Van der Meer ALH, van der Weel FR. Development of perception in action in healthy and at-risk children. Acta Paediatr 1999; Suppl 429: 29-36. Stockholm. ISSN 0803-5326 Devising effective assessment techniques and therapy for movement disorders in young children requires in-depth measures of the child's perceptuo-motor functioning. It is argued that the field of movement disorders can benefit from an ecological approach to perception and action, where perception subserves action and action influences perception. Three notions central to the ecological approach are described and illustrated with our recent research on infant and child perceptual and motor behaviour. & Cerebral palsy, ecological approach to perception and action, measuring movement disorders, neurological assessment, premature birth ALH van der Meer,