Physiologic pseudoseizures: an EEG case report of mistake in identity

The misdiagnosis of epilepsy may occur from the misinterpretation of a routine scalp EEG. Typically, interictal epileptiform discharges are misidentified on EEGs because of the overinterpretation of normal variants or variations in normal electrocerebral activity. Most reports of misinterpretation have arisen from patients diagnosed with psychogenic nonepileptic attacks using in-patient video-EEG monitoring. However, because seizures are rarely captured in the routine performance of EEG in the outpatient setting, ictal overinterpretation is much less likely to occur. However, some physiologic conditions may also occur with paroxysmal hypersynchronous patterns on EEG and lead to a misdiagnosis of epilepsy. We report an adult woman with untreated obstructive sleep apnea and major depressive disorder that was self-referred for the evaluation of seizures. Brief episodes of delayed responsiveness associated with prolonged reading demonstrated the "generalized paroxysmal pattern" that was misinterpreted as a seizure during routine EEG at an outside institution. Subsequently, in-patient video-EEG monitoring reproduced multiple nonepileptic physiologic paroxysmal hypersynchronous arousals after prolonged reading. Treatment of the underlying sleep apnea, psychologic support, and limited prolonged reading lead to remission of her nonepileptic "spells" and successful discontinuation of antiepileptic drugs.