Electrophysiological assessment of language function following stroke.
OBJECTIVE
Event-related brain potentials (ERPs) were used to assess language function after stroke and demonstrate that it is possible to adapt neuropsychological tests to evaluate neurocognitive function using ERPs. Prior ERP assessment work has focused on language in both healthy individuals and case studies of aphasic neurotrauma patients. The objective of the current study was to evaluate left-hemisphere stroke patients who had varying degrees of receptive language impairment. It was hypothesized that ERPs would assess receptive language function accurately and correlate highly with the neuropsychological data.


METHODS
Data were collected from 10 left-hemisphere stroke patients; all were undergoing rehabilitation at the time of testing. Each patient received a battery of neuropsychological tests including the Peabody Picture Vocabulary Test-Revised (PPVT-R; Minnesota: American Guidance Service, 1981). ERPs were recorded during a computerized PPVT-R, in which pictures are presented followed by digitized spoken words that are either congruent or incongruent with the pictures.


CONCLUSIONS
Incongruent spoken words within an individual's vocabulary level elicited well-known ERP components. One of the components (the N400) could be utilized as a marker of intact semantic processing. The ERP results were subsequently quantified and N400 derivative scores correlated highly with the neuropsychological findings. The results provided a clear demonstration of the efficacy of ERP-based assessment in a neurological patient group.


CONCLUSIONS
Language function in stroke patients can be evaluated, independent of behavior, using electrophysiological measures that correlate highly with traditional neuropsychological test scores.
D'Arcy
Ryan C N
RC
Cognitive/Clinical Neuroscience Unit, Department of Psychology, Dalhousie University, MB R3B 1Y6, Halifax, Canada. ryan.d'arcy@nrc.ca <ryan.d'arcy@nrc.ca>
Marchand
Yannick
Y
Eskes
Gail A
GA
Harrison
Edmund R
ER
Phillips
Stephen J
SJ
Major
Alma
A
Connolly
John F
JF
D000161:Acoustic Stimulation; D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D020521:Stroke / Q000175:diagnosis* / Q000503:physiopathology*