The appearance of an episode is one of the least reliable methods for diagnosing epilepsy. The entertainment industry has shown that actors convincingly can imitate seizures. Some patients are excellent actors. Additionally, the wide variety of behaviors seen during complex partial seizures grants great latitude to the appearance of a possible seizure. Chapter 3 lists a variety of behaviors observed in an epilepsy monitoring unit during seizures with documented concurrent EEG changes.
Although a variety of diagnostic strategies may be employed, beyond the history itself, video-EEG monitoring remains the most useful method for differentiating epileptic from nonepileptic events (76). Certain behaviors recognized since the days of Sir William Gowers (77) are unlikely to occur during an epileptic seizure. Video-EEG monitoring has been used extensively to catalog correlates of seizures with no EEG changes. Abrupt onset of unresponsiveness, thrashing and uncoordinated movements, rocking movements, and pelvic thrusting are particularly common in psy-chogenic seizures (28, 78-81).
Preservation of consciousness is impossible during a generalized tonic-clonic seizure. Patients who recall events or conversations transpiring during their generalized seizure are experiencing psychogenic or other nonepileptic episodes. This rule only applies to the period of diffusely generalized seizurelike activity, and it must be applied with caution. Many people with secondarily generalized epilepsy recall their auras or focal motor onsets. Rare cases exist in which preservation of awareness exists during bilateral tonic or clonic motor activity, presumably because of linked bilateral motor cortex seizure foci. Vague recollections of the postictal state also are physiologic. The definition of complex partial seizures requires only an alteration of consciousness, not its absence. Preservation of some awareness and (usually distorted) recall for events during a partial seizure does not rule out a diagnosis of epilepsy. Similarly, awareness and ability to recall is partially present at the start of absence seizures. Penry and associates (82) showed that stimuli presented within a few seconds after onset of EEG spike-wave discharges often were recalled; stimuli presented after more than 10 to 20 seconds of spike-waves were not.
Was this article helpful?