To study the functional connectivity in patients with severe acquired brain injury is very challenging for their high level of disability because of a prolonged period of coma, extended lesions, and several cognitive and behavioral disorders. In this article, we investigated in these patients the default mode network and somatomotor connectivity changes at rest longitudinally, in the subacute and late phase after brain injury. The aim of the study is to characterize such connectivity patterns and relate the observed changes to clinical and neuropsychological outcomes of these patients after a period of intensive neurorehabilitation. Our findings show within the default mode network a disruption of connectivity of medial pre-frontal regions and a significant change of amplitude of internal connections. Notably, strongest changes in functional connectivity significantly correlated to consistent clinical and cognitive recovery. This evidence seems to indicate that the reorganization of the Default Mode Network may represent a valid biomarker for the cognitive recovery in patients with severe acquired brain injury.
Keywords: cognitive recovery; functional connectivity; magnetic resonance imaging; neurorehabilitation; severe acquired brain injury.