Surgical Prognostic Value of Epileptic Aura Based on History and Electrical Stimulation

We attempted to evaluate the surgical prognostic value of various types of aura in conjunction with the results of other presurgical evaluations in patients with an intracranial ictal onset zone confirmed by invasive studies and focal resection. We also attempted to determine how often the habitual auras could be elicited and to demonstrate the prognostic value of these stimulation-induced auras (SIAs).

We reviewed retrospectively the records of patients who had undergone intracranial electroencephalography evaluation and focal resective surgery for intractable partial epilepsy between 1995 and 2009. We identified the localizing value and prognostic value of the patients' auras. We correlated the resection of the area with SIA and surgical outcome.

Aura was reported in 225 out of 300 patients. Patients with medial temporal lobe epilepsy (TLE) or occipital lobe epilepsy had a higher chance of having aura. The presence of aura, medial TLE, hippocampal sclerosis on pathology, focal lesions on magnetic resonance imaging (MRI), and ipsilateral abnormality on fluorodeoxyglucose-positron emission tomography were significantly correlated with seizure-free outcome. The presence of auditory aura, parietal lobe epilepsy, multifocal epilepsy, and dual pathology was associated with poor outcomes. Multivariate analysis revealed that auditory aura, multifocal epilepsy, hippocampal sclerosis, and lesion on MRI were prognostic factors for intractable partial epilepsy. SIA was observed in 29 out of the 134 patients who had habitual aura on history. The degree of complete resection of the area with SIA was not related to seizure-free outcome.

The presence of aura favors good surgical outcome and certain types of aura, such as auditory aura, have poor prognostic value. SIA, which was encountered in 21.6% of patients, was not related to seizure-free outcome.