Impairment in understanding grasping movements in egocentric and allocentric perspectives in children with cerebral palsy due to periventricular leukomalacia

Recognizing and understanding the actions of others through motion information are vital functions for social adaptation. Conditions like neurological disorders and motor impairments can impact sensitivity to biological motion, highlighting the intricate relationship between perceiving and executing movements. Our study centred on assessing the ability of children, encompassing both those with typical development and those diagnosed with cerebral palsy due to periventricular leukomalacia (PVL), to discriminate between depicted grasping of a small cylinder and a large cube. This discrimination task involved observing a point-light animation depicting an actor grasping the object, presented from either an allocentric perspective (observing others) or an egocentric viewpoint (observing oneself). Notably, children with PVL exhibited a pronounced and specific impairment in this task, irrespective of the viewpoint, as evidenced by thresholds increasing by nearly a factor of two. When comparing this impairment to difficulties in form or motion perception, we identified a robust correlation between egocentric biological motion and form sensitivity. However, there was no similar correlation between motion and biological motion sensitivity, suggesting a deficit in the visual system rather than the visuo-motor control system. These findings contribute to our understanding of the intricate interplay between motor and visual processing in individuals with congenital brain lesions, shedding light on the significant involvement of the visual system in cases of PVL.