How long is long enough? The utility of prolonged inpatient video EEG monitoring

Is inpatient ictal video‐electroencephalographic monitoring mandatory in mesial temporal lobe epilepsy with unilateral hippocampal sclerosis? A prospective study

“…There is a strong association with neurological and psychiatric disorders, 30 and 5%-40% of patients with PNES also present epileptic seizures. 33 Therefore, long-term VEEG can help to identify PNES, but cannot exclude its existence. One study demonstrated that short-term VEEG (3-or 4-hour duration) have even higher yield for recording PNES than epileptic seizures.…”

A systematic review of suggestive seizure induction for the diagnosis of psychogenic nonepileptic seizures

“…In the study by Ribaï and colleagues the average VEEG duration was 4.6 days, and still 32% of PNES patients had inconclusive VEEG but positive SSI (Ribaï et al, 2006). One recent study specifically investigated the utility of longterm VEEG in the diagnosis of 150 patients with suspected PNES (Moseley et al, 2015). The authors calculated a cut-off at 5.5 days of VEEG, after which the length of stay was associated with an increased Page 11 of 26 A c c e p t e d M a n u s c r i p t 8 risk of being inconclusive; no such cut-off was seen in 333 patients with epilepsy (Moseley et al, 2015).…”

“…Although long-term VEEG is frequently referred to as the "gold standard", it is such only in terms of diagnostic confidence when positive, just as SSI is (LaFrance et al, 2013). A "gold standard" in terms of perfect (near 100%) sensitivity does not exist for PNES, since even long-term VEEG often remains inconclusive or negative in cases of suspected or confirmed PNES (Lancman et al, 1994;Moseley et al, 2015;Ribaï et al, 2006). Despite these and other methodological considerations (Lanska, 1994;Levine, 1994;Replogle et al, 2009) for the purpose of this review long-term VEEG was considered an adequate independent reference standard.…”

“…This could explain the short latency of habitual PNES during VEEG despite partly low seizure frequencies (Parra et al, 1998). If, however, the stressor is exogenous (e. g. conflicts with a family member or mental overload at work), a spontaneous attack might fail to occur in the relatively stressfree epilepsy monitoring unit despite reportedly high seizure frequencies (Moseley et al, 2015). To facilitate diagnosis an exogenous stressor (SSI) combined with a permissive attitude suggested by the examiner ("it is safe to have an attack here") would be needed.…”

“…One recent study specifically investigated the utility of longterm VEEG in the diagnosis of 150 patients with suspected PNES (Moseley et al, 2015). The authors calculated a cut-off at 5.5 days of VEEG, after which the length of stay was associated with an increased Page 11 of 26 A c c e p t e d M a n u s c r i p t 8 risk of being inconclusive; no such cut-off was seen in 333 patients with epilepsy (Moseley et al, 2015). In the study by Chen and colleagues, none of the patients who had an unsuccessful SSI (9/51, 18%) had a spontaneous event afterwards during VEEG of 3.5 days on average (Chen et al, 2011).…”