Background: Prader-Willi syndrome (PWS) is characterised by hypotonia, hypogonadism, short stature, obesity, behavioural problems, intellectual disability, and delay in language, social and motor development. There is very limited knowledge about visual-motor integration in children with PWS. Method: Seventy-three children with PWS aged 7-17 years were included. Visual-motor integration was assessed using the Beery Visual-motor Integration test at the start of the study and after 2 years. The association between visual-motor integration and age, gender, genetic subtype and intelligence was assessed. Results: Children with PWS scored 'very low' (-3 standard deviations) in visual-motor integration and 'below average' (-1 standard deviation) in visual perception and motor coordination compared with typically developing children. Visual-motor integration was higher in children with a deletion (β=-0.170, P=0.037), in older children (β=0.222, P=0.009) and in those with a higher total IQ (β=0.784, P<0.001). Visual perception was higher with a deletion (β=-0.193, P=0.044) and higher IQ (β=-0.618, P<0.001), but motor coordination was only higher with a higher total IQ (β=0.429, P=0.001). Visual perception and motor coordination were not associated with age or gender. There was a trend for visual-motor integration decline over the 2 year follow-up period (P=0.099). Visual perception and motor coordination did not change over the follow-up period. Conclusions: Visual-motor integration is very poor in children with PWS. Children scored higher on the time-limited subtests for visual perception and motor coordination than the combined test for visual-motor integration. Separation of visual-motor integration tasks into pure visual or motor tasks and allowing sufficient time to perform the tasks might improve daily activities, both at home and at school.

Motor coordination, Prader-Willi syndrome, Visual perception, Visual-motor integration,
Journal of Intellectual Disability Research
Department of Pediatrics

Lo, S.T, Collin, P.J.L, & Hokken-Koelega, A.C.S. (2015). Visual-motor integration in children with Prader-Willi syndrome. Journal of Intellectual Disability Research, 59(9), 827–834. doi:10.1111/jir.12197