Updating the Minimal Important Difference for Six-Minute Walk Distance in Patients With Chronic Obstructive Pulmonary Disease

Holland AE, Hill CJ, Rasekaba T, Lee A, Naughton MT, McDonald CF. Updating the minimal important difference for six-minute walk distance in patients with chronic obstructive pulmonary disease.

Objective

To establish the minimal important difference (MID) for the six-minute walk distance (6MWD) in persons with chronic obstructive pulmonary disease (COPD).

Design

Analysis of data from an observational study using distribution- and anchor-based methods to determine the MID in 6MWD.

Setting

Outpatient pulmonary rehabilitation program at 2 teaching hospitals.

Participants

Seventy-five patients with COPD (44 men) in a stable clinical state with mean age 70 years (SD 9y), forced expiratory volume in one second 52% (SD 21%) predicted and baseline walking distance 359 meters (SD 104m).

Interventions

Not applicable.

Main Outcome Measures

Participants completed the six-minute walk test before and after a 7-week pulmonary rehabilitation program. Participants and clinicians completed a global rating of change score while blinded to the change in 6MWD.

Results

The mean change in 6MWD in participants who reported themselves to be unchanged was 17.7 meters, compared with 60.2 meters in those who reported small change and 78.4 meters in those who reported substantial change (P=.004). Anchor-based methods identified an MID of 25 meters (95% confidence interval 20-61m). There was excellent agreement with distribution-based methods (25.5-26.5m, κ=.95). A change in 6MWD of 14% compared with baseline also represented a clinically important effect; this threshold was less sensitive than for absolute change (sensitivity .70 vs .85).

Conclusions

The MID for 6MWD in COPD is 25 meters. Absolute change in 6MWD is a more sensitive indicator than percentage change from baseline. These data support the use of 6MWD as a patient-important outcome in research and clinical practice.     

Estimating maximum work rate during incremental cycle ergometry testing from six-minute walk distance in patients with chronic obstructive pulmonary disease

Hill K, Jenkins SC, Cecins N, Philippe DL, Hillman DR, Eastwood PR. Estimating maximum work rate during incremental cycle ergometry testing from six-minute walk distance in patients with chronic obstructive pulmonary disease.

Objective

To develop a predictive equation to permit estimation of the maximum work rate (Wmax) achieved during an incremental cycle ergometry test from the measurement of 6-minute walk distance (6MWD) and its derivative, 6-minute walk work, which is the product of 6MWD and body weight.

Design

Cross-sectional observational study.

Setting

Outpatient physiotherapy and pulmonary physiology clinics in a tertiary hospital.

Participants

Patients (N=50; 36 men) with chronic obstructive pulmonary disease (forced expiratory volume in 1 second [FEV₁]=37%±11% of predicted).

Interventions

Not applicable.

Main Outcome Measures

Measurements were obtained of 6MWD and Wmax achieved during a laboratory-based, symptom-limited incremental cycle ergometry test. Linear regression analyses were performed using 6MWD, height, weight, and FEV₁ and using 6-minute walk work, height, and FEV₁ to determine their contribution to Wmax and to develop predictive equations for estimating Wmax.

Results

The equations derived to estimate Wmax using 6MWD and 6-minute walk work, respectively, were as follows: Wmax (W)=(0.122×6MWD)+(72.683×height [m])-117.109 (r²=.67, standard error of the estimate [SEE]=10.8W) and Wmax (W)=17.393+(1.442×6-minute walk work) (r²=.60, SEE=11.8W).

Conclusions

Wmax can be estimated from equations based on measurements of 6MWD or 6-minute walk work. The estimate of Wmax derived from either equation may provide a basis on which to prescribe cycle ergometry training work rates that comply with the current guidelines for pulmonary rehabilitation.     

Health Care Expenditures of Living With a Disability: Total Expenditures, Out-of-Pocket Expenses, and Burden, 1996 to 2004

Mitra S, Findley PA, Sambamoorthi U. Health care expenditures of living with a disability: total expenditures, out-of-pocket expenses, and burden, 1996 to 2004.

Objective

To estimate the health care expenditures associated with a disability and their recent trends.

Design

Retrospective analysis of survey data.

Setting

Not applicable.

Participants

Data from multiple years (1996-2004) of the Medical Expenditure Panel Survey (MEPS) for a nationally representative sample of civilian, noninstitutionalized U.S. population.

Interventions

Not applicable.

Main Outcome Measures

Health care expenditures consisted of total health care expenditures, total out-of-pocket (OOP) spending, and burden (the ratio of OOP to family income). All the analyses accounted for the complex survey design of the MEPS.

Results

Between 1996 and 2004, 6% to 9% of persons in the working-age group (21-61y) were identified as having a disability. Persons with disabilities consistently had higher total health expenditures, OOP spending, and burden compared with their counterparts without disabilities. In 2004, the average total expenditures were estimated at $10,508 for persons with disabilities and at $2256 for those without disabilities. In a multiple regression framework, persons with disabilities were consistently found to have higher expenditures, OOP spending, and burden between 1996 and 2004. Although expenditures, OOP spending, and burden increased over time, after controlling for demographic, socioeconomic, and health status, these 3 health care costs were not found to change disproportionately for persons with disability.

Conclusions

During the 1996 to 2004 period, persons with disabilities were consistently found to have significantly higher health expenditures, OOP spending, and burden compared with their counterparts without disabilities, which may adversely affect their health and standard of living.     

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.     

Lowering of Sensory, Motor, and Pain-Tolerance Thresholds With Burst Duration Using Kilohertz-Frequency Alternating Current Electric Stimulation: Part II

Ward AR, Lee Hung Chuen WL. Lowering of sensory, motor, and pain-tolerance thresholds with burst duration using kilohertz-frequency alternating current electric stimulation: part II.

Objective

To determine the optimum burst duration for discrimination between sensory, motor, and pain tolerance thresholds using 20-Hz bursts of kilohertz-frequency sinusoidal alternating current (AC) applied transcutaneously to human participants.

Design

A within-subject, repeated-measures trial.

Setting

A research laboratory.

Participants

Healthy young adults (N=20).

Interventions

Bursts of AC electric stimulation at frequencies of 1 and 4kHz. The burst frequency was 20Hz. Burst durations ranged from 250 microseconds (for 1 cycle of 4-kHz AC) and 1 millisecond (for 1 cycle of 1-kHz AC) to 50 milliseconds (continuous AC).

Main Outcome Measures

Measurement of sensory, motor, and pain-tolerance thresholds.

Results

Thresholds decreased to a minimum with increasing burst duration. The minimum threshold identified the utilization time over which summation of subthreshold stimuli occurs. Utilization times were different for sensory (∼20ms), motor (∼30ms), and pain (>50ms) and were much higher than found in a previous study that used a higher burst frequency (50Hz). As with the previous study, relative thresholds were found to vary with burst duration. Despite the very different utilization times, maximum separation between sensory, motor, and pain thresholds was found to occur with bursts in the range of 1 to 4 milliseconds, the same range found in the previous study.

Conclusions

Our conclusions concur with those reported previously and support the contention that short-duration kilohertz-frequency AC bursts (1-4ms) have a more useful role in rehabilitation than the long-duration kilohertz-frequency bursts that characterize Russian and interferential currents.     

Learning to Control Opening and Closing a Myoelectric Hand

Bouwsema H, van der Sluis CK, Bongers RM. Learning to control opening and closing a myoelectric hand.

Objective

To compare 3 different types of myoelectric signal training.

Design

A cohort analytic study.

Setting

University laboratory.

Participants

Able-bodied right-handed participants (N=34) randomly assigned to 1 of 3 groups.

Interventions

Participants trained hand opening and closing on 3 consecutive days. One group trained with a virtual myoelectric hand presented on a computer screen, 1 group trained with an isolated prosthetic hand, and 1 group trained with a prosthetic simulator. One half of the participants trained with their dominant side, and the other half trained with their nondominant side. Before and after the training period, a test was administered to determine the improvement in skill. Participants were asked to open and close the hand on 3 different velocities at command.

Main Outcome Measures

Peak velocity, mean velocity, and number of peaks in the myoelectric signal of hand opening and closing.

Results

No differences were found for the different types of training; all participants learned to control the myoelectric hand. However, differences in learning abilities were revealed. After learning, a subgroup of the participants could produce clearly distinct myoelectric signals, which resulted in the ability to open and close the hand at 3 different speeds, whereas others could not produce distinct myoelectric signals.

Conclusions

Acquired control of a myoelectric hand is irrespective of the type of training. Prosthetic users may differ in learning capacity; this should be taken into account when choosing the appropriate type of control for each patient.     

Validating the six-minute walk test as a measure of recovery after elective colon resection surgery

Moriello C, Mayo NE, Feldman L, Carli F. Validating the six-minute walk test as a measure of recovery after elective colon resection surgery.

Objective

To provide evidence for construct and longitudinal validity of the six-minute walk test (6MWT) as a measure of postsurgical recovery.

Design

Data from a randomized clinical trial.

Setting

A major teaching hospital in a Canadian urban city.

Participants

Patients (N=63) undergoing elective colon resection.

Interventions

Not applicable.

Main Outcome Measures

Functional walking capacity was measured using the 6MWT at before surgery and at 3 and 6 weeks after surgery.

Results

At 3 weeks, 26 (41%) patients recovered to baseline or greater on the 6MWT distance, and 37 (59%) were at baseline or better by 6 weeks postdischarge. At all time points, the 6MWT distance correlated with age, the American Society of Anesthesiologists (ASA) score of surgical risk, albumin, the physical function subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and the physical component summary score of the SF-36. Baseline 6MWT distance correlated with postoperative 6MWT recovery, and baseline SF-36 and ASA were associated with postoperative recovery. Patients with intraoperative complications had a clinically relevant lower 6MWT than those without complications at all time points.

Conclusions

This study provides evidence for construct validity and sensitivity to change for the 6MWT as a measure of surgical recovery.     

Postural Responses to Dynamic Perturbations in Amputee Fallers Versus Nonfallers: A Comparative Study With Able-Bodied Subjects

Vanicek N, Strike S, McNaughton L, Polman R. Postural responses to dynamic perturbations in amputee fallers versus nonfallers: a comparative study with able-bodied subjects.

Objectives

To quantify postural responses in amputee fallers versus nonfallers by using computerized dynamic posturography.

Design

All participants completed standard protocols on the Sensory Organization Test (SOT) and Motor Control Test (MCT) of the NeuroCom Equitest.

Setting

Human performance laboratory in a university in the United Kingdom.

Participants

Transtibial amputees (n=9) and able-bodied subjects (n=9) (all categorized into fallers and nonfallers according to their falls history in the previous 9mo).

Interventions

Not applicable.

Main Outcome Measures

Equilibrium and strategy scores on the SOT. Postural response latency and weight distribution on the MCT.

Results

Equilibrium scores were highest when somatosensory information was accurate, but there were no differences between the groups. Strategy scores were lower when visual cues and somatosensory information were inaccurate, and the fallers and nonfallers used a combination of ankle and hip strategies to prevent a loss of balance. The amputee nonfallers indicated they had a greater reliance on visual input even when it was inaccurate compared with the amputee fallers, whereas the control fallers used the hip strategy significantly more compared with the control nonfallers (SOT condition 6: 56±22 vs 72±10, P=.01). Weight distribution symmetry showed that the amputee nonfallers bore significantly more weight through their intact limb compared with the amputee fallers during backward and forward translations (P<.05).

Conclusions

The SOT and MCT appeared to be population specific and therefore did not reliably identify fallers among transtibial amputees or distinguish between community-dwelling control fallers and nonfallers. Amputee and control fallers can prevent a fall during challenging static and dynamic conditions by adapting their neuromuscular responses. The results from this study have important implications for amputee gait rehabilitation, falls prevention, and treatment programs.     

Can the Six-Minute Walk Test Predict Peak Oxygen Uptake in Men With Heart Transplant?

Doutreleau S, Di Marco P, Talha S, Charloux A, Piquard F, Geny B. Can the six-minute walk test predict peak oxygen uptake in men with heart transplant?

Objective

To determine whether the six-minute walk test (6MWT) might predict peak oxygen consumption (Vo₂peak) after heart transplantation.

Design

Case-control prospective study.

Setting

Public hospital.

Participants

Patients with heart transplant (n=22) and age-matched sedentary male subjects (n=13).

Interventions

Not applicable.

Main Outcome Measures

Exercise performance using a maximal exercise test, distance walked using the 6MWT, heart rate, and Vo₂peak.

Results

Compared with controls, exercise performance was decreased in patients with heart transplant with less distance ambulated (516±13m vs 592±13m; P<.001) and a decrease in mean Vo₂peak (23.3±1.3 vs 29.6±1mL·min⁻¹·kg⁻¹; P<.001). Patients with heart transplant showed an increased resting heart rate, a response delayed both at the onset of exercise and during recovery. However, the patient's heart rate at the end of the 6MWT was similar to that obtained at the ventilatory threshold. The formula did not predict measured V?o₂, with a weak correlation observed between the six-minute walk distance and both Vo₂peak (r=.53; P<.01) and ventilatory threshold (r=.53; P<.01) after heart transplantation. Interestingly, when body weight was considered, correlations coefficient increased to .74 and .77, respectively (P<.001).

Conclusions

In heart transplant recipients, the 6MWT is a safe, practical, and submaximal functional test. The distance-weight product can be used as an alternative method for assessing the functional capacity after heart transplantation but cannot totally replace maximal V?o₂ determination.     

Wheelchair-Related Falls in Veterans With Spinal Cord Injury Residing in the Community: A Prospective Cohort Study

Nelson AL, Groer S, Palacios P, Mitchell D, Sabharwal S, Kirby RL, Gavin-Dreschnack D, Powell-Cope G. Wheelchair-related falls in veterans with spinal cord injury residing in the community: a prospective cohort study.

Objectives

(1) To determine the incidence of wheelchair falls and fall-related injuries in persons with spinal cord injury (SCI) living in the community. (2) To predict wheelchair-related falls and associated injuries from specific parameters including characteristics of the wheelchair user, wheelchair type and features, health care practices, wheelchair activities, and physical environment.

Design

This prospective cohort study followed participants monthly over 1 year; data were collected through surveys, interviews, performance testing, observation, and medical records.

Setting

Three Veterans' Administration hospitals.

Participants

Convenience sample of community-dwelling persons with SCI who used a wheelchair as their primary means of mobility (N=702).

Interventions

Not applicable.

Main Outcome Measures

Self-reports of wheelchair falls and fall-related injuries, Wheelchair User Characteristics Survey, Health Status Checklist, Health-Related Behaviors, Zuckerman Sensation Seeking Scale, Wheelchair and Equipment-Related Behaviors, Wheelchair Characteristics, Wheelchair Skills Test, and Physical Environment Assessment.

Results

Of the 659 subjects who completed the study, 204 participants (31%) reported 553 fall events, and 95 subjects (14%) were injured as a result of wheelchair falls. A logistic regression model for predicting wheelchair falls identified 6 significant risk factors: pain in previous 2 months, alcohol abuse, greater motor function, history of previous fall, fewer SCI years, and shorter length of wheelchair. Eighty-two percent of the variance for wheelchair fall events was explained by these 6 variables. A logistic regression model for predicting injurious falls identified 4 significant risk factors: pain in previous 2 months, greater motor function, history of previous fall, and inaccessible home entrance. These 4 factors were able to explain 81% of the variance for injurious falls.

Conclusions

This is the first study to determine the incidence of wheelchair-related falls in community-dwelling people with SCI who use a wheelchair. Results indicate the incidence of falls was 31% and injurious falls was 14%. Those at greatest risk can be predicted from some readily available information regarding their clinical status, wheelchair features, and home environment.     

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.     

Evaluation of a stair-climbing power wheelchair in 25 people with tetraplegia

Laffont I, Guillon B, Fermanian C, Pouillot S, Even-Schneider A, Boyer F, Ruquet M, Aegerter P, Dizien O, Lofaso F. Evaluation of a stair-climbing power wheelchair in 25 people with tetraplegia.

Objective

To compare the performance of a power wheelchair with stair-climbing capability (TopChair) and a conventional power wheelchair (Storm3).

Design

A single-center, open-label study.

Setting

A physical medicine and rehabilitation hospital.

Participants

Patients (N=25) who required power wheelchairs because of severe impairments affecting the upper and lower limbs.

Interventions

Indoor and outdoor driving trials with both devices. Curb-clearing and stair-climbing with TopChair.

Main Outcome Measures

Trial duration and Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) tool; number of failures during driving trials and ability to climb curbs and stairs.

Results

All 25 participants successfully completed the outdoor and indoor trials with both wheelchairs. Although differences in times to trial completion were statistically significant, they were less than 10%. QUEST scores were significantly better with the Storm3 than the TopChair for weight (P=.001), dimension (P=.006), and effectiveness (P=.04). Of the 25 participants, 23 cleared a 20-cm curb without help, and 20 climbed up and down 6 steps. Most participants felt these specific capabilities of the TopChair—for example, curb clearing and stair climbing—were easy to use (22/25 for curb, 21/25 for stairs) and helpful (24/25 and 23/25). A few participants felt insecure (4/25 and 6/25, respectively).

Conclusions

The TopChair is a promising mobility device that enables stair and curb climbing and warrants further study.     

Asymptomatic median mononeuropathy among men with chronic paraplegia

Liang H-W, Wang Y-H, Pan S-L, Wang TG, Huang T-S. Asymptomatic median mononeuropathy among men with chronic paraplegia.

Objectives

To compare electrophysiologic abnormalities of the median nerve in asymptomatic paraplegic subjects and able-bodied controls and to examine the influence of personal factors on these parameters.

Design

Cross-sectional survey.

Setting

University hospital.

Participants

Forty-seven men with paraplegia and 36 able-bodied controls underwent nerve conduction studies on both upper limbs. All were free of hand numbness in the past month, diabetic mellitus, or neuromusculoskeletal injuries to the upper limbs.

Interventions

Not applicable.

Main Outcome Measure

Nerve conduction studies of the bilateral median and ulnar nerves.

Results

Although the 2 groups were of comparable age and had a similar body mass index (BMI), the subjects with paraplegia had a significantly higher proportion of asymptomatic median mononeuropathy than the controls (25.5% vs 5.6%, P=.02). The spinal cord injury (SCI) group had a prolonged median distal latency and a slowed digit-wrist sensory nerve conduction velocity. Multivariate general linear model analysis showed that prolonged motor and sensory latencies of the median nerve were associated with the SCI group and with greater BMI.

Conclusions

The asymptomatic subjects with paraplegia had a significantly higher frequency of median mononeuropathy than the able-bodied controls. There was also an association between BMI and distal latency of the median nerve.     

Longitudinal Changes in Physical Capacity Over 20 Years in Athletes With Spinal Cord Injury

Shiba S, Okawa H, Uenishi H, Koike Y, Yamauchi K, Asayama K, Nakamura T, Tajima F. Longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury.

Objective

To investigate the longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury (SCI).

Design

Longitudinal study (20-y follow-up).

Setting

Laboratory setting.

Participants

Persons with SCI (N=7).

Interventions

Not applicable.

Main Outcome Measures

Maximum oxygen consumption V?o₂max) measured in 1986-1988 and in 2006.

Results

Subjects with SCI maintained stable V?o₂max in 2006. Six of the 7 continued various wheelchair sports activities, while 1 person quit sports activities 1 year after the baseline study. The latter person showed reduced V?o₂max by 53%, while 2 persons who continued strenuous wheelchair sports activities showed increased V?o₂max by 43% and 45% after 20 years.

Conclusion

The results indicated that physical capacity reflected the level of sports activity in subjects with SCI who maintained sports activities.     

Relatives' Criticism Influences Adjustment and Outcome After Traumatic Brain Injury

Weddell RA. Relatives' criticism influences adjustment and outcome after traumatic brain injury.

Objectives

To apply some of the methods developed to study the effects of relatives' expressed emotion (EE) on psychiatric relapse rates and to test the prediction that relatives' criticism and psychiatric distress would be associated with outcome and emotional distress after traumatic brain injury (TBI).

Design

Retrospective cohort design with correlational analyses of quantitative and qualitative measures of TBI outcomes.

Setting

The author interviewed participants in the hospital. The research assistant interviewed close relatives at home.

Participants

Participants and relatives (N=78) were interviewed 34.3±15.2 months (mean ± SD) after a severe TBI.

Interventions

None.

Main Outcome Measures

Dependent variables in a series of hierarchical linear regression models were participants' scores on the Zung Depression Scale, Spielberger Trait Anxiety Inventory, State-Trait Anger Expression Inventory, an Anger Towards Relative questionnaire constructed for this study, and Extended Glasgow Outcome Scores. Participant-independent variables were social class, posttraumatic amnesia, Wechsler Memory Scale-Delayed Recall score, WAIS-R intelligence quotient, and a short version of the Smell Identification Test. Relative independent variables were the number of critical comments directed toward participants in the interview and psychiatric distress as measured by the General Health Questionnaire.

Results

The contributions of variance associated with relative independent variables (predominantly criticism) were significant in stage 2 of most hierarchical regression analyses after the adjustments for variance associated with participant independent variables made in stage 1.

Conclusions

Future application of EE research methods is warranted. If the present results are replicated, then evidence-based family interventions developed by EE researchers to reduce criticism might also improve TBI outcomes.     

What Are the Relations Between Voluntary Postural Sway Measures and Falls-History Status in Community-Dwelling Older Adults?

Tucker MG, Kavanagh JJ, Morrison S, Barrett RS. What are the relations between voluntary postural sway measures and falls-history status in community-dwelling older adults?

Objectives

To determine whether a series of voluntary postural sway tasks could differentiate and accurately identify the falls-history status of older adults, and to examine the relations between voluntary sway measures and falls risk.

Design

Case-control study.

Setting

University biomechanics laboratory.

Participants

Healthy community-dwelling older adults (N=51) aged 65 to 94 years who were divided into nonfaller (n=36), single faller (n=10), and multiple faller (n=5) groups based on a 12-month history of falls.

Interventions

Not applicable.

Main Outcome Measures

Participants underwent a falls-risk assessment using the Physiological Profile Assessment (PPA) and then performed 6 voluntary postural sway tasks. The tasks included maximum static leans, maximum voluntary sway, continuous voluntary sway, rapid initiation of voluntary sway, rapid termination of voluntary sway, and rapid orthogonal switches of voluntary sway between the anterior-posterior and medial-lateral directions. Center of pressure amplitudes and reaction time measures were examined using analysis of covariance, Pearson's correlation, and discriminant function analyses.

Results

Multiple fallers had increased age; increased falls risk; slower initiation, termination, and orthogonal switch reaction times; and reduced center of pressure amplitude during sway initiation and continuous voluntary sway compared with nonfallers. Few differences were observed between the nonfallers and single fallers. Voluntary sway measures were significantly correlated with each other and with PPA score. Two postural reaction time measures and age identified 80% of multiple fallers and 98% of nonmultiple fallers. Similarly, PPA score and age identified 80% of multiple fallers and 100% of nonmultiple fallers.

Conclusions

The slower and less effective balance responses of multiple fallers compared with nonfallers and the comparable sensitivity and specificity of PPA score and reactive voluntary sway measures indicate that postural reaction time is a strong determinant of falls risk.     

Evaluation of postural control in quiet standing using center of mass acceleration: comparison among the young, the elderly, and people with stroke

Yu E, Abe M, Masani K, Kawashima N, Eto F, Haga N, Nakazawa K. Evaluation of postural control in quiet standing using center of mass acceleration: comparison among the young, the elderly, and people with stroke.

Objective

To determine center of mass (COM) acceleration usefulness in the evaluation of postural control during quiet standing.

Design

Three-group comparison design.

Setting

A research laboratory.

Participants

Poststroke subjects (n=12), healthy elderly subjects (n=22), and healthy young subjects (n=25).

Interventions

Not applicable.

Main Outcome Measures

With a force platform, postural sway was evaluated by using the standard deviations of COM acceleration and center of pressure (COP) and COM (COP-COM) in which COP-COM represents the distance between the COP and the COM.

Results

COM acceleration and COP-COM variables were greater in the poststroke group than in the healthy groups (elderly and young) in the mediolateral (ML) direction. Both variables in the anteroposterior (AP) direction were greater in the poststroke group and the elderly group than in the young group. Furthermore, the correlations between COM acceleration and COP-COM in each group in each direction were shown to be significantly high (r range, .906-.979; P<.001).

Conclusions

COM acceleration was useful in the evaluation of postural control during quiet standing when comparing the young, the elderly, and poststroke patients. Additionally, COM acceleration and COP-COM in both the AP and ML directions during quiet standing were significantly and highly correlated. Thus, we proposed that COM acceleration can be an alternative and convenient measure instead of COP-COM in the evaluation of postural control.     

Within-day repeatability of the endurance shuttle walk test

Objective

To determine the need for a practice walk for the endurance shuttle walk test (ESWT) following the performance of two incremental shuttle walk tests (ISWTs) - one practice and one test - on the same day.

Design

Retrospective data analysis of shuttle walk test measurements. All participants had performed two ISWTs and two ESWTs at a single visit, prior to commencing pulmonary rehabilitation.

Setting

Outpatient physiotherapy department of a university hospital.

Participants

Forty-four patients (33 males, 11 females) with a primary diagnosis of chronic obstructive pulmonary disease, referred for routine pulmonary rehabilitation.

Measurements

Shuttle walk test distance and time, Borg breathlessness score, heart rate and pulsed oxygen saturation.

Results

The mean age of the group was 67.6 years [standard deviation (SD) 9.0] and mean forced expiratory volume in 1 second was 37% predicted (SD 13). The mean times walked during ESWTs 1 and 2 were 195 and 207 seconds (SD 115 and 138), respectively. Using the analysis recommended by Bland and Altman, the mean of the individual differences (d) between Tests 1 and 2 was 12 seconds, with limits of agreement from −88 to +112 seconds.

Conclusion

A practice endurance shuttle walk is unnecessary following performance of ISWTs on the same day.     

Effect of Ankle-Foot Orthosis Alignment and Foot-Plate Length on the Gait of Adults With Poststroke Hemiplegia

Fatone S, Gard SA, Malas BS. Effect of ankle-foot orthosis alignment and foot-plate length on the gait of adults with poststroke hemiplegia.

Objective

To investigate the effect of ankle-foot orthosis (AFO) alignment and foot-plate length on sagittal plane knee kinematics and kinetics during gait in adults with poststroke hemiplegia.

Design

Repeated measures, quasi-experimental study.

Setting

Motion analysis laboratory.

Participants

Volunteer sample of adults with poststroke hemiplegia (n=16) and able-bodied adults (n=12) of similar age.

Interventions

Subjects with hemiplegia were measured walking with standardized footwear in 4 conditions: (1) no AFO (shoes only); (2) articulated AFO with 90° plantar flexion stop and full-length foot-plate-conventionally aligned AFO (CAFO); (3) the same AFO realigned with the tibia vertical in the shoe-heel-height compensated AFO (HHCAFO); and (4) the same AFO (tibia vertical) with ¾ length foot-plate-¾ AFO. Gait of able-bodied control subjects was measured on a single occasion to provide a normal reference.

Main Outcome Measures

Sagittal plane ankle and knee kinematics and kinetics.

Results

In adults with hemiplegia, walking speed was unaffected by the different conditions (P=.095). Compared with the no AFO condition, all AFOs decreased plantar flexion at initial contact and mid-swing (P<.001) and changed the peak knee moment in early stance from flexor to extensor (P<.000). Both AFOs with full-length foot-plates significantly increased the peak stance phase plantar flexor moment compared with no AFO and resulted in a peak knee extensor moment in early stance that was significantly greater than control subjects, whereas the AFO with three-quarter length foot-plate resulted in ankle dorsiflexion during stance and swing that was significantly less than control subjects.

Conclusions

These findings suggest that when an articulated AFO is to be used, a full-length foot-plate in conjunction with a plantar flexion stop may be considered to improve early stance knee moments for people with poststroke hemiplegia.