Owen M. Evans

Deficit and change in gait velocity during rehabilitation after stroke

OBJECTIVE To quantify the initial deficit, change, and outcome in gait velocity during inpatient rehabilitation following stroke. DESIGN The initial deficit on admission to rehabilitation was quantified by comparing 42 stroke patients with 42 controls matched by gender and age. The change in the stroke patients during the next 8 weeks was quantified and gait outcome was compared with functional and normal criteria. SETTING Patients were referred from four inpatient rehabilitation centers at the time of admission following a median of 16.5 days in the acute hospital. PATIENTS SELECTION CRITERIA ability to give informed consent; unilateral first stroke; ability to walk 10 meters. INTERVENTION Patients participated in a median of 17.38 hours of individual physical therapy including a median of 6.92 hours of gait training during the 8 weeks. MAIN OUTCOME MEASURE Gait velocity. RESULTS Gait velocity was initially 38.6% (26.7m/min SD = 14.9) of the performance of controls and improved to 55.1% (38.1m/min). At outcome only 24% exceeded the 5th percentile of controls (48.1m/min) or the velocity required to cross the typical signalled intersection (46.2m/min). The change was only 26% of the initial deficit. Fifty-five percent of the patients improved beyond the 95% confidence intervals surrounding the error of measuring change. Indices of responsiveness indicated that there was a high signal-to-noise ratio and a robust effect size. CONCLUSION Gait velocity discriminated the effect of stroke and the change during rehabilitation.

Maximum voluntary weight-bearing by the affected and unaffected legs in standing following stroke

OBJECTIVE: To compare stroke patients to control subjects for ability to transfer body weight onto the affected and unaffected leg in standing; to investigate intra-session reliability. DESIGN: Comparative clinical study conducted within a single session. BACKGROUND: There is a paucity of quantitative data about maximum voluntary weight-bearing in patients during rehabilitation following stroke. METHODS: A Kistler force platform was used to quantify maximum amount of body weight transferred to a single limb in the lateral and forward directions during weight-shifting. Twelve control subjects matched by gender and age (median 64 years) were compared to 12 inpatient stroke patients after a median of 37 days post-onset. RESULTS: The median score for control subjects was approximately 95% of body weight to each leg in both directions. In contrast, stroke patients transferred less body weight (P<0.01) to the affected leg (65.5% lateral; 54.9% forward) and also to the unaffected leg (85.0% lateral; 80.1% forward). For the stroke patients, transfer of body weight was more challenging in the forward direction than the lateral direction on the affected leg (P<0.05). Relative to individual differences in the stroke group, error due to the repeated measurement process was low. CONCLUSION: The testing procedure was found to discriminate between stroke patients and control patients and had high retest reliability within a single session.

Angular movements of the pelvis and lumbar spine during self-selected and slow walking speeds

We studied the effect of walking at a self-selected and at a slower speed on the angular movements of the pelvis and lumbar spine. We also studied how interpretation of speed effects on lumbar spine movements was influenced by frame of reference, either relative to the pelvis or relative to a global reference frame. Twenty-seven subjects without pathology walked on a treadmill at either self-selected or 60% of self-selected speed. The movements of the pelvis and lumbar spine, as represented by surface markers, were recorded by videocameras and the three-dimensional angles computed by the PEAK motion measurement system. Results indicated that the amplitudes of pelvic list (P<0.05) and pelvic axial rotation (P<0. 05) were decreased at slow walking speed. Relative to the pelvis, the amplitude of lumbar lateral flexion was decreased with slower walking (P<0.01). In contrast, when lumbar spine movements were measured relative to a global reference frame, no differences were detected due to decreased walking speed. This suggests, firstly, that the effect of walking speed when evaluating the significance of decreased movements of the pelvis and of the lumbar spine (relative to the pelvis) of subjects walking at slower than self-selected speeds should be considered and secondly, that movement of the lumbar spine should be interpreted with respect to a frame of reference.

Predictors of Neck and Shoulder Pain in Non-Secretarial Computer Users

Abstract Poor typing skill is associated with long periods of time spent in extreme positions of neck flexion. There are clear links between sustained periods of neck flexion and musculoskeletal pain. Hours of computer use, perceived stress levels and workstation factors have also been found to be associated with upper extremity musculoskeletal pain. Previous studies of computer users have concentrated on secretarial and clerical workers. Recently, there has been considerable growth in computer usage by managerial and professional staff. Factors that may differ in this population are the level of typing skill, hours of computer use, stress levels and workstation factors. An epidemiological field study was conducted to determine the incidence of neck and shoulder pain in a non-secretarial population of computer users and to test the hypotheses that poor typing skill, hours of computer use, tension score and poor workstation set-up are associated with neck and shoulder complaints. There were 170 subjects from seven Hong Kong workplaces. A computer-based questionnaire determined hours of computer use, neck and shoulder pain and tension levels. Workstation and postural factors were observed by the researcher. Sixty-five percent of subjects reported pain. Using regression analysis, tension score and gender were the only factors found to be predictive of neck and shoulder pain. Relevance to industry High incidences of neck and shoulder pain were found in this non-secretarial population of computer users. Tension score was the major determinant of pain in this study. Remedial interventions need to address tension as well as workstation, computer usage and training factors.

Angular movements of the lumbar spine and pelvis can be reliably measured after 4 minutes of treadmill walking.

OBJECTIVE: To determine the familiarization period required to obtain consistent measurements of the angular movements of the lumbar spine and pelvis during treadmill walking. DESIGN: An in vivo study with repeated measures every 2 min over 10 min. BACKGROUND: Walking on a treadmill can initially be an unfamiliar experience. No data were available to indicate the length of time required for treadmill familiarization prior to taking measurements of the angular movements of the lumbar spine and pelvis. The familiarization period has implications for the use of this technique in clinical testing. METHODS: The angular movements of the lumbar spine and pelvis were examined by thePEAK 3D motion measurement system in 16 untrained, normal subjects walking for 10 min on a treadmill at either self-selected or 60% of self-selected speed. RESULTS: The reliability of the angular measurements of the spine and pelvis were all greater than 0.83 (ICC) after 4 min of treadmill walking and did not appear to increase after 4 min. No changes in the amplitudes of the angular movements of the lumbar spine and pelvis could be detected after 4 min of treadmill walking, or of the absolute difference scores beyond 2 min of treadmill walking, in either normal or slow-speed walking groups. CONCLUSIONS: Angular movements of the lumbar spine and pelvis were consistent after 4 min of treadmill walking by normal subjects, both at self-selected and slow walking speeds, indicating that reliable measurements of these parameters could be taken at that time.

Prediction of gait velocity in ambulatory stroke patients during rehabilitation

OBJECTIVE To quantify prediction of gait velocity in ambulatory stroke patients during rehabilitation. DESIGN Single group (n = 42) at the beginning of rehabilitation (Test 1) and 8 weeks later (Test 2). SETTING Inpatient rehabilitation. PATIENTS Unilateral first stroke; informed consent; able to walk 10 meters. MEASURES INDEPENDENT VARIABLES Gait velocity at Test 1, age, time from stroke to Test 1, side of lesion, neglect. DEPENDENT VARIABLES Gait velocity at Test 2, gait velocity change. RESULTS The correlation between initial gait velocity and gait velocity outcome at Test 2 was of moderate strength (r2 = .62, p<.05). However, even at its lowest, the standard error of prediction for an individual patient was 9.4 m/min, with 95% confidence intervals extending over a range of 36.8 m/min. Age was a weak predictor of gait velocity at Test 2 (r2 = -.10, p<.05). Gait velocity change was poorly predicted. The only significant correlations were initial gait velocity (r2 = .10, p<.05) and age (r2 = .10, p<.05). CONCLUSION While the prediction of gait velocity at Test 2 was of moderate strength on a group basis, the error surrounding predicted values of gait velocity for a single patient was relatively high, indicating that this simple approach was imprecise on an individual basis. The prediction of gait velocity change was poor. A wide range of change scores was possible for patients, irrespective of their gait velocity score on admission to rehabilitation.

Performance in the stability limits test during rehabilitation following stroke

The extent to which the standing posture could be perturbed voluntarily by having the subject displace the centre of pressure (CP) to the outer limits of the base of support was investigated in 20 stroke patients who were undertaking inpatient rehabilitation and 20 control subjects matched by gender and age. The mean age of the stroke patients was 50.7 years (S.D. = 18.5) and testing occurred after a median of 10 weeks post-onset. A force platform was used to quantify displacement of the CP in the forward and backward directions and laterally to each leg during sustained weight-shifting. The distribution of weight between the legs was also quantified during standing and antero-posterior (AP) weight-shifting by measuring the mean position of the CP in the lateral axis. Compared to controls, the stroke patients showed deficits in weight-shifting in both forward (P < 0.01) and backward (P < 0.01) directions. Forward displacement was greater than backward displacement in both groups (P < 0.01). During standing and AP weight-shifting stroke patients deviated from the mid-line of the base of support more than the control subjects, however the deviation was not always towards the unaffected leg. Compared to control subjects the stroke patients had significant deficits in the ability to weight-shift in the lateral direction to both legs. Although the stroke patients showed a trend for less displacement to the affected leg than the unaffected leg, this difference was not greater than the comparable difference in control subjects. The true ability to weight-shift to the unaffected leg may have been masked because of the testing protocol. For this reason modifications are required to the testing protocol. These findings from stroke patients in the early stage post-onset provide objective data on which to base treatment strategies during rehabilitation.

The relationship of isometric strength to peak dynamic hand forces during submaximal weight lifting

Abstract Reports have indicated that approximately one third of the US workforce is presently required to exert significant strength as part of their jobs. In addressing the prevention of these types of injuries, the assessment of muscular strength can provide a method of predicting whether a person is capable of performing the job without incurring injury. Currently, isometric strength assessments are often used to assist in predicting the capability to safely perform a lifting task. However, given the dynamic nature of work activities, isometric values may be limited, particularly if the load is well below a persons strength capability. Thus, it is of interest to evaluate the relationship between isometric strength values and peak dynamic hand forces under varied submaximal loading. It is shown in this study that the peak hand forces, exhibited while dynamically lifting different submaximal loads, are not highly correlated with a persons isometric lifting strength in similar postures. It is also shown that for very light load lifting, the peak accelerations approached 2.5 gs, further supporting the need to limit such lifting from floor level by using ergonomic interventions.

Looptraining met behulp van de tredmolen na een femurhalsfractuur

Het resultaat van de revalidatie via twee verschillende methoden van looptraining werd onderzocht bij 40 oudere vrouwelijke patienten die een femurhalsfractuur hadden ondergaan. Twintig patienten in een controlegroep kregen de conventionele looptraining, twintig andere patienten deden mee in een experimentele groep waarin de looptraining met behulp van een tredmolen werd gegeven. Het resultaat van de revalidatie werd gedefinieerd door tijd-ruimtelijke parameters van het looppatroon en door het niveau van de mobiliteit van de patient (aan huis gebonden, beperkt of onbeperkt). Tevens werden de spierkracht en de bewegingsuitslag in de onderste extremiteit gemeten.