Relationship between brain structure and function in children with cerebral visual impairment and cerebral palsy

Abstract

Objective: To examine the relationship between brain structure and function in children with cerebral visual impairment (CVI) and cerebral palsy (CP). Design: A cross-sectional study. Method: Children, aged three months to ≤14 years with, or at high risk of, CP or neurodevelopmental delay and a clinical MRI already performed were recruited. All children enrolled underwent a complete ophthalmology examination such as visual acuity, refraction and dilated fundus examination. Visuo-perceptual assessment included visual attention, clutter and recognition. The location, extent and presumed timing of the brain lesions were assessed using a semi-quantitative Fiori magnetic resonance imaging (MRI) scale and qualitative Krageloh Mann Classifications. Automated segmentation algorithms, to understand the quantitative relationship between the brain lesion (segmented volumes, cortical thickness) and CVI and CP were assessed. Results: 71 children, M:F = 1.8:1, age range eight months-13.4 years, GMFCS I = 18, II = 14, III = 7, IV = 15, V = 15 were included in the study. Children were classified as bilateral CP, n = 49 (66%). The Fiori Global score of brain lesion severity was correlated with clinical structural MRI (r = 0.3, p = 0.01, 95% CI = 0.07-0.50). Classification of CVI was not significantly associated with GMFCS (suspected CVI, median [IQR] = 4 [1.25-4]; and definite CVI, median [IQR] = 2 [1-4], p = 0.07).There was insufficient evidence to suggest an association between Fiori Global score and CVI patterns (purely dorsal and mixed) where purely dorsal CVI, (median [IQR] = 10 [0-19.5]) and mixed CVI (median [IQR] = 8.5 [6.5-21.5] p = 0.08). There is an association between Krageloh Mann brain lesion (type) classification and patterns of CVI where purely dorsal CVI [median (IQR) = 2 (2-3), mixed CVI [median (IQR) = 2 (0-2) p = 0.01] with periventricular brain lesions most seen in children with dorsal stream dysfunction. On the laterality index based on Fiori scoring of the MRI, among the unilateral CP n = 22 (31%), bilateral lesions were seen in five participants. Mixed type of CVI pattern was seen in 18 cases of which 10 had the entire ventral and dorsal streams involved. Conclusion: In our selected cohort all children with CP showed evidence of CVI which varied in its clinical presentation. Only 85 percent demonstrated a brain lesion accounting for both the motor and visual impairment. This study highlights the importance to understand the relationship of brain lesions, its severity, extent, location, presumed timing of injury on vision and visual behaviour. Determining these relationships enable recognition of visuo-perceptual dysfunction to inform rehabilitation strategies. This is the first study to validate the Fiori brain lesion severity scale in children with CVI and CP.L6381698972022-06-10 <br />