Predictive Value of Interictal Epileptiform Discharges During Non‐REM Sleep on Scalp EEG Recordings for the Lateralization of Epileptogenesis

Adachi, Naoto; Alarcón, Gonzalo; Binnie, C.D.; Elwes, Robert; Polkey, Charles E.; Reynolds, E. H.

doi:10.1111/j.1528-1157.1998.tb01431.x

Cited by 68 publications

(38 citation statements)

References 24 publications

(23 reference statements)

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“…In the context of other information (e.g., ictal recordings, neuroimaging studies), these sleep-activated IED foci may provide useful clinical information in the presurgical evaluation of patients refractory to AEDs. Adachi et al (28) examined the predictive value of NREM sleep recorded on routine EEGs in 83 subjects with temporal lobe epilepsy who were seizure free for > I year. They reported that the accuracy of EEG recordings for prediction of lateralization increased from 51.8% during waking to 78.3% during sleep, suggesting that IEDs occurring in non-REM sleep provide more accurage information for lateralization of epileptogenesis than do those occurring during waking (28).…”

Section: Discussionmentioning

confidence: 99%

“…Adachi et al (28) examined the predictive value of NREM sleep recorded on routine EEGs in 83 subjects with temporal lobe epilepsy who were seizure free for > I year. They reported that the accuracy of EEG recordings for prediction of lateralization increased from 51.8% during waking to 78.3% during sleep, suggesting that IEDs occurring in non-REM sleep provide more accurage information for lateralization of epileptogenesis than do those occurring during waking (28). In contrast, Sammaritano et al In summary, our findings support the hypothesis that processes related to NREM sleep state and to the deepening of NREM sleep activate focal IEDs.…”

Section: Discussionmentioning

confidence: 99%

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Interictal Spiking Increases with Sleep Depth in Temporal Lobe Epilepsy

et al. 1998

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Summary:Purpose: To test the hypothesis that deepening sleep activates focal interictal epileptiform discharges (IEDs), we performed EEG-polysomnography in 21 subjects with medically refractory temporal lobe epilepsy.Methods: At the time of study, subjects were seizure-free for 224 h and were taking stable doses of antiepileptic medications (AEDs). Sleep depth was measured by log delta power (LDP). Visual sleep scoring and visual detection of IEDs also were performed. Logistic-regression analyses of IED occurrence in relation to LDP were carried out for two groups of subjects, nine with frequent IEDs (group 1) and 12 with rare IEDs (group 2).Results: The LDP differentiated visually scored non-rapid eye movement (NREM) sleep stages (p = 0.QOOl). The IEDs were most frequent in NREM stages 3/4 and least frequent in Non-rapid-eye-movement (NREM) sleep activates interictal epileptiform discharges (IEDs) in both partial and generalized epilepsy syndromes (1-4). In contrast, rapideye-movement (REM) sleep suppresses epileptiform discharges. Experimental models also demonstrated that epileptic foci are modulated by sleep (5,6). The activating role of NREM sleep on epileptic cortex has been attributed to increased neuronal synchronization within thalamocortical projection neurons (7).The depth of NREM sleep may affect epileptic activity. Several visually scored studies of surface or intracranial recordings in subjects with partial epilepsy demonstrated that delta NREM sleep (stages 3 and 4) activates IEDs preferentially compared with stages 1 and 2 (8-10). By using log delta power ( NREM sleep, IEDs were more likely to occur: (a) at higher levels of LDP; (b) on the ascending limb of LDP; and (c) with more rapid increases in LDP. The IED frequency per minute was 4.6 times higher in NREM than in REM sleep and diminished with time from sleep onset. These results suggested that focal IEDs were activated by deepening sleep. To extend these preliminary findings, we analyzed the relation of IEDs to sleep depth in 21 additional subjects recruited from a group of patients undergoing evaluation for epilepsy surgery. These subjects (a) all had medically refractory complex partial seizures of temporal lobe origin with or without secondary generalization; (b) had a variety of pathologic lesions, including mesial temporal sclerosis, gliomas, and cavernous angiomas, and (c) varied widely in the number of IEDs recorded. SUBJECTS AND METHODS SubjectsBetween December 1995 and February 1997, all subjects undergoing presurgical evaluation in the University of Michigan Epilepsy Laboratory and meeting criteria were asked to participate in the study, and 57% agreed, 1309

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Interictal Spiking Increases with Sleep Depth in Temporal Lobe Epilepsy

et al. 1998

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“…Unfortunately, only 5 1 % of their subjects had IEDs during REM sleep, compared with 68% of subjects with IEDs in wakefulness and 100% of subjects with IEDs in NREM sleep. Adachi and coworkers (19) examined the predictive value of NREM sleep recorded on routine EEGs in 83 subjects with temporal lobe epilepsy who were seizure free for >1 year. They reported that the accuracy of EEG recordings for prediction of lateralization increased from 51.8% during waking to 78.3% during sleep, and suggested that IEDs occurring in NREM sleep provide more accurate information for lateralization of epileptogenesis than do those occurring in wakefulness.…”

Section: Discussionmentioning

confidence: 99%

Lateralizing Value of Interictal Spikes on Overnight Sleep‐EEG Studies in Temporal Lobe Epilepsy

Malow¹,

Selwa²,

Ross

et al. 1999

Epilepsia

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Summary:Purpose: To determine the lateralizing value of interictal epileptiform discharges (IEDs) recorded during overnight sleep-EEG studies in temporal lobe epilepsy. Because IEDs are more prevalent in non-rapid eye movement (NREM) sleep than in wakefulness, overnight sleep-EEG recordings may contribute additional lateralizing information to the epilepsy surgery evaluation beyond daytime EEGs.Methods: Twenty-four subjects with medically refractory temporal lobe epilepsy underwent continuous overnight sleep-EEG recordings. Subjects were seizure free 2 2 4 h before study and receiving stable doses of medication. The IED foci recorded on overnight studies were compared with daytime EEGs, interictal samples, and ictal recordings during long-term monitoring, brain magnetic resonance images (MRIs), and surgical outcome.Results: (a) In all 24 subjects, including 13 without IEDs on daytime EEGs, temporal IEDs were present during NREM sleep and were exclusively or predominantly (>95%) unilateral in 15 and bitemporal in nine. (b) Unilateral NREM IEDs were concordant with surface or depth ictal-onset regions in 14 subjects, even if MRIs were normal (three subjects) or surface ictal-onset regions were bilateral (five subjects). Eleven of 12 subjects with unilateral concordant NREM IEDs who have undergone surgery are seizure free. (c) Bitemporal IEDs were associated with postoperative seizures in a11 subjects with normal MRIs or widespread MRI abnormalities. However, all subjects with bitemporal IEDs and MRI hippocampal abnormalities concordant with ictal-onset regions had good to excellent surgical outcomes.Conclusions: When combined with other investigations, IEDs recorded on overnight studies add prognostic data to the epilepsy surgery evaluation not provided by daytime EEGs.Key Words: Sleep-Epilepsy-ElectroencephalographyInterictal epileptiform discharges-Surgery.The activating effect of sleep on electroencephalographic (EEG) activity in epilepsy has been established for >50 years (1). Non-rapid eye movement (NREM) sleep increases interictal epileptiform discharges (IEDs) in partial epilepsy (2,3). In contrast, IEDs are relatively suppressed during rapid eye movement (REM) sleep. The activating role of NREM sleep on epileptic cortex has been attributed to increased neuronal synchronization within thalamocortical projection neurons, resulting from the neurochemical and neurophysiologic processes that initiate and maintain NREM sleep (4).Although the usefulness of sleep-EEG recordings for the diagnosis of epilepsy is well established (5) ( 3 ) found that IEDs were more frequent in delta NREM sleep and that NREM sleep extended and REM sleep restricted the IED field in subjects with temporal lobe epilepsy. By using log delta power to measure sleep depth in subjects with partial epilepsy Malow and co-workers (6) showed that the rate of IEDs increased in delta sleep and in deepening NREM sleep. Overnight continuous sleep-EEG studies, therefore, may provide useful information about IED foci that are not provided by daytime E...

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“…Long-term waking and sleep scalp EEG [1] was used to assess the lateralization of interictal epileptiform discharges and/or interictal focal slowing in the theta and delta range [7]. Two or more complexpartial seizures were recorded from all patients using video-EEG.…”

Section: ■ Subjectsmentioning

confidence: 99%

Hippocampal atrophy in temporal lobe epilepsy is correlated with limbic systems atrophy

et al. 2005

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Hippocampal sclerosis in temporal lobe epilepsy (TLE) is often associated with hippocampal atrophy. This study assessed whether such atrophy is correlated with loss of gray matter volume in other brain regions. In 16 patients with TLE and clear magnetic resonance imaging-based evidence of hippocampal sclerosis, hippocampal volumes were determined manually and the local gray matter (LGM) amount was estimated throughout the entire brain using voxel-based morphometry. Voxelwise correlations between the volume of the sclerotic hippocampus and LGM were computed. The pattern of voxels whose LGM correlated with hippocampal volume outlined remarkably well the anatomy of the extended limbic system and included the parahippocampal region, cingulate gyrus throughout its extent, basal forebrain, thalamic nuclei, medial orbitofrontal areas and the insula. These correlations emerged mainly on the side ipsilateral to the affected hippocampus but were also found contralaterally. No such correlations were found in a group of 16 healthy controls. The present data show that hippocampal volume loss in TLE is associated with a widespread limbic systems atrophy. These findings are helpful to better understand the functional deficit and reorganization often found in temporal lobe epilepsy and will also provide a basis to assess neural plasticity in the limbic system for those patients who will undergo curative temporal lobe surgery.

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Predictive Value of Interictal Epileptiform Discharges During Non‐REM Sleep on Scalp EEG Recordings for the Lateralization of Epileptogenesis

Cited by 68 publications

References 24 publications

Interictal Spiking Increases with Sleep Depth in Temporal Lobe Epilepsy

Interictal Spiking Increases with Sleep Depth in Temporal Lobe Epilepsy

Lateralizing Value of Interictal Spikes on Overnight Sleep‐EEG Studies in Temporal Lobe Epilepsy

Hippocampal atrophy in temporal lobe epilepsy is correlated with limbic systems atrophy

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