Visual implicit memory deficit and developmental surface dyslexia: a case of early occipital damage.

This study reports the case of EBON, a fifteen-year-old right-handed female Swedish student, who suffered an early medial/dorsal occipital brain lesion and showed a clearly defined pattern of developmental surface dyslexia. EBON and 17 controls were examined with within and cross-modality (visual and auditory) word stem completion tasks together with tasks requiring free-recall and recognition for visually and auditory presented words. Compared to age-matched controls, EBON was found to show a significant deficit of visual priming following visual presentation, and a deficit approaching significance following auditory presentation. Explicit memory and visual and spatial abilities were not significantly different from controls. Therefore, EBON represents the first childhood case establishing the role of occipital regions in visual priming, as well as illustrating a profile of surface reading difficulty as a developmental consequence of this locus of lesion.