Evaluation of an activity monitor for the objective measurement of free-living physical activity in children with cerebral palsy.

OBJECTIVE: To explore the use of an activity monitor (AM) to objectively characterize free-living physical activity (F-LPA) in children with mobility impairment resulting from cerebral palsy (CP). DESIGN: First, a validation study compared outcomes from the AM with video evidence. Second, multiday F-LPA was characterized. Relationships between laboratory measures and F-LPA were explored. SETTING: The evaluation study was conducted in a laboratory environment. F-LPA monitoring was conducted in the participants' free-living environment. PARTICIPANTS: Convenience sample of ambulatory children (N=15; 11 boys, 4 girls) aged 5 to 17 years with CP undergoing gait analysis. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Accuracy of the AM for sitting/lying time, upright time, stepping time, and strides taken. Daily volumes of F-LPA of children with CP. RESULTS: AM outcomes in comparison with video-based analysis were (mean ± SD) 97.4%±2.7%, 101.1%±1.5%, 99.5%±6.6%, 105.6%±15.8%, and 103.8%±10.1% for sitting/lying time, upright time, standing time, stepping time, and stride count, respectively. Participants' daily F-LPA demonstrated considerable variation: mean standing time ± SD, 2.33±.96h/d; mean stepping time ± SD, 1.68±.86h/d; mean steps per day ± SD, 8477±4528; and mean sit-to-stand transitions per day ± SD, 76±49. Laboratory-measured cadence and mobility level were related to F-LPA, but not directly. CONCLUSIONS: The AM demonstrated excellent ability to determine sitting/lying and upright times in children with CP. Stepping time and stride count had lower levels of agreement with video-based analysis but were comparable to findings in previous studies. Crouch gait and toe walking had an adverse effect on outcomes. The F-LPA data provided additional information on children's performance not related to laboratory measures, demonstrating the added value of using this objective measurement technique.

Repeatability of a new observational gait score for unilateral lower limb amputees.

The aim of this study was to assess the repeatability of an observational gait analysis score that was developed specifically for unilateral amputees. Ten videotaped sequences were analysed by six experienced observers on two separate occasions. Data were analysed using percentage agreement, the kappa statistic and the coefficient of repeatability. The score demonstrated good intraobserver repeatability with an average repeatability coefficient of 3 (range 1.5-4.6). Interobserver repeatability was poor with a repeatability coefficient of 5.9. This score could be used in practice to assess amputees and is most repeatable if used by the same observer to evaluate changes in patients over time.

Development of temporal and distance parameters of gait in normal children.

Temporal and distance parameters of 33 normal children were obtained from instrumented gait analysis prospectively over five consecutive years. The parameters were normalised to minimise the confounding effects of increasing height and leg length. Rank correlations were performed on normalised speed, normalised stride length, normalised cadence and normalised walk ratio across consecutive pairs of years to examine the ranking of these parameters for an individual child over time. Consistent trends of increasing rank correlation were observed in normalised stride length and normalised walk ratio suggesting that individual children were continuing to adjust these gait parameters towards their own characteristic position within the normal range. Consistent trends were not observed in the rank correlations for normalised speed and normalised cadence. These findings support the concept that individual children predominantly adjusted their cadence to effect changes in speed, while the development of stride length was dictated by other factors specific to the individual child. Rank correlation coefficients for walk ratio between consecutive years increased from the ages of 7-11 years of age and hence walk ratio appears be a feature of gait that matures beyond the age of 7 years. This accords with the proposal that it is an invariant parameter for an individual.