Human lower leg muscles grow asynchronously.

Muscle volume must increase substantially during childhood growth to generate the power required to propel the growing body. One unresolved but fundamental question about childhood muscle growth is whether muscles grow at equal rates; that is, if muscles grow in synchrony with each other. In this study, we used magnetic resonance imaging (MRI) and advances in artificial intelligence methods (deep learning) for medical image segmentation to investigate whether human lower leg muscles grow in synchrony. Muscle volumes were measured in 10 lower leg muscles in 208 typically developing children (eight infants aged less than 3 months and 200 children aged 5 to 15 years). We tested the hypothesis that human lower leg muscles grow synchronously by investigating whether the volume of individual lower leg muscles, expressed as a proportion of total lower leg muscle volume, remains constant with age. There were substantial age-related changes in the relative volume of most muscles in both boys and girls (p < 0.001). This was most evident between birth and five years of age but was still evident after five years. The medial gastrocnemius and soleus muscles, the largest muscles in infancy, grew faster than other muscles in the first five years. The findings demonstrate that muscles in the human lower leg grow asynchronously. This finding may assist early detection of atypical growth and allow targeted muscle-specific interventions to improve the quality of life, particularly for children with neuromotor conditions such as cerebral palsy.

Living with Loss: study protocol for a randomized controlled trial evaluating an internet-based perinatal bereavement program for parents following stillbirth and neonatal death.

BACKGROUND: Stillbirth and neonatal death are devastating pregnancy outcomes with long-lasting psychosocial consequences for parents and families, and wide-ranging economic impacts on health systems and society. It is essential that parents and families have access to appropriate support, yet services are often limited. Internet-based programs may provide another option of psychosocial support for parents following the death of a baby. We aim to evaluate the efficacy and acceptability of a self-guided internet-based perinatal bereavement support program "Living with Loss" (LWL) in reducing psychological distress and improving the wellbeing of parents following stillbirth or neonatal death. METHODS: This trial is a two-arm parallel group randomized controlled trial comparing the intervention arm (LWL) with a care as usual control arm (CAU). We anticipate recruiting 150 women and men across Australia who have experienced a stillbirth or neonatal death in the past 2 years. Participants randomized to the LWL group will receive the six-module internet-based program over 8 weeks including automated email notifications and reminders. Baseline, post-intervention, and 3-month follow-up assessments will be conducted to assess primary and secondary outcomes for both arms. The primary outcome will be the change in Kessler Psychological Distress Scale (K10) scores from baseline to 3-month follow-up. Secondary outcomes include perinatal grief, anxiety, depression, quality of life, program satisfaction and acceptability, and cost-effectiveness. Analysis will use intention-to-treat linear mixed models to examine psychological distress symptom scores at 3-month follow-up. Subgroup analyses by severity of symptoms at baseline will be undertaken. DISCUSSION: The LWL program aims to provide an evidence-based accessible and flexible support option for bereaved parents following stillbirth or neonatal death. This may be particularly useful for parents and healthcare professionals residing in rural regions where services and supports are limited. This RCT seeks to provide evidence of the efficacy, acceptability, and cost-effectiveness of the LWL program and contribute to our understanding of the role digital services may play in addressing the gap in the availability of specific bereavement support resources for parents following the death of a baby, particularly for men. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12621000631808 . Registered prospectively on 27 May 2021.

Intramuscular fat in children with unilateral cerebral palsy.

BACKGROUND: Many children with cerebral palsy develop muscle contractures. The mechanisms of contracture are not well understood. We investigated the possibility that, because fat is stiffer than passive muscle, elevated intramuscular fat contributes to contracture. In this cross-sectional study, we compared the quantity and distribution of intramuscular fat in muscles from typically developing children and children with cerebral palsy who have contractures. METHODS: mDixon magnetic resonance images were obtained from the legs of 20 ambulant children with unilateral spastic cerebral palsy who had ankle contractures (mean age 11 SD 3 years, 13 male, mean moderate level contracture) and 20 typically developing children (mean age 11 SD 4 years, 13 male). The images were analyzed to quantify the intramuscular fat fraction of the medial gastrocnemius muscles. The amount and distribution of intramuscular fat were compared between muscles of children with cerebral palsy and typically developing children. FINDINGS: In typically developing children, the medial gastrocnemius muscles had a mean intramuscular fat fraction of 4.7% (SD 1.6%). In children with cerebral palsy, the mean intramuscular fat fractions in the more- and less-affected medial gastrocnemius muscle were 11.4% (8.1%) and 6.9% (3.4%) respectively. There were small but statistically significant regional differences in the distribution of intramuscular fat. There was no evidence of a relationship between intramuscular fat fraction and severity of contracture. INTERPRETATION: Children with cerebral palsy have higher proportions of intramuscular fat than typically developing children. There is no clear relationship between intramuscular fat fraction and dorsiflexion range of motion in children with cerebral palsy.

Muscle architecture in children with cerebral palsy and ankle contractures: an investigation using diffusion tensor imaging.

BACKGROUND: Children with cerebral palsy frequently have ankle contractures which may be caused by changes in architecture of calf muscles. Here, we compared the architecture of medial gastrocnemius muscles in children with unilateral cerebral palsy and typically developing children using novel imaging techniques. METHODS AND PROCEDURES: Muscle volumes, fascicle lengths, pennation angles and physiological cross-sectional areas were measured from diffusion tensor images and mDixon scans obtained from 20 ambulant children with unilateral spastic cerebral palsy who had ankle contractures (age 11 ±â€¯3 years; mean ±â€¯standard deviation) and 20 typically developing children (11 ±â€¯4 years). FINDINGS: In children with cerebral palsy, the more-affected side had, on average, 13° less dorsiflexion range and the medial gastrocnemius muscle had 4.9 mm shorter fascicles, 50 cm3 smaller volume and 9.5 cm2 smaller physiological cross-sectional area than the less-affected side. Compared to typically developing children, the more-affected side had 10° less dorsiflexion range and the medial gastrocnemius muscle had 4.2 mm shorter fascicles, 51 cm3 smaller volume and 10 cm2 smaller physiological cross-sectional area. We did not detect differences between the less-affected and typically developing legs. INTERPRETATION: Three-dimensional measurement of whole medial gastrocnemius muscles confirmed that the architecture of muscles on the more-affected side of children with cerebral palsy differs from the less-affected side and from muscles of typically developing children. Reductions in fascicle length, muscle volume and physiological cross-sectional area may contribute to muscle contracture.

Electrical Stimulation Following Botulinum Toxin A in Children With Spastic Diplegia: A Within-Participant Randomized Pilot Study.

AIMS: To determine whether electrical stimulation (ES) following botulinum toxin A (BoNT/A) injection increases passive extensibility of the hamstring muscles in children with spastic diplegia. METHODS: Six children undergoing bilateral BoNT/A injections to the hamstrings participated in this within-participant single blind randomized controlled trial. One leg of each child was randomised to the experimental condition and the other to the control condition. The experimental leg received daily stretch and ES to the hamstrings for 12 weeks, while the control leg received only daily stretch. The primary outcome was passive hamstring extensibility reflected by popliteal angle measured with a standardised torque. Secondary outcomes were two goniometric measures of popliteal angle using the Modified Tardieu Scale (R1 and R2), and parents' perceptions of treatment effectiveness. Outcomes were measured at baseline, 4 weeks, 12 weeks and 6 months. RESULTS: The mean between-group difference (95% CI) at 4 weeks was 2° (-2 to 5) for popliteal angle measured with a standardised torque, favouring the experimental leg. Tardieu results for R1 and R2 were 0° (-4 to 3) and 7° (0 to 14), respectively. CONCLUSION: ES does not improve passive extensibility of the hamstring muscles at 4 weeks over any possible effects of BoNT/A alone.

Hip displacement in spastic cerebral palsy: repeatability of radiologic measurement.

Radiologic measures of migration percentage (MP) and acetabular index (AI) taken from plain radiographs of the pelvis are the most commonly used tools for determining hip displacement and management options in children with cerebral palsy and spastic hip disease. This study determined interrater and intrarater reliability of MP and AI on pelvic radiographs chosen to represent a wide range of age (11 months to 8 years 5 months), MP (0%-56%), and AI (9 degrees -33 degrees ). The study demonstrated that an experienced rater would be expected to measure MP on a single radiograph to within +/-5.8% of the true value and a change in MP between two radiographs taken at different times to within +/-8.3% of the true value. Similarly for AI, the measurement error for a typical rater would be within +/-2.6 degrees on a single reading and +/-3.7 degrees if recording change between two occasions. The authors believe that the results indicating true change are acceptable in clinical practice, provided treatment decisions are based on a series of radiographs taken at 6-month intervals, methods and training are standardized, and consistent raters are used.