title: Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients.
abstract: This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.
authors.affiliation: Department of Anesthesia and Intensive Care, Neurophysiology, Treviso Regional Hospital, Piazzale Ospedale 1, Treviso, Italy. pzanatta@mac.com
authors.forename: Paolo
authors.initials: P
authors.lastname: Zanatta
authors.forename: Simone
authors.initials: S
authors.lastname: Messerotti Benvenuti
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Baldanzi
authors.forename: Matteo
authors.initials: M
authors.lastname: Bendini
authors.forename: Marsilio
authors.initials: M
authors.lastname: Saccavini
authors.forename: Wadih
authors.initials: W
authors.lastname: Tamari
authors.forename: Daniela
authors.initials: D
authors.lastname: Palomba
authors.forename: Enrico
authors.initials: E
authors.lastname: Bosco
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications; D000368:Aged; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D020127:Recovery of Function