title: Clinical correlation and prognostic implication of periodic EEG patterns: A cohort study.
abstract: Despite increasing amounts of research on periodic discharges (PDs), large clinical studies regarding their prognostic value are lacking. The aim of the current study was to evaluate the clinical implications and prognostic value of PDs.
  
  
  
  In this single-center retrospective cohort study, we included patients who underwent electroencephalographic recording either during hospitalization or from our outpatient clinics. Demographic data, associated seizure events, use of antiepileptic drugs, and outcomes at discharge were analyzed. Multivariate logistic regression analysis was used to evaluate associations between clinical factors and functional outcomes.
  
  
  
  Four hundred and twenty patients were enrolled during a 17-year period, with a mean age of 66 years. The main etiologies included systemic infection (24%), anoxia (15%), and ischemic stroke (12%). Recent seizures were identified in 283 patients (67%), of whom 84 (30%) had status epilepticus. One hundred and fifty-four patients (37%) did not survive to hospital discharge. In multivariate analysis, old age (>65years; OR=2.55; 95% CI=1.57-4.16; P<0.001) was the strongest predictor of mortality, followed by systemic infection, anoxic encephalopathy, cefepime encephalopathy, and the occurrence of status epilepticus. Conversely, the use of antiepileptic drugs was negatively associated with mortality (OR=0.50; 95% CI=0.28-0.87; P=0.02).
  
  
  
  PDs were associated with high rates of comorbidities and recent seizures, while the use of antiepileptic drugs was associated with a lower rate of mortality.
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: srvhandow@gmail.com.
authors.forename: Han-Tao
authors.initials: HT
authors.lastname: Li
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: tonywu@cgmh.org.tw.
authors.forename: Tony
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Gastroenterology and Hepatology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: victor.wr.lin@gmail.com.
authors.forename: Wey-Ran
authors.initials: WR
authors.lastname: Lin
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: b101090151@tmu.edu.tw.
authors.forename: Wei-En Johnny
authors.initials: WJ
authors.lastname: Tseng
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: chang7656@gmail.com.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Chang
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: cheng-mei-yun@yahoo.com.tw.
authors.forename: Mei-Yun
authors.initials: MY
authors.lastname: Cheng
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: timshea@adm.cgmh.org.tw.
authors.forename: Hsiang-Yao
authors.initials: HY
authors.lastname: Hsieh
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: chiang.rex@gmail.com.
authors.forename: Hsing-I
authors.initials: HI
authors.lastname: Chiang
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: lysander@adm.cgmh.org.tw.
authors.forename: Chih-Hong
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: m7243@adm.cgmh.org.tw.
authors.forename: Bao-Luen
authors.initials: BL
authors.lastname: Chang
authors.affiliation: Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: siewna@adm.cgmh.org.tw.
authors.forename: Siew-Na
authors.initials: SN
authors.lastname: Lim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D004569:Electroencephalography / Q000379:methods* / Q000639:trends; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology*; D055815:Young Adult
keywords: Antiepileptic drugs; Functional outcome; Old age; Periodic discharges; Predictors