Visual Recognition and Visually Guided Action After Early Bilateral Lesion of Occipital Cortex: A Behavioral Study of a 4.6-year-old Girl

Abstract

We report the case of a 4.6-year-old girl born pre-term with early bilateral occipital damage. It was revealed that the child had non-severely impaired basic visual abilities and ocular motility, a selective perceptual deficit of figure-ground segregation, impaired visual recognition and abnormal navigating through space. Even if the child's visual functioning was not optimal, this was the expression of adaptive anatomic and functional brain modifications that occurred following the early lesion. Anatomic brain structure was studied with anatomic MRI and Diffusor Tensor Imaging (DTI)-MRI.

This behavioral study may provide an important contribution to understanding the impact of an early lesion of the visual system on the development of visual functions and on the immature brain's potential for reorganisation related to when the damage occurred.

We gratefully remember Professor Marcello Mario Pierro for leading the research and clinical work in Pediatric Neurorehabilitation with enormous passion and absolute dedication. We thank Dr. Marco Montes, of Ophthalmology Unity, for assistance with V.E.P. study.

We thank Rosa Maria Conte for her precious collaboration in the translation. This study was supported by grants from Italian Ministry of Health-Project: ICS 120.2/RF2003.PS/03/3.

Notes

¹ Payne et al. (1996) divided visual capacities after lesions of the primary visual cortex into three main categories: First, residual vision describes visual capacities that depend on pathways remaining after lesions in adulthood. Second, recovered vision describes the visual capacities that remain after lesions if they emerge from, and are superior to, residual vision. It implies the prior presence of a given behavior. Recovery is rarely complete. Third, spared vision describes the visual capacities that are present after lesions occurring early in life. It implies the prior absence of a behavior and the development of altered SNC connections. It is always greater than both residual and recovered vision, but the level of sparing depends on the age at which the lesion occurred and on the extent of the lesion.