![]() Despite extensive literature showing microstructural damage in the CST of children with HCP ( Scheck et al., 2012), little is known about how the underlying lesion affects the maturation process of these fibers.ĬST maturation is a complex process affected by dynamic factors such as synaptic pruning and development ( Eyre et al., 2001), myelination ( Eyre et al., 1991), changes in axonal diameter and length ( Eyre et al., 2002) and organization of pyramidal neuron firing patterns ( Chiappa et al., 1991). This lesion impairs the structural integrity of the corticospinal tracts (CST), which are the most important tracts for fine motor skills, and among the first tracts to mature. The underlying etiology is a non-progressive lesion located most commonly in the periventricular white matter of the developing fetal or infant brain ( Rosenbaum et al., 2007). Children with HCP reliably exhibit prominent impairment in skilled voluntary movements. ![]() Hemiplegic cerebral palsy (HCP) is a common subtype of motor dysfunction, affecting one-third of patients with a clinical cerebral palsy diagnosis ( Hagberg et al., 2001). – Absent resting motor threshold maturational trajectory in the more affected hemisphere of children with HCP Introduction – Preserved resting motor threshold maturational trajectory in the less affected hemisphere of children with HCP – Halted bilateral corticospinal tracts imaging metrics maturation in children with HCP – Linear age-dependent developmental trajectories of corticospinal tracts diffusion metrics Additionally, the TMS-derived previously established rMT developmental trajectory was preserved in the LA hemisphere of children with HCP ( n = 26 p < 0.0001) but this trajectory was absent in the MA hemisphere.Ĭonclusions: Corticospinal tract maturation arrests in both hemispheres of children with HCP, possibly reflecting perinatal disruption of corticospinal tract myelination and axonal integrity. ![]() This maturation process was absent in both MA and LA hemispheres of children with HCP. Results: We observed a significant AD and MD developmental trajectory, both of which were inversely related to age (decrease in AD and diffusivity corresponding to increased age) in both hemispheres of TD children ( p < 0.001). Resting motor threshold (rMT) was obtained per hemisphere, per patient. Transcranial magnetic stimulation (TMS) was performed as a neurophysiologic measure of corticospinal tract integrity and organization. With diffusion tensor imaging (DTI), we estimated the mean fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) of the corticospinal tract, parameters indicative of factors including myelination and axon density. Methods: Neuroimaging data were obtained from 36 children with HCP for both the more affected (MA) and less affected (LA) hemispheres, and, for purposes of direct comparison, between groups, 15 typically developing (TD) children. 7Department of Neurology, Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, United StatesĪim: To assess changes in the developmental trajectory of corticospinal tracts (CST) maturation in children with hemiplegic cerebral palsy (HCP).6Department of Radiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States.5Department of Orthopedic Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA, United States
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