Abstracts

RATIONALE: The elderly frequently present with vague or non-specific symptomatology which hinders establishing a definitive clinical diagnosis of epilepsy. In older patients diagnosed with new onset seizures, only 38% of routine EEGs show epileptiform activity. The clinical utility of ambulatory/extended EEG recordings have not been studied in this population. This project was undertaken to evaluate the usefulness of extended/ambulatory EEG recordings in the diagnostic work-up for possible epilepsy.
METHODS: The electrographic findings of 38 elderly patients participating in the VA Cooperative Study [pound]428 were evaluated. All patients had routine EEGs as part of their diagnostic work-up for possible seizures. In those with unclear clinical manifestations and whose EEGs were either normal or inconclusive, an ambulatory/extended EEG recording was obtained.
RESULTS: Mean age was 72 years (65-79); 95% males. Routine EEGs were normal in 34.2%, 50% had focal and/or generalized slowing, and 15.8% had clear epileptiform activity. Thirty-two (32) patients had EEGs that were either normal or had evidence of slowing. Of those, 20 patients had extended/ambulatory EEG recordings done. These extended EEGs increased the diagnostic yield by 50%. Of the 10 patients whose ambulatory EEGs confirmed the diagnosis of epilepsy, 4 presented with possible seizure, 2 with confusion, 2 with blackout spells, 1 with TIA, and 1 with cardiac arrhythmia.
CONCLUSIONS: Seizures in the elderly often have subtle manifestations which may delay diagnosis of epilepsy or result in a misdiagnosis. Extended/ambulatory EEGs in elderly patients with questionable diagnosis of epilepsy can significantly increase the diagnostic yield of electroencephalography. When feasible, extended/ambulatory EEGs should be completed in older patients with vague or nonspecific clinical manifestations whose routine EEGs are either normal or inconclusive.
Support: Veterans Affairs Cooperative Studies Program.