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.