Mitell Sison-Williamson

Relationship of strength, weight, age, and function in ambulatory children with cerebral palsy

Background: The natural history of ambulatory function in individuals with cerebral palsy (CP) consists of deterioration over time. This is thought to be due, in part, to the relationship between strength and weight, which is postulated to become less favorable for ambulation with age. Methods: The study design was prospective, case series of 255 subjects, aged 8 to 19 years, with diplegic type of CP. The data analyzed for the study were cross-sectional. Linear regression was used to predict the rate of change in lower extremity muscle strength, body weight, and strength normalized to weight (STR-N) with age. The cohort was analyzed as a whole and in groups based on functional impairment as reflected by Gross Motor Function Classification System (GMFCS) level. Results: Strength increased significantly over time for the entire cohort at a rate of 20.83 N/y (P=0.01). Weight increased significantly over time for the entire cohort at a rate of 3.5 kg/y (P<0.0001). Lower extremity STR-N decreased significantly over time for the entire cohort at a rate of 0.84 N/kg/y (P<0.0001). The rate of decline in STR-N (N/kg/y) was comparable among age groups of the children in the study group. There were no significant differences in the rate of decline of STR-N (N/kg/y) among GMFCS levels. There was a 90% chance of independent ambulation (GMFCS levels I and II) when STR-N was 21 N/kg (49% predicted relative to typically developing children). Discussion: The results of this study support the longstanding clinically based observation that STR-N decreases with age in children with CP. This decrease occurs throughout the growing years, and across GMFCS levels I to III. Independent ambulation becomes less likely as STR-N decreases. This information can be used to support the rationale, and provide guidelines, for a range of interventions designed to promote ambulation in children with CP.

Biceps Brachii Long Head Overactivity Associated with Elbow Flexion Contracture in Brachial Plexus Birth Palsy

BACKGROUND The etiology of elbow flexion contracture in children with brachial plexus birth palsy remains unclear. We hypothesized that the long head of the biceps brachii muscle assists with shoulder stabilization in children with brachial plexus birth palsy and that overactivity of the long head during elbow and shoulder activity is associated with an elbow flexion contracture. METHODS Twenty-one patients with brachial plexus birth palsy-associated elbow flexion contracture underwent testing with surface electromyography. Twelve patients underwent repeat testing with fine-wire electromyography. Surface electrodes were placed on the muscle belly, and fine-wire electrodes were inserted bilaterally into the long and short heads of the biceps brachii. Patients were asked to perform four upper extremity tasks: elbow flexion-extension, hand to head, high reach, and overhead ball throw. The mean duration of muscle activity in the affected limb was compared with that in the contralateral, unaffected limb, which was used as a control. Three-dimensional motion analysis, surface dynamometry, and validated function measures were used to evaluate upper extremity kinematics, elbow flexor-extensor muscle imbalance, and function. RESULTS The mean activity duration of the long head of the biceps brachii muscle was significantly higher in the affected limb as compared with the contralateral, unaffected limb during hand-to-head tasks (p = 0.02) and high-reach tasks (p = 0.03). No significant differences in mean activity duration were observed for the short head of the biceps brachii muscle between the affected and unaffected limbs. Isometric strength of elbow flexion was not significantly higher than that of elbow extension in the affected limb (p = 0.11). CONCLUSIONS Overactivity of the long head of the biceps brachii muscle is associated with and may contribute to the development of elbow flexion contracture in children with brachial plexus birth palsy. Elbow flexion contracture may not be associated with an elbow flexor-extensor muscle imbalance, as previously hypothesized. The negative impact of elbow flexion contracture on upper extremity function warrants future research in the development of preventive and therapeutic techniques to address elbow flexion contractures in children with brachial plexus birth palsy.

The validity of compliance monitors to assess wearing time of thoracic-lumbar-sacral orthoses in children with spinal cord injury.

Study Design. Prospective multicenter observation. Objective. To determine the validity of 3 commercially available at recording thoracic-lumbar-sacral orthosis (TLSO) wearing time of children with spinal cord injury (SCI) and to assess each monitors function during daily activities. Summary of Background Data. A major limitation to studies assessing the effectiveness of spinal prophylactic bracing is the patients compliance with the prescribed wearing time. Although some studies have begun to use objective compliance monitors, there is little documentation of the validity of the monitors during activities of daily life and no comparisons of available monitors. Methods. Fifteen children with SCI who wore a TLSO for paralytic scoliosis were observed for 4 days during their rehabilitation stay. Three compliance monitors (2 temperature and 1 pressure sensitive) were mounted onto each TLSO. Time of brace wear from the monitors was compared with the wear time per day recorded in diaries. Results. Observed versus monitored duration of brace wear found the HOBO (temperature sensitive) to be the most valid compliance monitor. The HOBO had the lowest average of difference and variance of difference scores. The correlation between the recorded daily entries and monitored brace wear time was also highest for the HOBO in analysis of dependent and independent scores. Bland-Altman plots showed that the pressure sensitive monitor underestimated wear time whereas the temperature monitors overestimated wear time. Conclusion. Compliance to prescribed wearing schedule has been a barrier to studying TLSO efficacy. All 3 monitors were found to measure TLSO compliance, but the 2 temperature monitors were more in agreement with the daily diaries. Based on its functional advantages compared with the HOBO, the StowAway TidbiT will be used to further investigate the long-term compliance of TLSO bracing in children with SCI.

Effect of thoracolumbosacral orthoses on reachable workspace volumes in children with spinal cord injury.

Abstract Background/Objective: Wheelchair users often use trunk motion to facilitate or augment their upper extremity reach. Children with spinal cord injury (SCI) are often prescribed thoracic lumbar sacral orthoses (TLSO) to delay or prevent spinal curve progression. The impact of wearing a TLSO while reaching has not been studied. Therefore, the purpose of this study was to see the quantitative effect of the TLSO on reachable workspace volumes and reach of children with SCI. Methods: Twenty children with SCI aged 5 to 18 years participated in the present study. Three-dimensional upper extremity motion analysis was used to assess the reachable workspace patterns of children reaching for targets at varying heights. Volumes in and out of TLSO and kinematic ranges of reach were statistically analyzed using paired Student’s t tests with a P value set at 0.05. Results: Reachable workspace volumes were significantly greater for the non-TLSO condition compared with the TLSO condition (112,836 vs 80,711 cm3; P = 0.0002; a decrement of 28%). Anterior posterior and medial lateral ranges of reach were statistically greater in the non-TLSO condition (P = 0.002, P = 0.01 ). Nondominant hand medial lateral reaches were statistically greater in the non-TLSO condition (P = 0.003). Dominant hand anterior posterior reaches were greater in the non-TLSO condition (P = 0.009). Conclusions: Results suggest the reachable workspace of children with SCI is lessened with the use of a TLSO. This may be an important negative factor for brace compliance in children with SCI. The TLSO interferes with their ability to reach; therefore, children may prefer not to wear the orthosis.

Analysis of upper extremity motion in children after axillary burn scar contracture release.

Burns to the upper extremity and axilla frequently result in the formation of contractures that can impede shoulder range of motion. The purpose of this study was to determine the long-term effects of upper extremity burn scar contracture release on motion during activities of daily living in the first year postrelease. Upper extremity motion analysis was conducted on children aged 4 to 17 years before and 1, 3, 6, and 12 months after axillary contracture release surgery. Movements were analyzed during three functional tasks including high reach (reaching for an object), hand to head (combing hair), and hand to back pocket (toileting). A total of 23 subjects (34 axillary contractures; mean age 10 ± 3 years; mean TBSA burn 40 ± 6%) completed the study. Preoperatively, decreased shoulder mobility due to axillary contractures resulted in the use of compensatory motions to complete the tested activities. Surgical release of the contracture increased shoulder mobility and decreased compensatory movements. Improvements were maintained for 1 year after surgery with majority of the improvement involving shoulder flexion. Axillary contracture release surgery improves functional shoulder mobility and decreases compensatory motions used during activities of daily living in the first year postrelease. Additional follow-up is needed to evaluate the impact of growth on scar development.

Long-term postoperative outcomes after axillary contracture release in children with burns

Children with upper extremity burns frequently develop axillary contractures that can restrict movement. Surgical axillary contracture release is performed to restore function. The purpose of this study is to determine the long-term effects (up to 7 years) of surgical axillary contracture release on upper extremity motion during simulated activities of daily living using three-dimensional motion analysis. Motion analysis was conducted on 10 subjects (9 males and 1 female; 16 axillary contractures; mean age 10 ± 3 years at baseline; mean TBSA burn 40 ± 15%) before, 1 year after, and 2 to 7 years (mean 3 ± 2 years) after axillary contracture release with split-thickness skin graft surgery. Movements were analyzed during three functional tasks including high reach (reaching overhead for an object), hand to head (combing hair), and hand to back pocket (toileting). Two-tailed paired t-tests were used to compare presurgical and postsurgical scores. Surgical release of the axillary contracture increased shoulder mobility and decreased compensatory movements. Improvements were maintained at long-term follow-up. All shoulder movements with the exception of shoulder flexion during the high reach task and shoulder abduction during the hand to back task were not significantly different than normal values at long-term follow-up. Axillary contracture release surgery improves shoulder function in the short and long term. Motion analysis is a modality that may prove valuable in objectively quantifying changes in movement patterns immediately and in subsequent years after burn injury.

Hip kinetics during gait are clinically meaningful outcomes in young boys with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked genetic neuromuscular disorder characterized by progressive proximal to distal muscle weakness. The success of randomized clinical trials for novel therapeutics depends on outcome measurements that are sensitive to change. As the development of motor skills may lead to functional improvements in young boys with DMD, their inclusion may potentially confound clinical trials. Three-dimensional gait analysis is an under-utilized approach that can quantify joint moments and powers, which reflect functional muscle strength. In this study, gait kinetics, kinematics, spatial-temporal parameters, and timed functional tests were quantified over a one-year period for 21 boys between 4 and 8 years old who were enrolled in a multisite natural history study. At baseline, hip moments and powers were inadequate. Between the two visits, 12 boys began a corticosteroid regimen (mean duration 10.8±2.4 months) while 9 boys remained steroid-naïve. Significant between-group differences favoring steroid use were found for primary kinetic outcomes (peak hip extensor moments (p=.007), duration of hip extensor moments (p=.007), peak hip power generation (p=.028)), and spatial-temporal parameters (walking speed (p=.016) and cadence (p=.021)). Significant between-group differences were not found for kinematics or timed functional tests with the exception of the 10m walk test (p=.03), which improves in typically developing children within this age range. These results indicate that hip joint kinetics can be used to identify weakness in young boys with DMD and are sensitive to corticosteroid intervention. Inclusion of gait analysis may enhance detection of a treatment effect in clinical trials particularly for young boys with more preserved muscle function.

Variation in kinematic and spatiotemporal gait parameters by Gross Motor Function Classification System level in children and adolescents with cerebral palsy

The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters in ambulatory children and adolescents with bilateral spastic cerebral palsy (BSCP) among Gross Motor Function Classification System (GMFCS) levels I‐III.

Variability explained by strength, body composition and gait impairment in activity and participation measures for children with cerebral palsy: a multicentre study

Objective: To determine the amount of variability in scores on activity and participation measures used to assess ambulatory individuals with cerebral palsy explained by strength, body composition, gait impairment and participant characteristics. Design: Multicentre prospective cross-sectional study. Setting: Seven paediatric–orthopaedic specialty hospitals. Participants: Three hundred and seventy-seven ambulatory individuals (241 males, 136 females) with cerebral palsy, Gross Motor Function Classification System (GMFCS) levels I–III (I = 148, II = 153, III = 76), ages 8–18 years (mean 12 years 9 months, SD 2 years 8 months). Methods: Participants completed assessments of GMFCS level, patient history, lower extremity muscle strength, Gross Motor Function Measure (GMFM-66), Pediatric Outcomes Data Collection Instrument (PODCI), instrumented gait analysis, 1 minute walk test, Timed Up-and-Go and body composition. Multiple linear regression and bootstrap analyses were performed for each outcome measure, stratified by GMFCS level. Results: The amount of variability in outcome measures explained by participant characteristics, strength, and gait impairment ranged from 11% to 50%. Gait impairment was the most common predictor variable and frequently explained the greatest variance across all outcome measures and GMFCS levels. As gait impairment increased, scores on outcome measures decreased. Strength findings were inconsistent and not a primary factor. Body composition contributed minimally (<4%) in explaining variability. Participant characteristics (cerebral palsy type, gestational age and age at walking onset), were significant predictor variables in several models. Conclusions: Variability in outcome measure scores is multifaceted and only partially explained by strength and gait impairment illustrating the challenges of attempting to explain variation within this heterogeneous population. Clinicians treating individuals with cerebral palsy should consider this when developing treatment paradigms.

Analysis of the relationships that body composition and muscular strength have with oxygen cost of walking in children with cerebral palsy

OBJECTIVE To investigate whether body composition and lower extremity strength relate to oxygen cost of walking in children with cerebral palsy (CP), and to evaluate the relative contributions of these measures to explain variation in oxygen cost seen in this population. METHODS A total of 116 children with spastic diplegic CP, Gross Motor Function Classification System levels I-III, aged 8-18 participated. Strength, body composition (body mass index (BMI) and percent body fat) and oxygen cost were recorded. Pearson correlations assessed relationships between variables of body composition and strength to oxygen cost. Forward stepwise linear regression analyzed variance explained by strength and body composition measures. Oxygen data were analyzed by weight status classifications using one-way analysis of variance with significance set at p<0.05. RESULTS Total strength (r=-0.27) and total extensor strength (r=-0.27) had fair inverse relationships with oxygen cost. Total extensor strength explained 7.5% (r(2)=0.075, beta=-0.274, p<0.01) of the variance in oxygen cost. Body composition did not explain significant variance in oxygen cost, however significant differences were found in oxygen consumption (p=0.003) and walking velocity (p=0.042) based on BMI weight classifications. CONCLUSIONS For ambulatory children with CP, oxygen cost during walking can be partially explained by total extensor strength and not body composition. However, those categorized as obese may adjust to a slower walking speed to keep their oxygen cost sustainable, which may further affect their ability to keep up with typically developing peers and possibly lead to greater fatigue.