title: Is interictal EEG activity a biomarker for mood disorders in temporal lobe epilepsy?
abstract: OBJECTIVE
  Psychiatric comorbidities are frequent in temporal lobe epilepsy (TLE), and symptoms of these comorbidities may be related to epilepsy activity. Here we evaluated interictal EEG activity in TLE patients with or without psychiatric comorbidities.
  
  
  METHODS
  A cohort study of 78 patients with TLE, with evaluation of wake/sleep interictal scalp EEG. All subjects were submitted to a psychiatric structured clinical interview (SCID) for the diagnosis of lifetime psychiatric comorbidities. Three major diagnostic categories were studied: mood disorders, anxiety disorders, and psychosis. We then evaluated differences in interictal EEG activity between patients with and without these psychiatric comorbidities.
  
  
  RESULTS
  Infrequent EEG interictal spikes, defined as less than one event per minute, were significantly associated with mood disorders in TLE (p=0.02).
  
  
  CONCLUSIONS
  Low intensity seizure disorder has been associated with a decrease in interictal EEG discharges and with an increase in psychiatric symptoms in TLE, a phenomenon known as forced normalization. In our study, we observed a low interictal spike frequency on EEG in TLE patients with mood disorders.
  
  
  CONCLUSIONS
  A low spike index might be a neurophysiological marker for depression in temporal lobe epilepsy.
authors.affiliation: Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil. Electronic address: jabragatti@terra.com.br.
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Bragatti
authors.affiliation: Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil.
authors.forename: Carolina Machado
authors.initials: CM
authors.lastname: Torres
authors.affiliation: Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil.
authors.forename: Pedro Abrahim
authors.initials: PA
authors.lastname: Cherubini
authors.affiliation: Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clinicas de Porto Alegre, Brazil.
authors.forename: Sandra
authors.initials: S
authors.lastname: Leistner-Segal
authors.affiliation: Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil.
authors.forename: Marino Muxfeldt
authors.initials: MM
authors.lastname: Bianchin
mesh_terms: D000328:Adult; D015415:Biomarkers; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D015331:Cohort Studies; D015897:Comorbidity; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D015415:Biomarkers
keywords: EEG; Epilepsy; Interictal epileptiform discharges; Mood disorders; Psychiatric comorbidities