The diagnosis of pseudoseizures.

Increasing experience with intensive monitoring of patients with intractable seizures has shown that a significant number of patients presents with pseudoseizures (psychogenic seizures). While in a majority of the patients differential diagnosis should be obvious, in some patients diagnostic error may occur. This is the case if the physician is unfamiliar with uncommon seizures, if the patient presents with atypical or bizarre attacks, and if interictal and/or ictal EEG are normal. Comparative studies of patients with true convulsive seizures and patients with pseudoseizures have revealed some 'typical' ictal features of pseudoseizures. Of these, longer ictal duration, less stereotypy, asynchronous extremity movements, atypical vocalization, alternating head movements and pelvic thrusting are the most characteristic. Many exceptions exist, however, since many patients with complex partial seizures (mostly of frontal origin) may present with similar ictal features. The final diagnosis of pseudoseizures is based upon integration of numerous data including careful seizure history, results of intensive video EEG monitoring and electroclinical correlation by experienced observers. Psychiatric and personality examination, different techniques of suggestion and determination of serum prolactin may provide additional diagnostic evidence.