Microstructural changes in the spinal cord of adults with cerebral palsy

Abstract

Aim: To quantify the microstructural differences in the cervical-thoracic spinal cord of adults with cerebral palsy (CP).

Method: Magnetic resonance imaging of the proximal spinal cord (C6-T3) was conducted on a cohort of adults with CP (n=13; mean age=31y 11mo, standard deviation [SD] 8y 7mo; range=20y 8mo-47y 6mo; eight females, five males) and population norm adult controls (n=16; mean age=31y 4mo, SD 9y 9mo; range=19y 4mo-49y 5mo; seven females, nine males). The cross-sectional area (CSA) of the spinal cord, gray and white matter, magnetization transfer ratio (MTR), and fractional anisotropy of the cuneatus and corticospinal tracts were calculated.

Results: The total spinal cord CSA and proportion of the spinal cord gray matter CSA were significantly decreased in the adults with CP. The corticospinal tracts' MTR was lower in the adults with CP. Individuals that had reduced gray matter also tended to have reduced MTR in their corticospinal tracts (r=0.42, p=0.029) and worse hand dexterity clinical scores (r=0.53, p=0.004).

Interpretation: These results show that there are changes in the spinal cord microstructure of adults with CP. Ultimately, these microstructural changes play a role in the extent of the hand sensorimotor deficits seen in adults with CP. What this paper adds Adults with cerebral palsy (CP) have a reduced spinal cord cross-sectional area (CSA). Spinal cord gray matter is reduced in adults with CP. Spinal cord CSA is associated with hand dexterity. Magnetization transfer ratio of corticospinal tracts was lower in adults with CP.

Figure 1:

(a) The sagittal view of the cervical-thoracic spinal cord segmentation for a single representative adult with cerebral palsy (CP). (b) Parcellations of the cross-sectional area (CSA) from C6 to T3 for a representative adult participant with CP (left) and population norm adult control (right). The aqua represents white matter while the yellow represents gray matter. (c) Average spinal cord CSA for the adults with CP and adult controls. The CSA was significantly less for the adults with CP. (d) Average gray matter CSA for the adults with CP and adult controls. As shown, the CSA was significantly less for the adults with CP. (e) Average white matter CSA for the adults with CP and controls. The white matter CSA was also significantly less for the adults with CP. Bar graphs represent the mean and the standard error of the mean. ^ap≤0.05.

Figure 2:

(a) Example fractional anisotropy map from a representative participant. (b) Example magnetization transfer ratio images from a representative participant. The two images are from different participants.

Figure 3:

(a) The magnetization transfer ratio (MTR) in the corticospinal tracts for the adults with cerebral palsy (CP) and population norm adult controls. The adults with CP had significantly lower MTR in the corticospinal tracts, suggesting greater microstructural disruptions. (b) Scatter plot depicting the positive relationship between the corticospinal tract MTR and gray matter cross-sectional area (CSA). Adults with CP are depicted with white triangles, and the adult controls are depicted with black squares. Less gray matter was associated with a reduction in the corticospinal tract MTR, suggesting that participants with less grey matter CSA tended to have greater damage to the corticospinal tract microstructure. ^ap≤0.05. (c) Scatter plot depicting the relationship between the gray matter CSA and Box and Block Test scores. More gray matter was associated with improved hand dexterity.