The Use of Placebo as a Provocative Test in the Diagnosis of Psychogenic Non Epileptic Seizures
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The Use of Placebo as a Provocative Test in the Diagnosis of Psychogenic Non Epileptic Seizures Henda Foreid & Carla Bentes & José Pimentel
Received: 15 September 2009 / Accepted: 6 January 2010 / Published online: 6 March 2010 # Springer Science+Business Media B.V. 2010
Abstract Psychogenic non epileptic seizures (PNES) are clinical events of psychological nature. Videoelectroencephalography monitoring (V-EEGM) is a valuable method for the diagnosis of PNES and may be combined with provocative tests to induce seizures. The use of placebo in provocative tests for the diagnosis of PNES is controversial because of associated deception, and contrasts with the use of truly decreasing epileptogenic threshold techniques such as hyperventilation and photo stimulation. We present a clinical case of a pregnant woman with a past history of refractory epilepsy, admitted in the obstetric department due to unremitting seizures. In this clinical context, non-deceiving provocative tests such as hyperventilation and photo stimulation could be potentially harmful, nevertheless, the use of intravenous saline injection presented as a safer alternative to diagnose PNES and hence obviate an urgent caesarean. This case illustrates a disproportionate risk of causing harm when telling the truth, in comparison with the benefit of avoiding such risk, H. Foreid (*) : C. Bentes EEG-Sleep Laboratory, Neurology Department, CHLN-Hospital de Santa Maria, Av. Egas Moniz, 1649-035 Lisbon, Portugal e-mail: [email protected] H. Foreid : C. Bentes : J. Pimentel Institute of Molecular Medicine, Lisbon Faculty of Medicine, Lisbon, Portugal
although deceiving the patient. This is a clinical example of how considerations concerning the use of placebo must be evaluated in an individual basis. Keywords Psychogenic non epileptic seizures . Videoelectroencephalography monitoring . Provocative tests
Introduction Psychogenic non epileptic seizures (PNES) are paroxysmal episodes that may resemble epileptic seizures but does not result from brain electric discharges, instead, PNES have a psychological origin classified as somatoform disorder in DSM IV [1, 2]. Video-electroencephalography (V-EEG) is the best method for the diagnosis of PNES, allowing a definite diagnosis in nearly all cases by the demonstration that neither a change in the EEG occurs during the clinical event, nor the clinical episode is consistent with seizures unaccompanied by EEG changes [3, 4]. For a prompted diagnosis V-EEGM may be complemented with provocative tests which increase the probability for a clinical event to occur [4–7]. Placebo have been used for the diagnosis of PNES, but not without significant ethical discussion concerning the associated deception. In an attempt to obviate such ethical issues, the use of hyperventilation and photic stimulation after an informed consent given by the patient was advocated as preferable, as a placebo substance is not used [8–10]. We present a
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clinical case of a 30 week pregnant woman in whom a diagnosis of PNES
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