Identifying the default-mode component in spatial IC analyses of patients with disorders of consciousness

• Published in: Human brain mapping Vol. 33; no. 4; pp. 778 - 796
• Main Authors: Soddu, Andrea, Vanhaudenhuyse, Audrey, Bahri, Mohamed Ali, Bruno, Marie-Aurelie, Boly, Mélanie, Demertzi, Athena, Tshibanda, Jean-Flory, Phillips, Christophe, Stanziano, Mario, Ovadia-Caro, Smadar, Nir, Yuval, Maquet, Pierre, Papa, Michele, Malach, Rafael, Laureys, Steven, Noirhomme, Quentin
• Format: Journal Article Web Resource
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.04.2012; Wiley-Liss; John Wiley & Sons, Inc; Wiley Liss, Inc
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Brain - physiopathology; Brain Mapping - methods; Child; consciousness; Consciousness Disorders - physiopathology; default mode; Female; fMRI; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Image Interpretation, Computer-Assisted - methods; independent component analysis; Infant; Investigative techniques, diagnostic techniques (general aspects); locked-in syndrome; Magnetic Resonance Imaging - methods; Male; Medical sciences; Middle Aged; Nerve Net - physiopathology; Nervous system; Nervous system (semeiology, syndromes); Neurology; Physical, chemical, mathematical & earth Sciences; Physics; Physique; Physique, chimie, mathématiques & sciences de la terre; Radiodiagnosis. Nmr imagery. Nmr spectrometry; resting state; vegetative state; Young Adult; Coma; Human; default mode; Nervous system diseases; Radiodiagnosis; consciousness; Locked-in syndrome; Consciousness impairment; Spatial analysis; Vegetative state; Nuclear magnetic resonance imaging; fMRI; independent component analysis; resting state; Neurological disorder
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.21249

Objectives:Recent fMRI studies have shown that it is possible to reliably identify the default‐mode network (DMN) in the absence of any task, by resting‐state connectivity analyses in healthy volunteers. We here aimed to identify the DMN in the challenging patient population of disorders of consciousness encountered following coma. Experimental design: A spatial independent component analysis‐based methodology permitted DMN assessment, decomposing connectivity in all its different sources either neuronal or artifactual. Three different selection criteria were introduced assessing anticorrelation‐corrected connectivity with or without an automatic masking procedure and calculating connectivity scores encompassing both spatial and temporal properties. These three methods were validated on 10 healthy controls and applied to an independent group of 8 healthy controls and 11 severely brain‐damaged patients [locked‐in syndrome (n = 2), minimally conscious (n = 1), and vegetative state (n = 8)]. Principal observations: All vegetative patients showed fewer connections in the default‐mode areas, when compared with controls, contrary to locked‐in patients who showed near‐normal connectivity. In the minimally conscious‐state patient, only the two selection criteria considering both spatial and temporal properties were able to identify an intact right lateralized BOLD connectivity pattern, and metabolic PET data suggested its neuronal origin. Conclusions: When assessing resting‐state connectivity in patients with disorders of consciousness, it is important to use a methodology excluding non‐neuronal contributions caused by head motion, respiration, and heart rate artifacts encountered in all studied patients. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.