title: Permutation entropy of scalp EEG: a tool to investigate epilepsies: suggestions from absence epilepsies.
abstract: OBJECTIVE
  We used permutation entropy (PE) to disclose abnormalities of cerebral activity in patients with typical absences (TAs).
  
  
  METHODS
  We evaluated 24 EEG of TA patients and 40 EEG of healthy subjects. PE was estimated channel by channel, with electrodes being divided into high-PE cluster (high randomness), low-PE cluster (low randomness), and neutral cluster. We compared PE between EEG of patients and controls, and between interictal and ictal EEG of patients.
  
  
  RESULTS
  Patients showed a recurrent behavior of PE topography, with anterior brain regions constantly associated to high PE levels and posterior brain regions constantly associated to low PE levels, during both interictal and ictal phases. On the contrary, healthy controls had a random distribution of PE topography.
  
  
  CONCLUSIONS
  In patients with TAs, a higher randomness in fronto-temporal areas and a lower randomness in posterior areas occur during both interictal and ictal phases. Such abnormalities are in keeping with evidences from different morphological and functional studies showing multifocal brain changes in TA patients.
  
  
  CONCLUSIONS
  PE seems to be a useful tool to disclose abnormalities of cerebral electric activity not revealed by conventional EEG recordings, opening interesting prospective for future studies.
authors.affiliation: Magna Græcia University, Catanzaro, Italy; Regional Epilepsy Centre, "Bianchi-Melacrino-Morelli" Hospital, Reggio Calabria, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Ferlazzo
authors.affiliation: University Mediterranea of Reggio Calabria, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Mammone
authors.affiliation: Regional Epilepsy Centre, "Bianchi-Melacrino-Morelli" Hospital, Reggio Calabria, Italy.
authors.forename: Vittoria
authors.initials: V
authors.lastname: Cianci
authors.affiliation: Magna Græcia University, Catanzaro, Italy; Regional Epilepsy Centre, "Bianchi-Melacrino-Morelli" Hospital, Reggio Calabria, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Gasparini
authors.affiliation: Magna Græcia University, Catanzaro, Italy; National Research Council, Piano Lago di Mangone, Cosenza, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gambardella
authors.affiliation: Magna Græcia University, Catanzaro, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Labate
authors.affiliation: Regional Epilepsy Centre, "Bianchi-Melacrino-Morelli" Hospital, Reggio Calabria, Italy.
authors.forename: Maria Adele
authors.initials: MA
authors.lastname: Latella
authors.affiliation: Institute of Neurology, University of Catania, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Sofia
authors.affiliation: Unit of Neurology and Clinical Neurophysiopathology, Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Enna, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Elia
authors.affiliation: University Mediterranea of Reggio Calabria, Italy.
authors.forename: Francesco Carlo
authors.initials: FC
authors.lastname: Morabito
authors.affiliation: Magna Græcia University, Catanzaro, Italy; Regional Epilepsy Centre, "Bianchi-Melacrino-Morelli" Hospital, Reggio Calabria, Italy. Electronic address: u.aguglia@tin.it.
authors.forename: Umberto
authors.initials: U
authors.lastname: Aguglia
mesh_terms: D000293:Adolescent; D001921:Brain / Q000503:physiopathology; D002648:Child; D004569:Electroencephalography / Q000379:methods*; D019277:Entropy; D004832:Epilepsy, Absence / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012535:Scalp
keywords: Absences; Brain topography; EEG; Permutation entropy