Objective Cerebral 18F-FDG PET complements bedside examination with behavioural scales in patients with DOC enabling better functional categorization. We realized a resting PET, then another after motor/visual activation, in patients with DOC according to their clinical course. Material/patients and methods It is a retrospective mono central study in our acute inpatients rehabilitation unit between 2011 and 2014. Our group consists of 14 patients (whom 5 women) with DOC, 18–70 years old at moment of brain injury (6 severe TBI, 4 anoxia, 3 hemorrhagic and 1 ischemic major strokes). All had months after brain lesions (average delay 186 days), DOC assessment by the Wessex head injury matrix (WHIM), a basal resting state PET, followed by an activated one consisting on providing motor or visual stimulation during second PET. Distant WHIM was performed at least 6 months after (average 14.8 months). We defined 3 groups: (1) WHIM at [1–14], (2) WHIM at [15–29] and (3) WHIM at [30–58]. We analysed, by compared T test of each patient, metabolic increment between basal and activated PET-scan according to clinical course. Results All patients had initial significant increase of metabolism in the activated PET-scan compared with basal ones, but patterns were not always consistent with assigned task. But this significant activation (FWE [P < 0,005]) was particularly located in left occipital, parietal and temporal associative areas, among patients with further best clinical course. Discussion - conclusion All sever DOC had metabolic increase on activated PET-scan during first year post injury (average 6 months). Among patients with best clinical course we noticed that initial increased metabolism was located in left visual associative cortex and language/phonology treatment areas.