title: Predictors of seizure occurrence in children undergoing pre-surgical monitoring.
abstract: OBJECTIVE
  Long-Term-Monitoring (LTM) is a valuable tool for seizure localization/lateralization among children with refractory-epilepsy undergoing pre-surgical-monitoring. The aim of this study was to examine the factors predicting occurrence of single/multiple seizures in children undergoing pre-surgical monitoring in the LTM unit.
  
  
  METHODS
  Chart review was done on 95 consecutive admissions on 92 children (40 females) admitted to the LTM-unit for pre-surgical workup. Relationship between occurrence of multiple (≥ 3) seizures and factors such as home seizure-frequency, demographics, MRI-lesions/seizure-type and localization/AED usage/neurological-exam/epilepsy-duration was evaluated by logistic-regression and survival-analysis. Home seizure-frequency was further categorized into low (up-to 1/month), medium (up-to 1/week) and high (>1/week) and relationship of these categories to the occurrence of multiple seizures was evaluated. Mean length of stay was 5.24 days in all 3 groups.
  
  
  RESULTS
  Home seizure frequency was the only factor predicting the occurrence of single/multiple seizures in children undergoing presurgical workup. Other factors (age/sex/MRI-lesions/seizure-type and localization/AED-usage/neurological-exam/epilepsy-duration) did not affect occurrence of single/multiple seizures or time-to-occurrence of first/second seizure. Analysis of the home-seizure frequency categories revealed that 98% admissions in high-frequency, 94% in the medium, and 77% in low-frequency group had at-least 1 seizure recorded during the monitoring. Odds of first-seizure increased in high vs. low-frequency group (p=0.01). Eighty-nine percent admissions in high-frequency, 78% in medium frequency, versus 50% in low-frequency group had ≥ 3 seizures. The odds of having ≥ 3 seizures increased in high-frequency (p=0.0005) and in medium-frequency (p=0.007), compared to low-frequency group. Mean time-to-first-seizure was 2.7 days in low-frequency, 2.1 days in medium, and 2 days in high-frequency group. Time-to-first-seizure in high and medium-frequency was less than in low-frequency group (p<0.0014 and p=0.038).
  
  
  CONCLUSIONS
  Majority of the admissions (92%) admitted to the LTM-unit for pre-surgical workup had at-least one seizure during a mean length of stay of 5.24 days. Home seizure-frequency was the only predictor influencing occurrence of single/multiple seizures in the LTM unit. Patients with low seizure-frequency are at risk for completing the monitoring with less than the optimum number (<3) of seizures captured.
authors.affiliation: Division of Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States. chellamani.harini@childrens.harvard.edu
authors.forename: Chellamani
authors.initials: C
authors.lastname: Harini
authors.forename: Kanwaljit
authors.initials: K
authors.lastname: Singh
authors.forename: Masanori
authors.initials: M
authors.lastname: Takeoka
authors.forename: Isha
authors.initials: I
authors.lastname: Parulkar
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Bergin
authors.forename: Tobias
authors.initials: T
authors.lastname: Loddenkemper
authors.forename: Sanjeev V
authors.initials: SV
authors.lastname: Kothare
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D009460:Neurologic Examination; D011300:Preoperative Care; D057234:Preoperative Period; D012307:Risk Factors; D012640:Seizures / Q000175:diagnosis* / Q000601:surgery
keywords: Pre-surgical monitoring; Predictors of seizure occurrence; Seizure frequency