MRI brain lesion patterns in patients in anoxia-induced vegetative state

The object of this study was to analyze magnetic resonance imaging data from patients with disorders of consciousness who were suffering from non-traumatically induced brain lesions with respect to the pattern of vulnerability and to examine the associations between the sizes of these lesions and the clinical outcome of the patients. To this end, T1- and T2-weighted brain images were examined in twelve patients in the post-anoxic vegetative state after a median of 21 days after the causative event. Predominant in the characteristic lesion patterns were regions of pathological white matter signals within the frontal and occipital lobes and in the periventricular regions. The total volumes of the lesions were found to be associated with the severity of the patients' clinical outcomes as measured by the Ranchos Los Amigos Cognitive Scale after a median of 25 months. These lesion patterns demonstrated damage to cerebral networks critical to higher cognitive processes ("consciousness") in both white and gray matter. The relevance of these findings for patients in anoxia-induced decreased levels of consciousness is discussed.