title: Asymmetric POSTS associated with unilateral EEG abnormalities.
abstract: OBJECTIVE
  Positive occipital sharp transient of the sleep (POSTS) are considered a normal variant of non-REM sleep EEG. We describe a small series of patients with asymmetric POSTS and ipsilateral abnormal EEG findings.
  
  
  METHODS
  Over a period of 30 weeks, we prospectively observed five consecutive subjects with strictly unilateral POSTS associated with ispilateral electrographic abnormalities. They represent 0.4% of all EEG performed over the same time lapse (5/1130), including inpatients, outpatients and long-term monitoring.
  
  
  RESULTS
  Four women and one boy suffering from epileptic seizures (aged 7-76 years old) had unilateral POSTS, occurring only on the right side, during light sleep. They also presented ipsilateral epileptiform abnormalities.
  
  
  CONCLUSIONS
  The fact that POSTS were asymmetric and found only on the same side as the abnormalities raises the question whether these transients should still be considered physiological or could be interpreted at times as markers of underlying electrical abnormalities, pointing to an increased cortical excitability on the more active side. Although larger samples are needed to confirm our preliminary results, this case study questions the interpretation of POSTS as a uniformly normal variant.
authors.affiliation: Service de neurologie, université de Lausanne, CHU Vaudois, Lausanne, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Aybek
authors.forename: M
authors.initials: M
authors.lastname: Maeder-Ingvar
authors.forename: P-A
authors.initials: PA
authors.lastname: Despland
authors.forename: A-O
authors.initials: AO
authors.lastname: Rossetti
mesh_terms: D000328:Adult; D000368:Aged; D001569:Benzodiazepines / Q000009:adverse effects; D002648:Child; D004292:Dominance, Cerebral; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000503:physiopathology; D004827:Epilepsy / Q000503:physiopathology*; D017034:Epilepsy, Frontal Lobe / Q000503:physiopathology; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000503:physiopathology; D008297:Male; D009103:Multiple Sclerosis / Q000503:physiopathology; D009778:Occipital Lobe / Q000503:physiopathology; D011446:Prospective Studies; D020919:Sleep Disorders, Intrinsic / Q000209:etiology / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology; D055815:Young Adult
chemical_list: D001569:Benzodiazepines