title: EEG-detected olfactory imagery to reveal covert consciousness in minimally conscious state.
abstract: OBJECTIVE
  To reveal covert abilities in a minimally conscious state (MCS) through an innovative activation paradigm based on olfactory imagery.
  
  
  METHODS
  Case study.
  
  
  METHODS
  A patient in MCS was asked to 'imagine an unpleasant odour' or to 'relax' in response to the appearance on a screen of a downward pointing arrow or a cross, respectively. Electrophysiological responses to stimuli were investigated by means of an 8-channel EEG equipment and analysed using a specific threshold algorithm. The protocol was repeated for 10 sessions separated from each other by 2 weeks. Accuracy, defined as the number of successes with respect to the total number of trials, was used to evaluate the number of times in which the classification strategy was successful.
  
  
  RESULTS
  Analyses of accuracy showed that the patient was able to activate and to relax himself purposefully and that he optimized his performances with the number of sessions, probably as a result of training-related improvements.
  
  
  CONCLUSIONS
  Subtle signs of consciousness may be under-estimated and need to be revealed through specific activation tasks. This paradigm may be useful to detect covert signs of consciousness, especially when patients are precluded from carrying out more complex cognitive tasks.
authors.affiliation: a Neurological Institute, Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila , L'Aquila , Italy .
authors.forename: Francesca
authors.initials: F
authors.lastname: Pistoia
authors.affiliation: a Neurological Institute, Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila , L'Aquila , Italy .
authors.forename: Antonio
authors.initials: A
authors.lastname: Carolei
authors.affiliation: b Department of Computer , Control and Management Engineering, Sapienza University of Rome , Rome , Italy .
authors.forename: Daniela
authors.initials: D
authors.lastname: Iacoviello
authors.affiliation: c Department of Health , Life and Environmental Sciences, University of L'Aquila , L'Aquila , Italy , and.
authors.forename: Andrea
authors.initials: A
authors.lastname: Petracca
authors.affiliation: a Neurological Institute, Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila , L'Aquila , Italy .
authors.forename: Simona
authors.initials: S
authors.lastname: Sacco
authors.affiliation: d Post-Coma and Rehabilitation Care Unit, San Raffaele Hospital , Cassino , Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Sarà
authors.affiliation: c Department of Health , Life and Environmental Sciences, University of L'Aquila , L'Aquila , Italy , and.
authors.forename: Matteo
authors.initials: M
authors.lastname: Spezialetti
authors.affiliation: c Department of Health , Life and Environmental Sciences, University of L'Aquila , L'Aquila , Italy , and.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Placidi
mesh_terms: D000328:Adult; D001921:Brain; D003128:Coma / Q000473:pathology / Q000503:physiopathology; D003243:Consciousness / Q000145:classification / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D006801:Humans; D008297:Male; D055696:Olfactory Perception / Q000502:physiology*; D018458:Persistent Vegetative State / Q000175:diagnosis / Q000503:physiopathology*; D011379:Prognosis
keywords: EEG; imagery; minimally conscious state; unresponsive wakefulness syndrome; vegetative state, task