This prospective, cross-sectional observational study aims to explore the relationship
between ultrasonographically assessed muscle morphology, functional muscle
characteristics, and standardized clinical parameters in ambulatory children diagnosed
with spastic cerebral palsy (CP). The research seeks to enhance the understanding of
muscle structure-function relationships in this population, with the broader goal of
contributing to personalized rehabilitation strategies and clinical decision-making.
Cerebral palsy is a non-progressive neurodevelopmental disorder resulting from brain
injury or maldevelopment during the prenatal, perinatal, or early postnatal period.
Spastic cerebral palsy is the most common subtype, characterized by upper motor neuron
lesions that lead to increased muscle tone, spasticity, and movement dysfunction. These
neuromuscular alterations often result in secondary changes in muscle morphology, such as
increased stiffness, reduced muscle volume, shortened fascicle length, altered fiber
orientation, and impaired microcirculation. Understanding how these changes relate to
functional limitations remains an important goal in pediatric rehabilitation research.
In this study, both structural and functional properties of skeletal muscles are planned
to be assessed using a combination of high-resolution ultrasound techniques. The targeted
muscles for assessment include one lower limb and one upper limb muscle: the medial
gastrocnemius and the brachialis. These muscles were selected due to their relevance in
gross motor and upper limb function in children with spastic CP.
The ultrasonographic parameters planned for evaluation include muscle thickness (MT),
fascicle length (FL), pennation angle (PA), cross-sectional area (CSA), and echo
intensity (EI). Additionally, muscle stiffness will be estimated through shear wave
elastography (SWE), and vascularity will be evaluated using superb microvascular imaging
(SMI) or a similar non-contrast-enhanced microvascular ultrasound technique. These
advanced imaging modalities allow for the assessment of tissue elasticity and
intramuscular blood flow, serving as potential surrogate markers of muscle quality and
pathology.
Measurements will be acquired under standardized conditions, with the muscles in a
relaxed state and proper anatomical alignment. Multiple images and repeated measurements
will be obtained to ensure consistency. Longitudinal and transverse imaging planes will
be used depending on the parameter being evaluated. The ultrasonographic protocol is
designed to minimize operator-dependent variability and to ensure reproducibility across
participants.
Clinical assessments will be conducted using standardized functional and
spasticity-related scales. Gross motor function will be evaluated using the Gross Motor
Function Classification System (GMFCS) and the Gross Motor Function Measure-66 (GMFM-66).
Hand function will be categorized using the Manual Ability Classification System (MACS).
Spasticity will be evaluated through the Modified Ashworth Scale (MAS) and the Tardieu
Scale, which include assessments of the angle of muscle reaction (R1), passive range of
motion (R2), and their difference (R2-R1). Where applicable, additional tools such as the
Assisting Hand Assessment (AHA) and the Observational Gait Scale (OGS) may be employed to
further characterize upper limb use and gait function.
Eligible participants include children aged 4 to 18 years with a diagnosis of spastic
cerebral palsy, classified within GMFCS levels I to III. Children with recent exposure to
interventions that could alter muscle morphology, such as botulinum toxin injection
(within 6 months) or orthopedic surgery, will be excluded. Other exclusion criteria
include the presence of non-spastic CP subtypes, neuromuscular disorders unrelated to CP,
or inability to cooperate with assessments. All assessments will be performed in a single
visit, without any therapeutic intervention being administered as part of the study.
The study involves no invasive procedures and is considered minimal risk. Its aim is
descriptive and correlational, without testing any treatment or hypothesis regarding
clinical efficacy. A power analysis was conducted to determine the required sample size
for detecting statistically significant correlations. Ethical approval has been obtained
from the relevant institutional ethics board. Data collected from participants will be
anonymized and managed according to institutional and national data protection
guidelines.
Planned statistical analyses include correlation coefficients between imaging parameters
and clinical scores, along with regression analyses to identify potential predictors of
motor function. Subgroup analyses may explore differences based on GMFCS level, age, or
previous therapy exposure. The findings may provide insights into the associations
between muscle architecture and clinical function in children with spastic CP,
contributing to the development of individualized rehabilitation protocols and improved
clinical monitoring.
