Corticospinal tract diffusion properties and robotic visually guided reaching in children with hemiparetic cerebral palsy

Abstract

Perinatal stroke is the leading cause of hemiparetic cerebral palsy (CP), resulting in life-long disability. In this study, we examined the relationship between robotic upper extremity motor impairment and corticospinal tract (CST) diffusion properties. Thirty-three children with unilateral perinatal ischemic stroke (17 arterial, 16 venous) and hemiparesis were recruited from a population-based research cohort. Bilateral CSTs were defined using diffusion tensor imaging (DTI) and four diffusion metrics were quantified: fractional anisotropy (FA), mean (MD), radial (RD), and axial (AD) diffusivities. Participants completed a visually guided reaching task using the KINARM robot to define 10 movement parameters including movement time and maximum speed. Twenty-six typically developing children underwent the same evaluations. Partial correlations assessed the relationship between robotic reaching and CST diffusion parameters. All diffusion properties of the lesioned CST differed from controls in the arterial group, whereas only FA was reduced in the venous group. Non-lesioned CST diffusion measures were similar between stroke groups and controls. Both stroke groups demonstrated impaired reaching performance. Multiple reaching parameters of the affected limb correlated with lesioned CST diffusion properties. Lower FA and higher MD were associated with greater movement time. Few correlations were observed between non-lesioned CST diffusion and unaffected limb function though FA was associated with reaction time (R = -0.39, p < .01). Diffusion properties of the lesioned CST are altered after perinatal stroke, the degree of which correlates with specific elements of visually guided reaching performance, suggesting specific relevance of CST structural connectivity to clinical motor function in hemiparetic children.

Neurite orientation dispersion and density imaging quantifies corticospinal tract microstructural organization in children with unilateral cerebral palsy

“…Perinatal stroke disrupts typical CST development through neuronal cell loss, axonal degeneration and demyelination processes, all of which lead to motor impairment. Prior DWI studies have demonstrated greater diffusivity in the lesioned CST after perinatal stroke in children with UCP (Hodge et al, ; Kuczynski et al, ; Kuo et al, ; Manning et al, ; Weinstein et al, ). We have confirmed these results for three tensor‐based measures: MD, AD, and RD, which all showed significantly greater diffusivity in the lesioned compared to the nonlesioned CST.…”

“…However, we were unable to draw conclusions about CST microstructural organization across lesion subtypes due to the small sample size (Reid, Pagnozzi, et al, ). Recently, Kuczynski et al, () compared diffusion properties of the lesioned CST between children with arterial and venous infarctions, finding differences in MD, AD, and RD in the arterial but not the venous subgroup as compared to controls. Differentiating lesion phenotype in future DWI analyses may help identify subgroups of children with distinctive patterns of CST microstructural organization.…”

“…However, we were unable to draw conclusions about CST microstructural organization across lesion subtypes due to the small sample size (Reid, Pagnozzi, et al, 2017). Recently, Kuczynski et al, (2018) compared diffusion properties of the lesioned CST between children with arterial and venous infarctions, finding differences in MD, AD, Differences in parameter selection may also greatly impact the output of tractography, as highlighted in a recent animal study comparing a variety of tractography methods to histological tracers to characterize the anatomical accuracy of CST tractography (Schilling et al, 2018). Our tractography method is similar to the methods of Reid et al, 2016, but we also used different scan parameters and our own analysis approach which varied from other published studies in children with UCP.…”

Tractography-guided surgery of brain tumours: what is the best method to outline the corticospinal tract?

“…Thus, there is no universal tractographic approach to delineate the CST due to interference of other crossing fibre tracts (although it may be overcome when the CP or the PLIC stand as a single ROI) [15]. Some authors proposed using the CP and the PLIC as two ROI where all the fibres would run through [1,14]. At our institution we abandoned this technique and now use a custom DTI technique for all our patients because we believe that estimating the CST around the tumours at the eloquent cortex should utilize a variety of ROIs rather than a standardized a set due to several of the reasons indicated before.…”

“…After reviewing recent methods of DTI of the CST, we utilized two basic type of ROIs to outline the CST [1,[4][5][6]12,14,15]. Two main ROIs were designated as "start points": the cerebral peduncle (CP) and the posterior limb of internal capsule (PLIC).…”