title: Diagnostic yield of ambulatory EEGs in the elderly.
abstract: The diagnostic yield of ambulatory EEG in the elderly is not known. We sought to determine diagnostic yield and identify factors predicting diagnostic findings in this elderly population.
  
  
  
  We reviewed 156 consecutive 24-72h ambulatory EEGs performed on patients aged 60 or older.
  
  
  
  Of the 156 studies, 58 studies (37%) revealed potentially diagnostic findings: either epileptiform discharges, an epileptic seizure, or a typical nonepileptic event. Focal slowing on routine EEG predicted epileptiform abnormalities on ambulatory EEG with an odds ratio of 4.0 (95% CI 1.7-9.7, p=0.002). Age, the presence of a focal lesion on MRI, and duration of ambulatory EEG failed to predict epileptiform abnormalities on ambulatory EEG. Duration of ambulatory EEG predicted capture of a typical nonepileptic event with an odds ratio of 2.7 (95% CI 1.3-5.7, p=0.009) for every additional day of study duration.
  
  
  
  Focal slowing on routine EEGs may warrant an ambulatory EEG in the setting of diagnostic uncertainty. Longer ambulatory EEGs have a higher yield in capturing patients' typical non-epileptic events, and should be considered in patients where nonepileptic events are a likely diagnostic possibility.
  
  
  
  These findings offer guidance in the use of ambulatory EEGs in the elderly.
authors.affiliation: Department of Neurology, The Edward B. Bromfield Epilepsy Program, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Electronic address: btolchin@partners.org.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tolchin
authors.affiliation: Department of Neurology, The Edward B. Bromfield Epilepsy Program, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Electronic address: jlee38@partners.org.
authors.forename: Jong Woo
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Neurology, The Edward B. Bromfield Epilepsy Program, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Electronic address: mpavlova@bwh.harvard.edu.
authors.forename: Milena
authors.initials: M
authors.lastname: Pavlova
authors.affiliation: Department of Neurology, The Edward B. Bromfield Epilepsy Program, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Electronic address: bdworetzky@partners.org.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Dworetzky
authors.affiliation: Department of Neurology, The Edward B. Bromfield Epilepsy Program, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. Electronic address: rsarkis@partners.org.
authors.forename: Rani A
authors.initials: RA
authors.lastname: Sarkis
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods* / Q000639:trends; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods* / Q000639:trends; D012189:Retrospective Studies
keywords: Diagnosis; EEG monitoring; Epilepsy; Epileptiform discharges; Geriatric; Seizure