Usefulness of prolonged video-EEG monitoring and provocative procedure with saline injection for the diagnosis of non epileptic seizures of psychogenic origin.

OBJECTIVES

To assess the usefulness of long term video-EEG monitoring (VEEGM) and intravenous injection of saline solution (IVISS) for the diagnosis of non epileptic seizures of psychogenic origin (PNES).

BACKGROUND

PNES are common among patients referred to an epilepsy center. Long term VEEGM remains the gold standard method for assessing the correct diagnosis. However, spontaneous PNES do not always occur during VEEGM, and a provocative test is often required. Although IVISS is the most commonly performed method, its usefulness is still debated.

METHODS

We performed a long term VEEGM and an IVISS test the last day of the monitoring to each patient admitted to the Epilepsy Monitoring Unit of Erasme Hospital, Brussels, between October 2001 and February 2005 for suspicion of PNES. Patient charts were retrospectively reviewed.

RESULTS

Of a total of 138 patients admitted to our center, 28 (20.3%) were referred for suspicion of PNES. There were 7 men and 21 women with a mean age of 35 years. Twenty-one patients (75%) had PNES during the VEEGM. Ten patients (36 %) had spontaneous PNES and positive IVISS. Nine patients (32 %) had no spontaneous PNES but a positive IVISS. Two patients (7 %) had spontaneous PNES and a negative IVISS. Among patients with PNES, 8 had also epileptic findings.

CONCLUSION

IVISS is a useful diagnostic tool since it was the only way to confirm the diagnosis of PNES in 32% of our patients. We suggest that investigation for the diagnosis of PNES should always include both a prolonged VEEGM and an IVISS test.