Modality-specific naming impairment after traumatic brain injury (TBI).

OBJECTIVE: To investigate neurocognitive and language functions in a single case presenting with modality-specific naming difficulties secondary to traumatic brain injury (TBI). DESIGN: A comprehensive neuropsychological testing and specific assessment of naming and recognition functions were administered. Follow-up testing was administered 2 years post-injury to evaluate syndrome evolution. Rehabilitative intervention is described. RESULTS: Ability to name visually presented objects was greatly impaired. The patient can describe or demonstrate the use of objects she cannot name and to sort them into their appropriate categories, indicating adequate non-verbal recognition. The impairment is specific to visual naming, as recognition through modalities different from vision is adequate (e.g. by touching the object, hearing its sound or being provided with verbal definition of it). This study and follow-up testing illustrated the evolution of the deficit, from a visual agnosic impairment to the co-occurrence of partial deficit of visual naming of objects and letters (optic aphasia and alexia). CONCLUSION: The patient presents with mild pre-semantic deficit (in mapping visual information with semantics) as well as post-semantic impairments (in the association between semantics and lexical label). Such performance can be accommodated within Farah's formulation which implies superadditive mild damage at several stages of object recognition naming model.

Visual recognition and visually guided action after early bilateral lesion of occipital cortex: a behavioral study of a 4.6-year-old girl.

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.