title: The neural correlates of lexical processing in disorders of consciousness.
abstract: There is a growing interest in the use of functional imaging to assess brain activity in the absence of behavioural responses in patients with disorders of consciousness (DOC). In the present study, we applied a hierarchical auditory stimulation paradigm to functional magnetic resonance (fMRI) in a group of long-term DOC adult patients. Brain response to pairs of pseudowords, of unrelated words and of semantically related words, i.e. stimuli differing in lexical status (words vs. pseudowords) and semantic relatedness (related vs. unrelated) was assessed. The former contrast was considered to reflect the automatic brain response to the passive presentation of meaningful real words, while the latter aimed to assess the response to meaning relationships. The results of the study indicate that automatic lexical processing can be observed in minimally conscious state (MCS), but also in vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients, as indicated by increase in blood oxygenation level dependent (BOLD) activity in the linguistic networks. DOC patients, for some task conditions, recruited additional areas in comparison to healthy participants. Furthermore this study provides additional evidence of the potential role of fMRI in the assessment of residual cognitive processing in some of these patients, which may not be evident at the clinical level.
authors.affiliation: Neuroradiology Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Via Celoria 11, 20133, Milan, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Nigri
authors.affiliation: School of Advanced Studies IUSS, Pavia, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Catricalà
authors.affiliation: Neuroradiology Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Via Celoria 11, 20133, Milan, Italy. stefania.ferraro@istituto-besta.it.
authors.forename: Stefania
authors.initials: S
authors.lastname: Ferraro
authors.affiliation: Neuroradiology Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Via Celoria 11, 20133, Milan, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bruzzone
authors.affiliation: Neuroradiology Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Via Celoria 11, 20133, Milan, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: D'Incerti
authors.affiliation: Neurology, Public Health and Disability Unit, Scientific Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Milan, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Sattin
authors.affiliation: Neurophysiopathology and Epilepsy Centre, Neurological Institute "Carlo Besta", IRCCS Foundation, Milan, Italy.
authors.forename: Davide Rossi
authors.initials: DR
authors.lastname: Sebastiano
authors.affiliation: Neurophysiopathology and Epilepsy Centre, Neurological Institute "Carlo Besta", IRCCS Foundation, Milan, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Franceschetti
authors.affiliation: Department of Nuclear Medicine, Ca' Granda Ospedale Maggiore Policlinico, IRCCS Foundation, Milan, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Marotta
authors.affiliation: Department of Nuclear Medicine, Ca' Granda Ospedale Maggiore Policlinico, IRCCS Foundation, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Benti
authors.affiliation: Neurology, Public Health and Disability Unit, Scientific Department, Neurological Institute "Carlo Besta", IRCCS Foundation, Milan, Italy.
authors.forename: Matilde
authors.initials: M
authors.lastname: Leonardi
authors.affiliation: School of Advanced Studies IUSS, Pavia, Italy.|Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Stefano F
authors.initials: SF
authors.lastname: Cappa
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003244:Consciousness Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008037:Linguistics; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D049268:Positron-Emission Tomography; D012720:Severity of Illness Index; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Disorder of consciousness; Lexical processing; Minimally conscious state; Priming; Vegetative state; fMRI