Cognitive strategies for locomotor navigation in normal development and cerebral palsy.

Visual-spatial impairment is a fundamental disorder in cerebral palsy (CP). However, current spatial testing is restricted to reaching space, whereas navigational space is seldom assessed. The Magic Carpet test, derived from the Corsi Block-tapping Task (CBT) for visual-spatial memory, is a new developmental test for navigation. The performances of the Magic Carpet test and CBT were assessed in 17 children with unilateral and bilateral spastic CP. The results were compared with an equal number of typically developing children, matched for age and sex. Magnetic resonance imaging scans of children with CP were scored according to a newly validated semi-quantitative classification. CBT span was significantly lower in CP, especially in bilateral forms, than in the comparison group, whereas the Magic Carpet test span did not significantly differ between the groups. CBT span, but not the Magic Carpet span, was related to gestational age at birth and to basic visual function. Both the CBT span and the Magic Carpet test were related to overall right-hemispheric impairment. In addition, CBT correlated with right periventricular impairment. In CP, navigation is differently impaired than visual spatial memory, and less tightly related to preterm birth, basic visual function, and deep white matter injury. The exploration of navigational space could prove useful in enhancing spatial representation and reference-frame manipulation in CP.