Preservation of Brain Activity in Unresponsive Patients Identifies MCS Star

• Published in: Annals of neurology Vol. 90; no. 1; pp. 89 - 100
• Main Authors: Thibaut, Aurore, Panda, Rajanikant, Annen, Jitka, Sanz, Leandro R. D., Naccache, Lionel, Martial, Charlotte, Chatelle, Camille, Aubinet, Charlène, Bonin, Estelle A. C., Barra, Alice, Briand, Marie‐Michèle, Cecconi, Benedetta, Wannez, Sarah, Stender, Johan, Laureys, Steven, Gosseries, Olivia
• Format: Journal Article Web Resource
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2021; Wiley Subscription Services, Inc; Wiley; John Wiley & Sons
• Subjects: Atrophy; Brain; Brain Metabolism; Cognitive Motor Dissociation; Coma; Consciousness; Covert Cogntition; Diagnosis; Human health and pathology; Human health sciences; Hypometabolism; Life Sciences; Metabolism; Minimally Conscious State; Neural networks; Neurologie; Neurology; Patients; Positron emission; Positron emission tomography; Preservation; Sciences de la santé humaine; Sleep and wakefulness; Substantia grisea; Tomography; Unresponsive Wakefulness Syndrom; Vegetative State; Wakefulness
• ISSN: 0364-5134; 1531-8249; 1531-8249
• DOI: 10.1002/ana.26095

Objective Brain‐injured patients who are unresponsive at the bedside (ie, vegetative state/unresponsive wakefulness syndrome – VS/UWS) may present brain activity similar to patients in minimally conscious state (MCS). This peculiar condition has been termed “non‐behavioural MCS” or “MCS*”. In the present study we aimed to investigate the proportion and underlying brain characteristics of patients in MCS*. Methods Brain 18F‐fluorodeoxyglucose Positron Emission Tomography (FDG‐PET) was acquired on 135 brain‐injured patients diagnosed in prolonged VS/UWS (n = 48) or MCS (n = 87). From an existing database, relative metabolic preservation in the fronto‐parietal network (measured with standardized uptake value) was visually inspected by three experts. Patients with hypometabolism of the fronto‐parietal network were labelled “VS/UWS”, while its (partial) preservation either confirmed the behavioural diagnosis of “MCS” or, in absence of behavioural signs of consciousness, suggested a diagnosis of “MCS*”. Clinical outcome at 1‐year follow‐up, functional connectivity, grey matter atrophy, and regional brain metabolic patterns were investigated in the three groups (VS/UWS, MCS* and MCS). Results 67% of behavioural VS/UWS presented a partial preservation of brain metabolism (ie, MCS*). Compared to VS/UWS patients, MCS* patients demonstrated a better outcome, global functional connectivity and grey matter preservation more compatible with the diagnosis of MCS. MCS* patients presented lower brain metabolism mostly in the posterior brain regions compared to MCS patients. Interpretation MCS* is a frequent phenomenon that is associated with better outcome and better brain preservation than the diagnosis of VS/UWS. Complementary exams should be provided to all unresponsive patients before taking medical decisions. ANN NEUROL 2021;90:89–100