How valuable is inpatient electroencephalogram for medical decision-making?

Background The electroencephalogram (EEG) can support the diagnosis of epilepsy, diagnose nonconvulsive status epilepticus and aid in the classification of epileptic seizures. Its contribution to the diagnosis of other medical conditions or to decision-making in other clinical situations was not established. Practically, EEG laboratories frequently encounter EEG referrals that are not based on current recommendations. Objectives To assess the value of inpatient EEG in medical decision-making. Methods We retrospectively reviewed the inpatient computerized medical information management system and the EEG laboratory computerized database for all adult inpatient standard, sleep-deprived and bedside EEGs performed during a one-year period. Change in diagnosis and/or treatment and the clinical justification for ordering an EEG recording were determined. Results The study group included 584 patients, 313 (54%) men, aged 55.5 +/- 20.8 years (range 18-95 years). The EEG was clinically justified in 372 (63.7%) and led to change in diagnosis and/or treatment in 47 (8%) patients. These patients were significantly more likely to be admitted to the neurology department (P = 0 . 033), have an admission and discharge diagnosis of seizure or epilepsy (P = 0.0001), have a clinically justified EEG (P = 0.0001) and have an EEG recording with electrographic seizures (P = 0.0001), interictal epileptiform discharges (P = 0.0001) and background abnormalities (P = 0.003). Conclusions Inpatient EEG can mostly contribute to diagnosis and treatment in patients with a seizure or epilepsy. An informed use of the EEG can increase its yield and reduce the number of unnecessary referrals, thus shortening waiting time and enabling earlier diagnosis and treatment in yet undiagnosed patients.