The effects of cortical ischemic stroke on auditory processing in humans as indexed by transient brain responses

ObjectiveTo investigate the effects of cortical ischemic stroke and aphasic symptoms on auditory processing abilities in humans as indicated by the transient brain response, a recently documented cortical deflection which has been shown to accurately predict behavioral sound detection.MethodsUsing speech and sinusoidal stimuli in the active (attend) and the passive (ignore) recording condition, cortical activity of ten aphasic stroke patients and ten control subjects was recorded with whole-head MEG and behavioral measurements.ResultsStroke patients exhibited significantly diminished neuromagnetic transient responses for both sinusoidal and speech stimulation when compared to the control subjects. The attention-related increase of response amplitude was slightly more pronounced in the control subjects than in the stroke patients but this difference did not reach statistical significance.ConclusionsLeft-hemispheric ischemic stroke impairs the processing of sinusoidal and speech sounds. This deficit seems to depend on the severity and location of stroke.SignificanceDirectly observable, non-invasive brain measures can be used in assessing the effects of stroke which are related to the behavioral symptoms patients manifest.