title: Brief potentially ictal rhythmic discharges in critically ill adults.
abstract: OBJECTIVE
  Brief potentially ictal rhythmic discharges, termed B(I)RDs, have been described mainly in neonates, and their significance in adults remains unclear.
  
  
  OBJECTIVE
  To describe the incidence of B(I)RDs in critically ill patients and investigate their association with seizures and outcome.
  
  
  METHODS
  We reviewed the records of prospectively identified patients with B(I)RDs and patients serving as controls matched for age (±5 years) and primary diagnosis.
  
  
  METHODS
  The prevalence of seizures during continuous electroencephalography and functional outcome, as measured by the Glasgow Outcome Scale, were determined.
  
  
  RESULTS
  We identified B(I)RDs in 20 patients (2%). The pattern most often consisted of very brief (1-3 seconds) runs of sharply contoured theta activity without obvious evolution. All patients with B(I)RDs had cerebral injury, and in cases with a single focal lesion (11 [55%]), B(I)RDs were localized in the same region in all but 2 cases (18%). Patients with B(I)RDs were more likely to have seizures during continuous electroencephalography than were patients without B(I)RDs (15 of 20 [75%] vs 10 of 40 [25%]; P < .001), and 9 patients with B(I)RDs (60%) had only subclinical seizures. Brief potentially ictal rhythmic discharges were identified before seizures in all but 1 case (93%) and ceased in all 12 cases (80%) in which seizures were controlled. Patients with B(I)RDs tended to have a worse outcome than controls (16 [80%] vs 25 [63%]); however, this finding was not statistically significant.
  
  
  CONCLUSIONS
  Brief potentially ictal rhythmic discharges in critically ill patients are associated with a high prevalence (75%) of electrographic seizures and might serve as an early predictor of seizures during subsequent monitoring. A larger prospective study is needed to better understand their clinical and prognostic significance.
authors.affiliation: Comprehensive Epilepsy Center and Division of Clinical Neurophysiology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Ji Yeoun
authors.initials: JY
authors.lastname: Yoo
authors.affiliation: Comprehensive Epilepsy Center and Division of Clinical Neurophysiology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Nishi
authors.initials: N
authors.lastname: Rampal
authors.affiliation: Comprehensive Epilepsy Center and Division of Clinical Neurophysiology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Ognen A
authors.initials: OA
authors.lastname: Petroff
authors.affiliation: Comprehensive Epilepsy Center and Division of Clinical Neurophysiology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.affiliation: Comprehensive Epilepsy Center and Division of Clinical Neurophysiology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gaspard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D016638:Critical Illness; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D012640:Seizures / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult