Diagnostic Accuracy of Ambulatory EEG vs Routine EEG in Patients With First Single Unprovoked Seizure

Area of Science:

• Clinical Neurology
• Epileptology
• Diagnostic Imaging

Background:

• First single unprovoked seizure (FSUS) diagnosis requires accurate detection of interictal epileptiform discharges (IEDs).
• Routine EEG (rEEG) and repetitive rEEG have limitations in capturing these critical diagnostic markers.

Purpose of the Study:

• To compare the diagnostic accuracy of ambulatory EEG (aEEG) versus routine EEG (rEEG) and repetitive rEEG in detecting IEDs/seizures.
• To assess the association between aEEG findings and seizure recurrence risk in FSUS patients.

Main Methods:

• Prospective evaluation of 100 consecutive FSUS patients undergoing sequential rEEG, second rEEG, and aEEG.
• Diagnostic accuracy metrics (sensitivity, specificity, PPV, NPV, likelihood ratios, ROC analysis) were calculated.
• Seizure recurrence was monitored for 52 weeks using life tables and Cox proportional hazard models.

Main Results:

• Ambulatory EEG demonstrated significantly higher sensitivity (72%) for IED/seizure detection compared to first rEEG (11%) and second rEEG (22%).
• aEEG showed superior diagnostic performance (AUC: 0.85) over rEEG modalities (AUC: 0.56–0.60).
• IEDs/seizures detected by aEEG were associated with over a threefold increased hazard of seizure recurrence.

Conclusions:

• Ambulatory EEG offers superior diagnostic accuracy for detecting IEDs/seizures in FSUS patients compared to standard EEG methods.
• aEEG findings in FSUS patients are predictive of an elevated risk for future seizure recurrence.