Event-related potentials indicate bi-hemispherical changes in speech sound processing during aphasia rehabilitation.
OBJECTIVE
To investigate changes in brain activation related to tone and speech sound processing during aphasia rehabilitation.


METHODS
Longitudinal study investigating patients with stroke, subarachnoid hemorrhage and traumatic brain injury 3 and 7 months post-injury.


METHODS
Eight patients with aphasia, reflecting a wide range of auditory comprehension impairment.


METHODS
Token test and Norwegian Basic Aphasia Assessment were used to measure auditory comprehension function. Brain event-related potentials were recorded in passive paradigms with harmonically rich tones and syllables in order to obtain the mismatch negativity component that reflects automatic stimulus discrimination. In an active syllable discrimination paradigm, stimulus feature integration (N1), attended stimulus discrimination and classification (N2), and target detection (P3) were studied.


RESULTS
Auditory comprehension scores improved approximately 10% during the observation period. Ipsilesional frontal P3- and N2-amplitude increased significantly. A significant shift in topographical distribution from the contralesional to the ipsilesional hemisphere was observed for the N2 component. The study of individual waveforms indicates inter-individual differences in reorganization after brain injury.


CONCLUSIONS
Hemispherical distribution of brain activation correlating with speech sound processing in aphasia can change during the first months after brain injury. Event-related potentials are a potentially useful method for detecting individual activation patterns relevant to recovery in aphasia rehabilitation.
Becker
Frank
F
Sunnaas Rehabilitation Hospital, Faculty Division Ullevål University Hospital, University of Oslo, Oslo, and Department of Research, Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway. frank.becker@sunnaas.no
Reinvang
Ivar
I
D000293:Adolescent; D000328:Adult; D000368:Aged; D001037:Aphasia / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation*; D001931:Brain Mapping; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D013060:Speech / Q000502:physiology; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology; D020521:Stroke / Q000150:complications / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000503:physiopathology / Q000534:rehabilitation