Visual-motor integration in children with Prader-Willi syndrome

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.

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.

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.

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.