill training with partial body-weight support before overground gait in adults with acute stroke: a pilot study

McCain KJ, Pollo FE, Baum BS, Coleman SC, Baker S, Smith PS. Locomotor treadmill training with partial body-weight support before overground gait in adults with acute stroke: a pilot study.

Objective

To investigate the impact of locomotor treadmill training with partial body-weight support (BWS) before the initiation of overground gait for adults less than 6 weeks poststroke.

Design

Parallel group, posttest only.

Setting

Inpatient rehabilitation center.

Participants

Adults after first stroke admitted to an inpatient rehabilitation unit: treadmill group (n=7) and comparison group (n=7).

Interventions

Locomotor treadmill training with partial BWS or traditional gait training methods.

Main Outcome Measures

Gait kinematics, symmetry, velocity, and endurance at least 6 months postinsult.

Results

Data from 3-dimensional gait analysis and 6-minute walk test (6MWT) supported improved gait for adults postacute stroke who practiced gait on a treadmill before walking over ground. Gait analysis showed increased knee flexion during swing and absence of knee hyperextension in stance for the treadmill group. In addition, more normal ankle kinematics at initial contact and terminal stance were observed in the treadmill group. Improved gait symmetry in the treadmill group was confirmed by measures of single support time, hip flexion at initial contact, maximum knee flexion, and maximum knee extension during stance. The treadmill group also walked further and faster in the 6MWT than the comparison group.

Conclusions

Application of locomotor treadmill training with partial BWS before overground gait training may be more effective in establishing symmetric and efficient gait in adults postacute stroke than traditional gait training methods in acute rehabilitation.     

Physical Function, Gait, and Dynamic Balance of Transfemoral Amputees Using Two Mechanical Passive Prosthetic Knee Devices

Lythgo N, Marmaras B, Connor H. Physical function, gait, and dynamic balance of transfemoral amputees using two mechanical passive prosthetic knee devices.

Objective

To investigate the effect of the 3R90 and 3R92 (Otto Bock Healthcare) mechanical passive prosthetic knee devices on the physical function, gait, and dynamic balance (sudden stop and turn) of transfemoral amputees.

Design

Intervention study with crossover design.

Setting

University research center.

Participants

Men (N=5; mean age ± SD, 58.8±11.9y) with unilateral transfemoral amputation.

Intervention

Prosthetic knee joints (N=2; 3R90 and 3R92). Acclimatization ranged from 14 to 47 days (25.5±9.3d).

Main Outcome Measures

Physical function, gait, dynamic balance.

Results

The Timed Up and Go Test, 6-Minute Walk Test, and Four Square Step Test measures improved with the 3R92. Total scores on the Prosthesis Evaluation Questionnaire were similar for the 3R92 (82.0±6.3) and the participant's own or original device (83.9±4.8). These devices were rated higher than the 3R90 (65.5±16.8). Compared with the original device, gait velocity was significantly slower (5cm/s; P=.017) with the 3R92, but was unchanged for the 3R90. This difference was not considered clinically significant because the effect size was small (0.2). No other significant gait differences were found. Large temporal gait asymmetries observed with the original device remained with the 3R90 and 3R92 (step, ≈20%; single support, ≈30%; stance, ≈19%). Although no significant differences were found for the sudden-turn or sudden-stop tasks, the sudden-turn group success rates were highest with the original devices.

Conclusions

Gait and symmetry measures were unchanged. Gait speed was slower with the 3R92, but this was not considered to be clinically significant. Sudden-turn success rates generally were higher with the original devices. A crossover stepping movement was more difficult to implement than a side-stepping movement during sudden turns.     

The effect of exercise training in improving motor performance and corticomotor excitability in people with early Parkinson's disease

Fisher BE, Wu AD, Salem GJ, Song J, Lin C-H, Yip J, Cen S, Gordon J, Jakowec M, Petzinger G. The effect of exercise training in improving motor performance and corticomotor excitability in people with early Parkinson's disease.

Objectives

To obtain preliminary data on the effects of high-intensity exercise on functional performance in people with Parkinson's disease (PD) relative to exercise at low and no intensity and to determine whether improved performance is accompanied by alterations in corticomotor excitability as measured through transcranial magnetic stimulation (TMS).

Design

Cohort (prospective), randomized controlled trial.

Setting

University-based clinical and research facilities.

Participants

Thirty people with PD, within 3 years of diagnosis with Hoehn and Yahr stage 1 or 2.

Interventions

Subjects were randomized to high-intensity exercise using body weight-supported treadmill training, low-intensity exercise, or a zero-intensity education group. Subjects in the 2 exercise groups completed 24 exercise sessions over 8 weeks. Subjects in the zero-intensity group completed 6 education classes over 8 weeks.

Main Outcome Measures

Unified Parkinson's Disease Rating Scales (UPDRS), biomechanic analysis of self-selected and fast walking and sit-to-stand tasks; corticomotor excitability was assessed with cortical silent period (CSP) durations in response to single-pulse TMS.

Results

A small improvement in total and motor UPDRS was observed in all groups. High-intensity group subjects showed postexercise increases in gait speed, step and stride length, and hip and ankle joint excursion during self-selected and fast gait and improved weight distribution during sit-to-stand tasks. Improvements in gait and sit-to-stand measures were not consistently observed in low- and zero-intensity groups. The high-intensity group showed lengthening in CSP.

Conclusions

The findings suggest the dose-dependent benefits of exercise and that high-intensity exercise can normalize corticomotor excitability in early PD.     

Gait Analysis for Evaluating the Relationship Between Increased Signal Intensity on T2-Weighted Magnetic Resonance Imaging and Gait Function in Cervical Spondylotic Myelopathy

Kim CR, Yoo JY, Lee SH, Lee DH, Rhim SC. Gait analysis for evaluating the relationship between increased signal intensity on T2-weighted magnetic resonance imaging and gait function in cervical spondylotic myelopathy.

Objective

To determine relationships between increased signal intensity (ISI) on T2-weighted cervical spine magnetic resonance imaging (MRI) and parameters of gait analysis in patients with cervical spondylotic myelopathy (CSM).

Design

Retrospective comparative study.

Setting

Gait analysis laboratory.

Participants

Patients (N=36) who undertook cervical laminectomy or laminoplasty because of CSM.

Interventions

Not applicable.

Main Outcome Measures

Subjects were evaluated by using the modified Japanese Orthopaedic Association (JOA) scale, the Nurick scale, cervical spine MRI, and gait analysis. Two radiologists classified patients into 3 groups: intense, faint, and no ISI.

Results

Relative to patients without ISI, those with ISI showed significantly slower gait speed, longer step time, decreased single-limb support time, increased double-limb support time, and limited range of motion of knee and ankle (P<.05). Increased intensity tended to correlate with poor gait function including slower gait speed, longer step time, decreased single-limb support time, and increased double-limb support time. The modified JOA and Nurick scale did not correlate with ISI.

Conclusions

In patients with CSM who received surgical treatment, more intense ISI on T2-weighted MRI correlated preoperatively with increased difficulties in gait function. Gait analysis may be a useful tool for evaluating gait functions in cervical myelopathy.     

Novel Challenges to Gait in Parkinson's Disease: The Effect of Concurrent Music in Single- and Dual-Task Contexts

Brown LA, de Bruin N, Doan JB, Suchowersky O, Hu B. Novel challenges to gait in Parkinson's disease: the effect of concurrent music in single- and dual-task contexts.

Objective

To investigate the effect of concurrent music on parkinsonian gait in single- and dual-task contexts.

Design

A counterbalanced repeated-measure design.

Setting

A university balance research laboratory.

Participants

People with idiopathic Parkinson's disease (PD) (n=10) (67±7y) and healthy age-matched (65±6y) control subjects (n=10).

Intervention

Subjects walked at a self-selected pace along an unobstructed walkway in 4 differing test conditions. Test conditions were differentiated by the presence of music accompaniment (no music/music) and the presence of a secondary cognitive task (single/dual). Single- and dual-task conditions were randomized; trials were blocked by the presence of music and counterbalanced between subjects. Music was self-selected by subjects. The cognitive task consisted of serial subtractions (3's). Subjects were not instructed to attend to the music nor were they provided with instructions regarding task prioritization.

Main Outcome Measures

Mean gait velocity, stride length, and the percentage of the gait cycle spent in double-limb support.

Results

Gait among the PD patients was adversely affected by concurrent music. In contrast, gait performance in the control subjects showed no significant difference between no music and music conditions. The added requirement of a cognitive task differentially influenced gait performance in PD patients and control subjects, with PD patients displaying a further decrease in spatiotemporal parameters of gait and control subjects displaying a marginal improvement.

Conclusions

Gait impairments associated with PD are exacerbated in the presence of concurrent music, an effect that is further exaggerated by the addition of a cognitive task. These results have implications for patient safety in multitasking situations.     

Metabolic and Mechanical Energy Costs of Reducing Vertical Center of Mass Movement During Gait

Gordon KE, Ferris DP, Kuo AD. Metabolic and mechanical energy costs of reducing vertical center of mass movement during gait.

Objectives

To test the hypothesis that reducing vertical center of mass (COM) displacement will lower the metabolic cost of human walking. To examine changes in joint work associated with increasing and decreasing vertical COM movement during gait.

Design

Randomized repeated measures.

Setting

Human Neuromechanics Laboratory, University of Michigan.

Participants

Able-bodied subjects (N=10).

Interventions

Subjects walked at 1.2m/s on a treadmill and overground. Subjects manipulated vertical COM displacement either by adjusting stride length or by using visual feedback to reduce COM movement.

Main Outcome Measures

We measured kinematic and kinetic data to calculate vertical and lateral COM displacements, joint torques, and work. In addition, we collected oxygen consumption to calculated metabolic power.

Results

Increasing and decreasing vertical COM displacement beyond subjects' preferred range resulted in increases in the metabolic cost of walking. When vertical COM displacement was reduced, corresponding increases in positive ankle and hip work and negative knee work were observed.

Conclusions

Humans are capable of walking in a manner that will reduce COM displacement from normal. Decreasing vertical COM movement results in increases in metabolic energy costs because of greater mechanical work performed at the hip, knee, and ankle joints. Thus, reducing vertical COM movement is not a successful strategy for improving either metabolic or mechanical energy economy during normal walking by able-bodied subjects.     

Selective Tibial Neurotomy in the Treatment of Spastic Equinovarus Foot in Hemiplegic Patients: A 2-Year Longitudinal Follow-Up of 30 Cases

Deltombe T, Gustin T. Selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients: a 2-year longitudinal follow-up of 30 cases.

Objective

To assess the long-term efficacy of selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients.

Design

Intervention study (before-after trial) with an observational design and 2-year follow-up.

Setting

Spasticity group in a university hospital.

Participants

Hemiplegic patients (N=30) with spastic equinovarus foot.

Intervention

A selective neurotomy was performed at the level of the motor nerve branches of the tibial nerve.

Main Outcome Measures

Spasticity (Ashworth scale), muscle strength (Medical Research Council scale), passive ankle dorsiflexion, gait parameters (6 min walking test), and gait kinematics (video assessment) were assessed before and at 2 months, 1 year, and 2 years after selective tibial neurotomy.

Results

Compared with preoperative values, there was a statistically significant decrease in triceps surae spasticity, an increase in gait speed, and a reduction in equinus and varus in swing and stance phases at 2 months postoperatively. This improvement persisted at 1 and 2 years after selective tibial neurotomy. Selective tibial neurotomy does not induce permanent triceps muscle weakness or triceps surae-Achilles' tendon complex shortening.

Conclusion

This study confirms the long-lasting beneficial effect of selective tibial neurotomy on spasticity, gait speed, and equinovarus deformity in the treatment of spastic equinovarus foot in hemiplegic patients.     

Effects of Combining Electric Stimulation With Active Ankle Dorsiflexion While Standing on a Rocker Board: A Pilot Study for Subjects With Spastic Foot After Stroke

Cheng J-S, Yang Y-R, Cheng S-J, Lin P-Y, Wang R-Y. Effects of combining electric stimulation with active ankle dorsiflexion while standing on a rocker board: a pilot study for subjects with spastic foot after stroke.

Objective

To investigate the therapeutic effects of combining electric stimulation (ES) with active ankle dorsiflexion while standing on a rocker board in subjects with plantarflexor spasticity after stroke.

Design

Randomized controlled trial.

Setting

A rehabilitation medical center.

Participants

Subjects (N=15) with spastic foot after stroke.

Interventions

Subjects were randomly assigned to an experimental or a control group. The experimental group received ES of ankle dorsiflexors in concert with a motor training paradigm that required the subject to dorsiflex the ankles in response to a cue while standing on a rocker board. After 30 minutes of this exercise, subjects received ambulation training focusing on ankle control for 15 minutes. The control group received general range of motion and strength exercises for 30 minutes, followed by 15 minutes of ambulation training focusing on ankle control. Sessions occurred 3 times a week for 4 weeks.

Main Outcome Measures

Dynamic spasticity of plantarflexors, dorsiflexor muscle strength, balance performance, gait kinematics, and functional gait performance as assessed by the Emory Functional Ambulation Profile (EFAP) were used as outcome measurements.

Results

The experimental group demonstrated a greater decrease in dynamic ankle spasticity at a comfortable gait speed (P=.049), a greater improvement in spatial gait symmetry (P=.015), and a greater improvement in functional gait ability as indicated by the EFAP (P=.015) than the control group.

Conclusions

Our results suggest that repeated ES with volitional ankle movements can decrease dynamic ankle spasticity in subjects with stroke. Furthermore, such improvement parallels better gait symmetry and functional gait performance.     

Physical Function in Hip Osteoarthritis: Relationship to Isometric Knee Extensor Steadiness

Pua Y-H, Clark RA, Bryant AL. Physical function in hip osteoarthritis: relationship to isometric knee extensor steadiness.

Objective

To evaluate, in a community hip osteoarthritis sample, the cross-sectional associations of isometric strength and steadiness of the knee extensors and their interaction with physical performance measures of physical function.

Design

Cross-sectional.

Setting

Human movement laboratory of a university.

Participants

Sixty-seven adults (27 men and 40 women; age, 61±10y) with radiographically confirmed symptomatic hip osteoarthritis.

Interventions

Not applicable.

Main Outcome Measures

Participants performed isometric knee extensor steadiness and strength testing on a dynamometer. Physical function was assessed by using the habitual timed walk test and the self- and fast-paced stair-climbing tests.

Results

In the hierarchical regression models, although there were clear main effects of knee extensor steadiness on fast-paced stair performance, greater knee steadiness predictively associated with faster stair-climbing performance particularly in individuals with high knee extensor strength. In contrast, knee extensor steadiness was not related to gait speed regardless of knee extensor strength levels.

Conclusions

In patients with hip OA, knee extensor steadiness was positively associated with stair-climbing performance, particularly in those with high levels of knee extensor strength. These findings are of importance in developing intervention strategies, but they call for further study.     

Muscle strength and flexibility characteristics of people displaying excessive medial knee displacement

Bell DR, Padua DA, Clark MA. Muscle strength and flexibility characteristics of people displaying excessive medial knee displacement.

Objective

To determine differences in strength and range of motion (ROM) between participants who exhibit medial knee displacement (MKD) during a squat that is corrected by a heel lift and those who do not.

Design

Case control.

Setting

Sports medicine research laboratory.

Participants

Thirty-seven healthy subjects (control, 19; MKD, 18) with no lower-extremity injury in the past 6 months volunteered to participate.

Interventions

Not applicable.

Main Outcome Measures

Peak force was measured in newtons using a hand-held dynamometer and passive ROM was measured in degrees with a goniometer. Separate multivariate analyses of variance were used to determine differences in strength and ROM between groups. Post hoc testing was used to elucidate differences between groups.

Results

The MKD group had the following: greater hip external rotation strength (P=.03), increased hip extension strength (P=.01), less plantarflexion strength (P=.007), and increased hip external rotation ROM (P=.008).

Conclusions

The MKD group exhibited tight and weak ankle musculature. Interventions focusing on improving strength and ROM of the ankle may improve kinematics during a squat.     

Stand up and be counted: measuring time spent upright after hip fracture and comparison with community dwelling older people

Objectives

Following hip fracture, the amount of time an individual spends on their feet (‘uptime’) may be an important marker of recovery. Using an automated device that measured uptime (Uptimer), we aimed to: (1) compare hip fracture patients’ uptime with age- and gender-matched community dwelling older people; (2) identify whether uptime changed during the transition from hospital to home; and (3) examine the relationship between uptime and existing functional measures.

Design

Prospective, observational study.

Setting

Rehabilitation hospital and community.

Participants

Patients undergoing rehabilitation after hip fracture surgery who aimed to return home at the end of rehabilitation, and age- and gender-matched community dwellers.

Interventions

Patients received standard care.

Main outcome measures

Uptime over 24 hours was measured on three occasions in hip fracture patients: 1 week before, 1 day before and 1 week after discharge home. Uptime over 24 hours was measured once in age- and gender-matched community dwelling older people. Functional mobility, self-reported activity, pain, mood and endurance were also assessed.

Results

Thirteen hip fracture patients (mean age 80.4 years) and 13 community dwelling participants completed testing. Once home, hip fracture patients spent 3.4 hours/day (25th, 75th percentiles 2.8, 5.2) upright, while community dwelling healthy older people were upright for 6.5 hours/day (6.1, 8.7). A trend for uptime to increase between hospital and home was observed. Hip fracture uptime at home correlated significantly with self-reported activity, functional mobility and gait endurance (P < 0.05).

Conclusions

This study highlighted uptime limitations of hip fracture patients at home. We discuss possible future directions for research using the Uptimer.     

Mechanical and Sensorimotor Implications With Ankle Osteoarthritis

Hubbard TJ, Hicks-Little C, Cordova M. Mechanical and sensorimotor implications with ankle osteoarthritis.

Objective

To understand the mechanical and sensorimotor adaptations that may occur with ankle osteoarthritis (OA).

Design

Case-control.

Setting

Biodynamics research laboratory.

Participants

Subjects with ankle OA (n=8; 4 males, 4 females) were matched to healthy controls (n=8; 4 males, 4 females).

Interventions

Not applicable.

Main Outcome Measures

Mechanical joint stability was assessed with an instrumented ankle arthrometer. Static balance was measured using a force platform during a double-legged stance. Isometric ankle/foot complex strength in the sagittal and frontal plane was assessed with a handheld dynamometer. Last, subjective level of function was assessed using the foot and ankle disability index.

Results

There were significant group × side interactions for anterior displacement, inversion rotation, eversion rotation, ankle isometric strength, and the foot and ankle disability index (P<.05). The affected ankle of the OA group demonstrated significantly more mechanical stiffness, more impairments in ankle/foot isometric strength, and less subjective level of function than the matched controls. Additionally, the ankle OA group exhibited significantly more center of pressure displacement, total velocity, and medial-lateral velocity (P<.05).

Conclusions

These limitations observed in joint laxity, postural control, muscle strength, and perceived function provide evidence that patients with ankle OA display a number of characteristics that affect joint stability and overall function. These identified impairments necessitate the need for rehabilitation and exercise programs to be developed to help improve joint stability and function in patients with ankle OA.     

Detection of Gait and Postures Using a Miniaturized Triaxial Accelerometer-Based System: Accuracy in Patients With Mild to Moderate Parkinson's Disease

Dijkstra B, Kamsma YP, Zijlstra W. Detection of gait and postures using a miniaturized triaxial accelerometer-based system: accuracy in patients with mild to moderate Parkinson's disease.

Objective

To examine whether gait and postures can accurately be detected with a single small body-fixed device in patients with mild to moderate Parkinson's disease (PD).

Design

Results of a triaxial accelerometer-based method were evaluated against video observation scores (criterion measure). Study 1: Subjects performed basic mobility-related activities (walking, lying, sitting, standing) in a fixed and free sequence. Study 2: Subjects were monitored while doing similar activities as in study 1 and while doing usual domestic activities.

Setting

Study 1: Standardized set-up in a movement laboratory. Study 2: Home environment.

Participants

(N=37) Study 1: Patients with PD (n=32; mean age ± SD, 67.3±6.6y; mean disease duration ± SD, 6.1±3.4y). Study 2: Patients with PD (n=5; mean age ± SD, 76.0±7.3y; mean disease duration ± SD, 3.8±4.7y).

Interventions

Not applicable.

Main Outcome Measures

The degree of correspondence between the monitor and the video observation for the duration of each activity. Overall agreement, sensitivity, specificity, and positive predictive values were calculated.

Results

Study 1: Overall agreement ranged between 69.8% and 90.8% (fixed sequence) and 57.5% and 96.9% (free sequence). Study 2: Overall agreement ranged between 60.0% and 89.2%. Lying, sitting (home), and walking were detected most accurately with mean sensitivity varying from 81.7% to 99.9%. Lower values were found for sitting (laboratory), standing, and shuffling.

Conclusions

This triaxial monitor system is a practical and valuable tool for objective, continuous evaluation of walking and postures in patients with mild to moderate PD. Detection of sitting and standing requires further fine-tuning.     

Normalizing lower-extremity strength data for children without disability using allometric scaling

Wren TA, Engsberg JR. Normalizing lower-extremity strength data for children without disability using allometric scaling.

Objectives

To evaluate existing approaches for normalizing lower-extremity strength data and to develop normalization equations using allometric scaling in children without disabilities.

Design

Cross-sectional study evaluating traditional mass normalization and allometry as methods of adjusting lower-extremity muscle torques for the influence of body mass.

Setting

Motion analysis laboratory.

Participants

Thirty-nine children without disability (age range, 4−17y).

Interventions

Not applicable.

Main Outcome Measures

Maximum torque generated during hip abduction and adduction, knee extension and flexion, and ankle dorsiflexion and plantarflexion.

Results

Linear regressions of torque/mass^1.0 versus body mass and age produced slopes that differed significantly from zero (P<.001) for all muscle groups except the ankle plantarflexors versus body mass (P=.28). Regressions for torque/body mass index also produced slopes that differed significantly from zero (P<.001). Regressions of torque/(mass × height) produced slopes that differed from zero in some cases but not others. Allometric scaling exponents (exponent b) differed significantly from the theoretical value of 1.0 for all muscle groups except the ankle plantarflexors (1.32; 95% confidence interval, 0.98−1.67). Linear regressions performed using torque/mass^b produced slopes that did not differ significantly from zero for all muscle groups (P≥.10). Regressions performed using torque/mass^1.6 for the hip and knee and torque/mass^1.4 for the ankle also produced slopes that did not differ significantly from zero.

Conclusions

Traditional mass normalization does not effectively adjust for the influence of body mass. Allometric scaling performed using torque/mass^1.6 for the hip and knee or torque/mass^1.4 for the ankle provides more appropriate normalization.     

Implanted Electrical Stimulation of the Trunk for Seated Postural Stability and Function After Cervical Spinal Cord Injury: A Single Case Study

Triolo RJ, Boggs L, Miller ME, Nemunaitis G, Nagy J, Bailey SN. Implanted electrical stimulation of the trunk for seated postural stability and function after cervical spinal cord injury: a single case study.

Objectives

To explore and quantify the physical and functional effects of stabilizing the torso with electrical stimulation of the paralyzed hip and trunk musculature after motor complete tetraplegia.

Design

Single-subject case study with repeated measures and concurrent controls.

Setting

Academic outpatient rehabilitation center.

Participants

Forty-four-year-old man with C4 American Spinal Injury Association grade A tetraplegia 20 years postspinal cord injury.

Intervention

A surgically implanted multichannel pulse generator and intramuscular stimulating electrodes to activate lumbar erector spinae, quadratus lumborum, and gluteus maximus muscles bilaterally.

Main Outcome Measures

Outcomes assessed with and without stimulation included (1) spinal alignment and pelvic orientation, (2) pulmonary function and ventilatory volumes, (3) forward bimanual reaching distance, (4) seated stability and resistance to externally applied disturbances, (5) maximal force and speed of rowing-like movements, and the ability to (6) independently return to an erect seated position from full forward or lateral flexion and (7) roll in bed without assistance.

Results

Stimulation improved spinal convexity and kyphosis by 26° and 21°, reduced posterior pelvic tilt by 11°, increased forced expiratory volume and vital capacity by 10% and 22%, and improved forward reach by more than 7cm. Average resistance to sagittal disturbances increased by more than 40% (P<.002), and mean force exerted during underhanded pulling more than doubled (P=.014) with stimulation. Restoration of upright sitting in both sagittal and coronal planes and bed turning was made possible through appropriately timed activation of the hip and trunk muscles.

Conclusions

A neuroprosthesis for controlling the paralyzed torso can positively impact spinal alignment, seated posture, pulmonary function, trunk stability, and reach. Stimulation of hip and trunk muscles can improve performance of activities of daily living as well as enable independent wheelchair and bed mobility.     

Performance-based or self-report measures of physical function: which should be used in clinical trials of hip fracture patients?

Latham NK, Mehta V, Nguyen AM, Jette AM, Olarsch S, Papanicolaou D, Chandler J. Performance-based or self-report measures of physical function: which should be used in clinical trials of hip fracture patients?

Objectives

To assess the validity, sensitivity to change, and responsiveness of 3 self-report and 4 performance-based measures of physical function: activity measure for postacute care (AM-PAC) Physical Mobility and Personal Care scales, the Medical Outcomes Study 36-Item Short Form Health Survey Physical Function scale (SF-36 PF), the Physical Functional Performance test (PFP-10), the Short Physical Performance Battery (SPPB), a 4-meter gait speed, and the six-minute walk test (6MWT).

Design

A prospective observational study of patients after a hip fracture. Assessments were performed at baseline and 12 weeks postenrollment.

Setting

Inpatient and outpatient rehabilitation facilities in Norway, the United Kingdom, Sweden, Israel, Germany, the United States, Denmark, and Spain.

Participants

A sample of study participants (N=108) who had a hip fracture.

Interventions

Not applicable.

Main Outcome Measures

Assessments of validity (known-groups, concurrent, construct, and predictive), sensitivity to change (effect size, standardized response mean [SRM], SE of measure, minimal detectable change (MDC), and responsiveness (optimal operating cut-points and area under the curve) between baseline and 12-week follow-up.

Results

All physical function measures achieved comparably acceptable levels of validity. Odds ratios in predicting patient Global Assessment of Improvement at 12 weeks were as follows: AM-PAC Physical Mobility scale, 5.3; AM-PAC Personal Care scale, 3.6; SF-36 PF, 4.3; SPPB, 2.0; PFP-10, 2.5; gait speed, 1.9; and 6MWT, 2.4. Effect sizes and SRM exceeded 1 SD for all 7 measures. Percent of patients who exceeded the MDC₉₀ at week 12 were as follows: AM-PAC Physical Mobility scale, 90%; AM-PAC Personal Care scale, 74%; SF-36 PF, 66%; SPPB, 36%; PFP-10, 75%; gait speed, 69%; and 6MWT, 75%. When evaluating responsiveness using the area under receiver operating curves for each measure, all measures had acceptable responsiveness, and no pattern emerged of superior responsiveness depending on the type of measure used.

Conclusions

Findings reveal that the validity, sensitivity, and responsiveness of self-report measures of physical function are comparable to performance-based measures in a sample of patients followed after fracturing a hip. From a psychometric perspective, either type of functional measure would be suitable for use in clinical trials where improvement in function is an endpoint of interest. The selection of the most appropriate type of functional measure as the primary endpoint for a clinical trial will depend on other factors, such as the measure's feasibility or the strength of the association between the hypothesized mechanism of action of the study intervention and a functional outcome measure.     

Gait Training With Progressive External Auditory Cueing in Persons With Parkinson's Disease

Ford MP, Malone LA, Nyikos I, Yelisetty R, Bickel CS. Gait training with progressive external auditory cueing in persons with Parkinson's disease.

Objective

To investigate the progressively increasing external auditory cues during mobility training with persons with Parkinson's disease (PD).

Design

Experimental.

Setting

General community.

Participants

Convenience sample of persons with PD (N=12) who walked independently.

Interventions

Gait training to external auditory cues was based on a participant's comfortable walking pace. Training external auditory cues rates were increased if patients were able to maintain or increase stride length with increasing external auditory cues rate. Movement synchronization was not monitored during training. Participants trained for 30min/session, 3 sessions/wk, for 8 weeks.

Main Outcome Measures

Walking velocity, stride length, and cadence.

Results

Participants trained at a mean maximal rate of 157bpm. They showed a significant (P<.01) increase in walking velocity, stride length, and cadence after 8 weeks of training.

Conclusions

Walking velocity, stride length, and cadence can significantly improve when community-dwelling persons with PD participate in progressive mobility training.