EPOS

European Paediatric Ophthalmological Society

Abstract Preview

47 Impaired movement through 3D space and impaired simultaneous perception in children with cerebral visual impairment. A retrospective observational study

Saaed, A., Dutton, G.N.
Royal Hospital for Sick Children, Glasgow, Scotland

Purpose: Visual information is processed in the brain by two discrete but linked subsystems. The dorsal stream passes information to the posterior parietal lobes to process complex images, to the motor cortex to allow movement through 3D space and to the frontal cortex to coordinate saccadic eye movements. The ventral stream conveys data to the temporal lobes and subserves visual recognition, orientation and visual memory. This paper reviews the clinical features in a cohort of children who have difficulty moving through 3D space associated with impaired simultaneous perception as a complication of presumed dorsal stream pathology.

Methods: The records of 364 children with damage to the brain attending a visual assessment clinic were reviewed. The children with impaired movement through 3D space were identified, and the clinical and visual features documented.

Results: Forty children were described as having impaired movement through 3D space, of whom 34 also manifested impaired simultaneous perception. 27 children had visual field deficits (23 had lower visual field impairment and 4 showed hemianopic deficits). 14 of these children had inaccurate reach. All had difficulty coordinating the movement of their legs to navigate steps and kerbs, and 28 were also unable to identify whether a change in a floor surface (eg carpet/linoleum) was a step or not. Stereo-acuity had been measured in 10 cases and was normal in 7.

Conclusion: We hypothesise that damage to the dorsal stream disrupts the command for movement of the limbs through visual space, and that the pathways subserving lower limb movement may be selectively damaged. Impaired perception of complex visual scenes is a common association.