Lateralized interictal epileptiform discharges during rapid eye movement sleep correlate with epileptogenic hemisphere in children with intractable epilepsy secondary to tuberous sclerosis complex

Abstract

SUMMARYPurpose: We assessed lateralization of interictal epileptiform discharges (IEDs) in children with intractable epilepsy secondary to tuberous sclerosis complexes (TSCs) during rapid eye movement sleep (R), compared with non-rapid eye movement sleep (NR) and wakefulness (W), to determine epileptogenicity of R-IEDs. Methods: We retrospectively studied 23 children with TSC, who underwent prolonged scalp video-electroencephalography (EEG) and magnetic resonance imaging (MRI). We determined the lateralization of ictal EEG, clinical semiology, and the largest tuber on MRI. We analyzed a minimum of 100 IEDs during R, NR, and W to classify right/left/generalized spikes to compare the lateralization with ictal EEG, clinical semiology, and MRI.

The role of sleep electroencephalography in patients with new onset epilepsy

“…For each 10 s segment, eyes were opened and closed for 5 s each. The trains were performed at frequencies of 1, 2, 4, 6,8,10,12,13,14,15,16,17,18,20,25,30,50 and 60 Hz. At least 30 min of artifact-free signals were recorded.…”

“…Additionally, increased lateralizing and localizing values were reported for interictal epileptiform discharges occurring in NREM (non-rapid eye movement) sleep stages [7,9,12]. Precipitation of epileptic activities and seizures upon sleep and during sleep deprivation were reported in patients with confirmed epilepsy [13,14].…”

High frequency oscillations are less frequent but more specific to epileptogenicity during rapid eye movement sleep

“…On the other hand, a significant number of epileptic HFOs co-occur with epileptic spikes and fast waves (Wang et al, 2013). Interictal epileptic spikes become infrequent (Sammaritano et al, 1991;Malow et al, 1997Malow et al, , 1998, but the spiking area is localized in the primary epileptogenic areas during REM in patients with partial epilepsy (Lieb et al, 1980;Ochi et al, 2011). Although the effect of sleep stage on epileptic HFOs is not clearly understood, it is possible that physiological HFOs are well suppressed but epileptic HFOs are relatively maintained together with epileptic spikes and localized to the epileptogenic zone during REM.…”

Clinical MEG Analyses for Children with Intractable Epilepsy

“…The fast activity is one sign of the epileptogenic zone (Kobayashi et al, 2004;Yamazsaki et al, 2008). Predominantly lateralized or localized interictal spikes during REM sleep also suggest the epileptogenic hemisphere (Samalitano et al, 1991;Ochi et al, 2011). When we analyze MEG data, we always compare the scalp video-EEG and MEG to recognize the characteristics of the interictal spikes, seizure onset zone and seizure semiology for the clinical interpretation of the MEG result.…”

“…Frontal lobe epilepsy frequently presents with secondarily bilateral synchronized epileptiform discharges (Akiyama et al, 2011). MEG dipoles can be estimated at the earliest peak of spikes before generalization in the spike complex which should have >1sec interval during continuous spike and waves (see Table 1; 1.3 & 1.4).…”