Consciousness in Coma?

Are coma patients still able of cognition and emotion
and to what extend? Such questions can be
investigated with auditory Event-Related Potentials
(ERPs) and Skin Conductance Response (SCR). Cognitive
functions were tested with several paradigms in 44
coma patients and emotional response in fifteen of
them. In at least 7 % (N=44) of these patients an
explicit semantic processing and thus a minimal
remaining consciousness could not be excluded. This
study is the first to demonstrate semantic processing
in coma. We found a correlation between emotional SCR
and level of consciousness as measured by the GCS and
the Cook and Palma scores in agreement with the weak
emotional SCR observed in these patients. Some ERPs,
when observed in coma have also a prognosis value. We
conducted a meta-analysis on 337 to 612 patients
showing that the N100, the Mismatch Negativity, and
the P300 predict awakening from coma. This work
provides new insights on the coma state and suggests
new methods of assessment of these patients for
medical practitioners.

Autorentext

Jérôme Daltrozzo, Ph.D.: Physiology at Louis Pasteur Universityof Strasbourg (France). Postdoc at INSERM U821, Lyon 1 University(France)

Klappentext

Are coma patients still able of cognition and emotionand to what extend? Such questions can beinvestigated with auditory Event-Related Potentials(ERPs) and Skin Conductance Response (SCR). Cognitivefunctions were tested with several paradigms in 44coma patients and emotional response in fifteen ofthem. In at least 7 % (N=44) of these patients anexplicit semantic processing and thus a minimalremaining consciousness could not be excluded. Thisstudy is the first to demonstrate semantic processingin coma. We found a correlation between emotional SCRand level of consciousness as measured by the GCS andthe Cook and Palma scores in agreement with the weakemotional SCR observed in these patients. Some ERPs,when observed in coma have also a prognosis value. Weconducted a meta-analysis on 337 to 612 patientsshowing that the N100, the Mismatch Negativity, andthe P300 predict awakening from coma. This workprovides new insights on the coma state and suggestsnew methods of assessment of these patients formedical practitioners.