title: Predictors of a nondiagnostic epilepsy monitoring study and yield of repeat study.
abstract: OBJECTIVE
  Failure to record typical events during long-term video/EEG monitoring (LTM) leaves the diagnosis uncertain. The purpose of this study was to analyze predictors of an initial nondiagnostic LTM study and to evaluate the yield of a repeat study.
  
  
  METHODS
  We reviewed all adult LTM studies performed at Vanderbilt University from January 2004 to June 2008. We identified 150 patients with no typical events on LTM and matched them with consecutive controls with typical events. We compared patient demographics, epilepsy risk factors, history of antiepileptic use/failures, and prior EEG and MRI results.
  
  
  RESULTS
  Of 2397 LTM studies, 380 (15.8%) failed to record typical events. Absence of epilepsy risk factors and normal outpatient EEG predicted this outcome. A repeat LTM study was successful in 18 of 45 patients (42%).
  
  
  CONCLUSIONS
  The prediction of a nondiagnostic LTM can help to reduce the cost of investigating spells of unknown nature.
authors.affiliation: Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232–2551, USA.
authors.forename: Althea A
authors.initials: AA
authors.lastname: Robinson
authors.forename: Nataria
authors.initials: N
authors.lastname: Pitiyanuvath
authors.forename: Bassel W
authors.initials: BW
authors.lastname: Abou-Khalil
authors.forename: Lily
authors.initials: L
authors.lastname: Wang
authors.forename: Yaping
authors.initials: Y
authors.lastname: Shi
authors.forename: Nabil J
authors.initials: NJ
authors.lastname: Azar
mesh_terms: D000328:Adult; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012307:Risk Factors; D014741:Video Recording