Neuropsychological evaluation of language.

Neuropsychological evaluation of language may be based on the psychometric approach or on extensive exploration of modular functions according to cognitive or linguistic theory. Various approaches have several features in common, although some emphasize individual functions, and others explore syndromes in brain-damaged populations. Systematic assessment of language has been developed according to the goals of various clinicians and researchers. Beyond the diagnostic need, prognosis, and planning for therapy, there are important theoretical reasons to have standardized aphasia tests and complementary experimental explorations of language deficit. Objective quantitation of deficit allows the study of the anatomical and physiological organization of language-related structures. It also contributes to the relationship of language and other modalities of cognition, hemispheric lateralization, language development in children, and language dissolution in degenerative disease. The requirements, content, standardization, and application of aphasia tests are discussed.