Alternative cerebral generators and circuitry pathways in alpha coma revealed by independent component analysis

ObjectiveThis study investigates the generators of alpha coma activity and the probable cerebral pathways involved in alpha coma patients.MethodsThis study uses independent component analysis (ICA) and dipole fitting algorithm to locate the cerebral generators in alpha coma and normal alpha rhythms.ResultsDistinct distributions of the source generators for alpha activity were noted in alpha coma. They were localized to the anterior neocortical and subcortical regions, which includes caudate nucleus, midbrain and hypothalamus. In addition, the two patients who survive long term have five independent components identified vs. the other five patients who demised only had one or two independent components.ConclusionsThe findings showed that alpha activity could be generated using alternative generators and pathways. This is probably due to the disinhibition of the normally inhibited pathways in coma. The presence of less independent components is probably a marker of less preserved brain tissue and predicts worse outcome.SignificanceThis is the first known human study using the ICA method to localize the cerebral generators in alpha coma. It might provide a new dimension of interpreting clinical EEGs in patients with alpha coma. It also might have significant application in predicting the clinical outcomes.