What is the diagnostic value of repeating a nondiagnostic video-EEG study?

Repeat video-EEG (VEEG) may increase diagnostic yield, but the test is resource intensive, time-consuming, and expensive and poses some potential risks to patients. It is also relatively common to monitor a patient for several days without capturing any clinical events. The purpose of this study was to determine the diagnostic value of repeat admissions for VEEG and to determine if the commonly available clinical information could predict the diagnostic outcome, "diagnostic" or "nondiagnostic," of a repeat study. A study was deemed diagnostic if the admission resulted in a definitive diagnosis of the patient's typical events. The authors retrospectively reviewed the charts of 3,727 patients completing scalp VEEG at the University of Alabama at Birmingham Epilepsy Center from 2002 to 2009. Minors, mentally retarded patients, and patients readmitted for surgical procedures or presurgical localization were excluded. Single and multiple regressions were used to determine if any of the parameters could predict the diagnostic outcome of a repeat VEEG study. Only younger age was independently predictive of a diagnostic readmission (P < 0.05), while longer total duration of monitoring was suggestive (P = 0.07). A repeat VEEG study was useful in 55.2% of patients, most of whom were diagnosed after only 1 additional admission. In the patient population studied, 82.4% were diagnosed on the first admission (2,622 of 3,183), 52.9% on the second (46 of 87), and 40% on the third (2 of 5). Repeat VEEG admissions are useful, and clinical expertise may be the best tool for planning potential readmissions.