title: Substitute or complement? Defining the relative place of EEG and fMRI in the detection of voluntary brain reactions.
abstract: To improve the assessment of awareness in patients with disorders of consciousness, recent protocols using functional Magnetic Resonance Imaging (fMRI) have been developed, and led some specialized coma centers to use this method on a routine basis. Recently, promising results have also been observed with electroencephalography (EEG), a less expensive and widely available technique. However, since the spatiotemporal nature of the recorded signal differs between both EEG and fMRI, the question of whether one method could substitute or should complement the other method is a matter of debate. In this study, we compared the neural processes of two well-known EEG and fMRI mental imagery protocols to define the relative place of each method in the assessment of awareness. A group of 20 healthy volunteers performed both EEG and fMRI command-following and communication tasks. Distinct command following was found with both EEG and fMRI for five subjects, only with fMRI for 12 subjects, and only with EEG for one subject. In the communication task, neither EEG nor fMRI alone gave satisfactory results and no reliable communication could be established in approximately 1/3rd of the participants. If fMRI showed the best performance to detect volitional reactions in mental imagery tasks, our results provide evidence that the use of EEG must not be underestimated since a better detection was found with this method for at least one subject. More than being used as a substitute, EEG should complement fMRI to improve the detection of sign of awareness, and to reduce the risks of misjudgments.
authors: Laboratoire de Neurosciences de Besançon, Université de Franche-Comté, France; Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France. Electronic address: dgabriel@chu-besancon.fr.
authors: D
authors: D
authors: Gabriel
authors: Laboratoire de Mathématiques de Besançon, Université de Franche-Comté, France.
authors: J
authors: J
authors: Henriques
authors: Laboratoire de Neurosciences de Besançon, Université de Franche-Comté, France; Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France; Service de neurologie, CHRU Besançon, France.
authors: A
authors: A
authors: Comte
authors: Laboratoire de Mathématiques de Besançon, Université de Franche-Comté, France.
authors: L
authors: L
authors: Grigoryeva
authors: Laboratoire de Mathématiques de Besançon, Université de Franche-Comté, France; Centre National de la Recherche Scientifique, France.
authors: J-P
authors: JP
authors: Ortega
authors: Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France; Espace éthique Bourgogne Franche-Comte, France.
authors: E
authors: E
authors: Cretin
authors: Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France.
authors: G
authors: G
authors: Brunotte
authors: Laboratoire de Neurosciences de Besançon, Université de Franche-Comté, France; Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France; Service de psychiatrie de l'adulte, CHRU de Besançon, France.
authors: E
authors: E
authors: Haffen
authors: Laboratoire de Neurosciences de Besançon, Université de Franche-Comté, France; Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France; Service de neurologie, CHRU Besançon, France.
authors: T
authors: T
authors: Moulin
authors: Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France; Département douleur soins palliatifs, CHRU de Besançon, France.
authors: R
authors: R
authors: Aubry
authors: Centre d'investigation Clinique-Innovation Technologique, Inserm 808, CHRU de Besançon, France.
authors: L
authors: L
authors: Pazart
mesh_terms: D000328:Adult; D000368:Aged; D001364:Awareness / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003142:Communication; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011795:Surveys and Questionnaires; D014836:Volition / Q000502:physiology*
keywords: EEG; consciousness; functional MRI; mental imagery; neuroimaging