Provocative techniques should be used for the diagnosis of psychogenic nonepileptic seizures.
Many epilepsy centers use provocative techniques (inductions) during EEG-video monitoring to aid in the diagnosis of psychogenic nonepileptic seizures. Provocative techniques are not always necessary, and they should only be used when they help establish the diagnosis. There are several situations where inductions have significant advantages. When attacks do not occur spontaneously, provocative techniques can turn an inconclusive evaluation into a diagnostic one. Triggering an attack with induction can shorten the evaluation, decreasing its cost and reducing waiting time in the monitoring unit. Patients with infrequent episodes (that do not occur frequently enough to obtain a spontaneous event during monitoring) can be scheduled for a brief outpatient monitoring with induction. In clinical scenarios where symptoms are consistent with a ''simple partial" seizure, the very presence of suggestibility is in itself a very strong additional argument to support a psychogenic etiology. The arguments against inductions are mainly based on ethical concerns. While these concerns have some validity, they are, in the real world, far outweighed by the alternatives. It is far more unethical to not obtain a definitive diagnosis when it would be possible, since the consequences of perpetuating the wrong diagnosis are many and serious. Even with placebo the benefits far outweigh the very minor ethical theoretical concerns, and the use of placebo is not even necessary. When correctly performed and interpreted, the specificity of inductions is over 90%. All tests have limitations, with some false positives and false negatives. Like all other tests, inductions must be used appropriately and with awareness of their limitations.
Benbadis
Selim R
SR
Comprehensive Epilepsy Program, Department of Neurology, University of South Florida and Tampa General Hospital, Tampa, FL, USA. sbenbadi@health.usf.edu
D000792:Angiography; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000009:adverse effects*; D004569:Electroencephalography; D004827:Epilepsy / Q000150:complications / Q000175:diagnosis*; D006403:Hematologic Tests; D006801:Humans; D008279:Magnetic Resonance Imaging; D008991:Monitoring, Physiologic / Q000009:adverse effects; D011602:Psychophysiologic Disorders / Q000150:complications / Q000175:diagnosis*; D012680:Sensitivity and Specificity