Muscle activity during gait initiation in normal elderly people.

The purpose of this study was to describe the patterns of phasic muscle during gait initiation in normal elderly people. Bilateral surface EMG recordings were made of tibialis anterior, medial gastrocnemius and gluteus medius activity throughout gait initiation in 21 subjects. A variable expression of the onset muscle pattern is shown, with a tendency for muscle activity to be more variable in the preparatory phase. These results provide a baseline of normal gait initiation muscle activity against which to compare that of patients with gait initiation and balance difficulties.

A hypothesis: self-propulsion in a wheelchair early after stroke might not be harmful.

BACKGROUND: There is often strong clinical resistance to patients self-propelling a wheelchair post stroke as this is believed to produce immediate increases in abnormal posture and movement. Research to support this viewpoint is limited. OBJECTIVE: To begin investigation of the immediate effects of self-propulsion on symmetrical sitting. DESIGN: Replicated single-case studies ABABA. SETTING: Movement analysis laboratory. SUBJECTS: Four patients, a maximum of eight weeks post stroke and six age-matched healthy volunteers. INTERVENTIONS: Subjects sat in the wheelchair during the A phases and self-propelled forwards during the B phases. The Manchester Active Position Seat (consists of 68 force transducers which transmit data at 10 Hz) measured the magnitude of peak force and the position of peak force on both sides of the seat. The mean symmetry index and standard deviation for each study phase were calculated and graphed for each subject. Interpretation was by visual inspection. RESULTS: Only one stroke patient and one volunteer increased asymmetry of magnitude of peak force following the two periods of self-propulsion. Only one of the stroke patients increased asymmetry of position of peak force following self-propulsion compared with three of the healthy volunteers. CONCLUSIONS: These results raise the hypothesis that self-propulsion early post stroke might not produce immediate detrimental effects on seated symmetry.

Measurement of sitting balance using the Manchester Active Position Seat (MAPS): a feasibility study.

BACKGROUND: Evaluation of the effectiveness of therapy to improve sitting balance has been hampered by the limited number of sensitive objective clinical measures. We developed the Manchester Active Position Seat (MAPS) to provide a portable system to track change in the position of centre of force over time. OBJECTIVES: (1) To investigate whether there is correspondence between the measurement of position change by a forceplate and by MAPS. (2) To explore whether and how MAPS measures changes in position when seated healthy adults change posture. DESIGN: A feasibility study. METHODS: (1) An adult subject sat on MAPS placed on top of a forceplate. The x and y coordinates of the centre of pressure recorded from the forceplate and centre of force from MAPS during movement were compared graphically. (2) Four adults sat on MAPS using a standardized starting position and moving into six sets of six standardized target postures in a predetermined randomized order. The absolute shift in centre of force from the starting position was calculated. RESULTS: (1) The pattern of change of position over time was similar for the forceplate and for MAPS although there was a measurement difference, which increased with distance from the centre. (2) The direction of change of position corresponded to the direction of movement to the target postures but the amount of change varied between subjects. CONCLUSIONS: MAPS shows promise as an objective clinical measure of sitting balance, but peripheral accuracy of measurement needs to be improved.

Dual-task effects of talking while walking on velocity and balance following a stroke.

BACKGROUND: Therapists and nurses often use verbal instruction in the rehabilitation of mobility following stroke. This study aimed to determine whether performing a verbal cognitive task while walking adversely affected patients' balance and velocity. METHODS: There were two counterbalanced conditions: walking only and walking and concurrent cognitive activity. The cognitive activity used was to give one of two verbal responses to two verbal stimuli. An electronic GaitMat measured gait velocity and balance (double support time as a percentage of stride time). RESULTS: 11 people with stroke participated in the study (five women and six men, mean age 72 years, SD 9). They were on average 120 (SD 48) days post-stroke. Velocity decreased (P=0.017) and double-support time as a percentage of stride time increased (P=0.010) when the cognitive activity was added to the test. CONCLUSIONS: Performing a verbal cognitive task while walking adversely affected stroke patients' balance and gait velocity. Susceptibility to disruption varied within the patient group, suggesting clinical heterogeneity. Further research is required before changes to clinical practice are justified.

Conventional physiotherapy and treadmill re-training for higher-level gait disorders in cerebrovascular disease.

OBJECTIVES: to compare the therapeutic effects of two approaches to gait re-training--a schedule of conventional physiotherapy and treadmill re-training--in patients with higher-level gait disorders associated with cerebral multiinfarct states. DESIGN: single-blind crossover study involving a 4-week baseline period, 4 weeks of treadmill re-training and 4 weeks of conventional physiotherapy. SETTING: a large teaching hospital. SUBJECTS: patients with cerebral multi-infarct states who met the criteria for higher-level gait disorders. Computed tomographic brain scans showed at least one large vessel infarct, basal ganglia and white matter lacunes or extensive leukoaraiosis. INTERVENTIONS: a schedule of treadmill re-training and a specific schedule of physiotherapy containing 31 interventions in three treatment modules: (i) for gait ignition failure and turning; (ii) to improve postural alignment and enhance balance reactions; and (iii) for other components of cerebral multi-infarct state disordered gait. MAIN OUTCOME MEASURES: spatial and temporal gait measures and activity of daily living assessments. RESULTS: we recruited 18 patients, mean (SD) age 79.1 (6.8) years. Patients walked an average of 7.9 (5.5) km on the treadmill and had an average of 6.7 (3.2) h of physiotherapy. There were clinically moderate but highly statistically significant (P < 0.001) improvements in the following indices: time taken to complete the sit-to-stand test; time taken to walk 10 m; number of steps over 10 m; walking velocity; right and left step lengths; and time taken to complete the 'S' test. There were no differences in the results obtained in each limb of the study. CONCLUSION: there is no difference between the effects of conventional physiotherapy and treadmill re-training on the gait of patients with higher-level gait disorders associated with cerebral multi-infarct states. However, the improvements seen during the treatment period suggest that there is scope to improve the gait of this group of frail, elderly patients.

Validity and reliability of a kinematic protocol for determining foot contact events.

Timing of foot contact events provides important information for gait studies. The aim of the study is to validate the use of kinematic data, collected at 50 Hz to define foot contact events during gait initiation. Simultaneous kinetic and kinematic data recordings of four discrete foot contact events were made for normal adults. Raters were asked to estimate the timing of the events from kinematic data curves and these timings were compared with those derived from the kinetic data. For the four events, between 88 and 98% of all ratings were accurate to within 0.03 s. Inter-rater reliability was extremely high, reflecting the precision of the definitions used.