Visual-perceptual impairment in a random sample of children with cerebral palsy.

Several studies have tried to establish the prevalence of visual-perceptual impairment in children with physical disabilities, particularly in those with cerebral palsy (CP), but failed to take into account the selective impairment of non-verbal intelligence that is frequent in these children. This has resulted in the confounding of visual-perceptual and non-verbal intelligence impairment. In the present study we aimed to determine how widespread visual-perceptual impairment is in children with CP by evaluating perceptual ability together with the performance level on non-verbal intelligence subtests. All children (n=96; 44 females, 52 males) who attended an institute for children with physical disabilities were included (age ranged from 4 years 11 months to 21 years 5 months) who had a non-verbal mental age between 3 and 7 years; Total IQ was <85 in 91% of participants. They were given a grating acuity task and the visual-perceptual battery L94, comprising six visual object recognition and two visuoconstruction tasks. Relative to their performance level on non-verbal intelligence subtests, 37.5% of the children were impaired on at least one task, and 18.7% on two or more tasks. No child was impaired on the visuoconstruction tasks. Visual-perceptual impairment was highest among six children with brain malformation (67%), followed by spastic CP (40%), and brain damage acquired after the first year of life (38%). There was no difference in visual-perceptual impairment between the subtypes of spastic CP. Results are not secondary to visual acuity deficits, as only one L94 task was significantly correlated with acuity impairment. We conclude that visual-perceptual impairment is frequent in children with physical disabilities, and not restricted to children with CP of hypoxic-ischaemic origin.