Cortical information processing in coma.
OBJECTIVE
To evaluate cortical information processing (particularly, semantic processing) in acute nontraumatic coma by means of event-related brain potentials (ERPs).


METHODS
The tests included measures of obligatory auditory processing (N100), automatic (Mismatch Negativity) and controlled (P300) detection of stimulus deviance, and semantic processing (ERP effects in word pairs and sentences). The tests were presented to 20 healthy participants and 42 coma patients with Glasgow Coma Scale <9.


RESULTS
Responders (ie, patients whose ERP data indicate that their brain was able to process the corresponding stimuli) were found in each ERP test, and their distribution was statistically different from that expected by chance. Particularly, 7 responders were found in the word pair paradigm and 3 responders in the sentence paradigm. The P300 responsiveness highly correlated with other ERP responses, with Glasgow Coma Scale and with the future development of coma (ie, P300 on day 4 was related to the clinical state on day 20).


CONCLUSIONS
Results suggest a wide range of cortical information processing in coma, including semantic processing. The question is discussed of whether, and to what extent, these processing operations are related to conscious awareness of stimuli.
Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
Jerôme
J
Daltrozzo
Norma
N
Wioland
Veronique
V
Mutschler
Philippe
P
Lutun
Bartholomeus
B
Calon
Alain
A
Meyer
Thierry
T
Pottecher
Simone
S
Lang
Albert
A
Jaeger
Boris
B
Kotchoubey
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001307:Auditory Perception / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D003128:Coma / Q000503:physiopathology* / Q000523:psychology*; D003243:Consciousness; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D014057:Tomography, X-Ray Computed