Neuropsychological assessment of receptive language comprehension with event-related brain potentials

While there is a long and distinguished history of evaluating sensory functions with evoked potentials, few researchers have successfully demonstrated the utility of event-related brain potentials (ERPs) in the assessment of cognitive functions. Recently, researchers have adapted standardized neuropsychological measures of receptive vocabulary for computer presentation with simultaneous ERP recordings (e.g., Byrne et al., 1995). These investigations provided the initial demonstration that ERP components (e.g., the P300) can be elicited by standardized test stimuli and thus utilized to evaluate language functions, independent of a behavioural response. Disturbances in language comprehension are frequently noted in aphasic individuals following a stroke, but are not always readily assessable with traditional psychometric measures due to limitations of motoric and communicative responses. Accordingly, the objective of the current investigation was to adapt neuropsychological measures of language comprehension to ERP methodology and explore whether the correct and incorrect test items could be differentiated on the basis of a neural response. Experiment One examined reading comprehension with the Written Comprehension section of the Psycholinguistic Assessments of Language Processing in Aphasia (Kay et al., 1992). Experiment Two examined speech comprehension with the Token Test (Boller and Vignolo, 1966; De Renzi and Vignolo, 1962). The findings in both experiments revealed the expected neural differentiation at both the group and individual levels. This investigation represented the normative data collection phase in an ongoing endeavor to assess language functions in neurological patients who cannot be evaluated by traditional methods.