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Riganello F.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | Garbarino S.,University of Genoa | Sannita W.G.,University of Genoa | Sannita W.G.,State University of New York at Stony Brook
Journal of Psychophysiology | Year: 2012

Measures of heart rate variability (HRV) are major indices of the sympathovagal balance in cardiovascular research. These measures are thought to reflect complex patterns of brain activation as well and HRV is now emerging as a descriptor thought to provide information on the nervous system organization of homeostatic responses in accordance with the situational requirements. Current models of integration equate HRV to the affective states as parallel outputs of the central autonomic network, with HRV reflecting its organization of affective, physiological, "cognitive," and behavioral elements into a homeostatic response. Clinical application is in the study of patients with psychiatric disorders, traumatic brain injury, impaired emotion-specific processing, personality, and communication disorders. HRV responses to highly emotional sensory inputs have been identified in subjects in vegetative state and in healthy or brain injured subjects processing complex sensory stimuli. In this respect, HRV measurements can provide additional information on the brain functional setup in the severely brain damaged and would provide researchers with a suitable approach in the absence of conscious behavior or whenever complex experimental conditions and data collection are impracticable, as it is the case, for example, in intensive care units. © 2012 Federation of European Psychophysiology Societies. Source

Candelieri A.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | Candelieri A.,University of Calabria | Riganello F.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | Cortese D.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | And 2 more authors.
HEALTHINF 2011 - Proceedings of the International Conference on Health Informatics | Year: 2011

Eye-tracking is defined as the "pursuit eye movement or sustained fixation that occurs in direct response to moving or salient stimuli"; it is a key descriptor of the evolution from the vegetative (VS) to the minimally conscious (MCS) state and predicts better outcome. In this study, several physiological parameters (such as heart beat, Galvanic Skin Response [GSR], Blood Volume Pulse [BVP], respiratory rate and amplitude) were recorded while a medical examiner searched for eye-tracking by slowly moving a visual stimulus horizontally and vertically in front of the subject. Seven patients in VS and 8 in MCS were studied. The Heart Rate Variability (HRV) was analyzed to obtain time and frequency descriptors. Different classification methods were adopted to search for a plausible relationship between the subject psychophysiological state and observable eye-tracking to stimuli. The performance of different classifiers was computed as Balanced Classification Accuracy (BCA) and evaluated through suitable validation technique. A Support Vector Machine (SVM) classifier provided the most reliable relationship: BCA mean was about 84% on fold cross validation and about 75% on an independent test set of 6 patients (3 VS and 3 MCS). Source

Dolce G.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | Lucca L.F.,S Anna Institute | Candelieri A.,S Anna Institute And Ran Research In Advanced Neurorehabilitation | Candelieri A.,University of Calabria | And 4 more authors.
Journal of Neurotrauma | Year: 2011

Visual pursuit is a key descriptor of the minimally conscious state (above 80% of cases). It is also observable in about 20% of subjects in vegetative state. Its reappearance after severe brain damage anticipates a favorable outcome, with recovery of consciousness in 73% of subjects (45% in the absence of it). We considered retrospectively 395 subjects in vegetative state because of traumatic (63%), massive acute vascular (30%), or diffuse anoxic-hypoxic (7%) brain damage consecutively admitted to one dedicated unit during the years 1998-2008. Visual tracking was observed in 290 subjects (73.4%) and was already detectable within 50 days from brain injury in about 60% of post-traumatic or vascular subjects and 21% of anoxic-hypoxic patients. After 230 days of follow-up or more, it was observed in 89% and 88% of post-traumatic and vascular subjects and in 67% of anoxic-hypoxic patients. Rating with the Glasgow Outcome Scale (GOS) was better in those subjects with recovered visual tracking and inversely correlated with the time of reappearance in post-traumatic and vascular subjects; also the subjects with late recovery of eye tracking (230 days or more) had better GOS outcome than those without it. The observation of visual tracking reappearing in subjects in vegetative state would reflect recuperation of the brainstem-cortical interaction and overall brain functional organization that are thought to sustain consciousness and are interfered with by the "functional disconnection," resulting in the vegetative state. © 2011, Mary Ann Liebert, Inc. Source

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