Sleep-Wake Patterns of Seizures in Children With Lesional Epilepsy

This study examined diurnal patterns of seizures and their occurrence during wakefulness and sleep in children with lesional focal epilepsy. We reviewed 332 consecutive children with lesional focal epilepsy and video-electroencephalogram monitoring during a 3-year period. Data were analyzed in relationship to clock time, wakefulness/sleep, and seizure localization. The distribution of lesions in 66 children (259 seizures) included mesial temporal, 29%; neocortical temporal, 18%; frontal, 29%; parietal, 13.5%; and occipital, 12%. Seizures in patients with frontal lesions occurred mostly during sleep (72%). Seizures in mesial temporal (64%), neocortical temporal (71%), and occipital (66%) lesional epilepsy occurred mostly during wakefulness. Temporal lobe seizures occurred more frequently during wakefulness (66%), compared with extratemporal seizures (32%) (odds ratio, 2.67; 95% confidence interval, 1.61-4.42). Temporal lobe seizures peaked between 9:00 am and noon and 3:00-6:00 pm, whereas extratemporal seizures peaked between 6:00-9:00 am. Sleep, not clock time, provides a more robust stimulus for seizure onset, especially for frontal lobe seizures. Temporal lobe seizures are more frequent during wakefulness than are extratemporal seizures. Circadian patterns of seizures may provide additional diagnostic and treatment options, such as differential medication dosing and sleep-schedule adjustments.     

24-hour rhythmicity of seizures in refractory focal epilepsy

The occurrence of seizures in specific types of epilepsies can follow a 24-hour nonuniform or nonrandom pattern. We described the 24-hour pattern of clinical seizures in patients with focal refractory epilepsy who underwent video-electroencephalography monitoring. Only patients who were candidates for epilepsy surgery with an unequivocal seizure focus were included in the study. A total of 544 seizures from 123 consecutive patients were analyzed. Specific time of seizures were distributed along 3- or 4-hour time blocks or bins throughout the 24-hour period. The mean age of the subjects was 37.7 years, with standard deviation of 11.5 years, median of 37. The majority were females (70/56%). The majority of patients had a seizure focus located in the mesial temporal lobe (102/83%) and in the neocortical temporal lobe (13/11%). The remaining patients had a seizure focus located in the extratemporal lobe (8/6%). The most common etiology was mesial temporal sclerosis (86/69.9%). Nonuniform seizure distribution was observed in seizures arising from the temporal lobe (mesial temporal lobe and neocortical temporal lobe), with two peaks found in both 3- and 4-hour bins: 10:00–13:00/16:00–19:00 and 08:00–12:00/16:00–20:00 respectively (p = 0.004). No specific 24-hour pattern was identified in seizures from extratemporal location. The 24-hour rhythmicity of seizure distribution is recognized in certain types of epilepsy, but studies on the topic are scarce. Their replication and validation is therefore needed. Our study confirms the bimodal pattern of temporal lobe epilepsy independently of the nature of the lesion. However, peak times differ between different studies, suggesting that the ambient, rhythmic exogenous factors or environmental/social zeitgebers, may modulate the 24-hour rhythmicity of seizures. Characterization of these 24-hour patterns of seizure occurrence can influence diagnosis and treatment in selected types of epilepsy, such as the case of temporal lobe epilepsy, the most common drug-resistant epilepsy.     

Prevalence and predictors of subclinical seizures during scalp video-EEG monitoring in patients with epilepsy

Objective: This study first aimed to establish the prevalence and predictors of subclinical seizures in patients with epilepsy undergoing video electroencephalographic monitoring, then to evaluate the relationship of sleep/wake and circadian pattern with subclinical seizures. Methods: We retrospectively reviewed the charts of 742 consecutive patients admitted to our epilepsy center between July 2012 and October 2014. Demographic, electro-clinical data and neuroimage were collected. Results: A total of 148 subclinical seizures were detected in 39 patients (5.3%) during video electroencephalographic monitoring. The mean duration of subclinical seizures was 47.18 s (range, 5–311). Pharmacoresistant epilepsy, abnormal MRI and the presence of interictal epileptiform discharges were independently associated with subclinical seizures in multivariate logistic regression analysis. Subclinical seizures helped localizing the presumed epileptogenic zone in 24 (61.5%) patients, and suggested multifocal epilepsy in five (12.8%). In addition, subclinical seizures occurred more frequently in sleep and night than wakefulness and daytime, respectively, and they were more likely seen between 21:00–03:00 h, and less likely seen between 09:00–12:00 h. Thirty patients (76.9%) had their first subclinical seizures within the first 24 h of monitoring while only 7.7% of patients had their first subclinical seizures detected within 20 min. Conclusion: Subclinical seizures are not uncommon in patients with epilepsy, particularly in those with pharmacoresistant epilepsy, abnormal MRI or interictal epileptiform discharges. Subclinical seizures occur in specific circadian patterns and in specific sleep/wake distributions. A 20-min VEEG monitoring might not be long enough to allow for their detection.     

Temporal relationship between awakening and seizure onset in nocturnal partial seizures

Clinical awakening can be seen just before or after seizure onsets. In this study we determined the time between onset of seizures and awakening in patients with frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE). Sixty-eight patients who underwent video-EEG monitoring with simultaneous PSG were retrospectively examined. TLE or FLE patients having seizures during sleep were included. Seizure onset and awakening onset were marked according to clinical and electrophysiological features. The duration between awakening and seizure onset was compared in patients with TLE and FLE. Twenty-five patients who had been diagnosed with TLE (17) or FLE (8) had a total of 75 seizures during sleep. All seizures except one, occurred during NREM sleep in both TLE and FLE patients. The seizure onsets were before awakening in 49 seizures (FLE: 20, TLE: 29) and the awakening preceded the seizure onsets in 12 seizures (FLE: 3, TLE: 9). The duration between seizure onset and the awakening was shorter in FLE, either in seizures with preceding awakening or not (p=0.014, p=0.015). Awakening was mostly seen after onset of seizures rather than before, especially in TLE. But in patients with FLE the duration between seizure onset and awakening was shorter. The localization of epileptic activity may play a role for the timing of awakening mechanisms during nocturnal partial seizures.     

Lateralizing value of behavioral arrest in patients with temporal lobe epilepsy

Analysis of ictal semiology is essential to presurgical evaluation of patients with epilepsy. To assess the localizing value of behavioral arrest in temporal lobe epilepsy (TLE), we analyzed 107 video/EEG monitoring-documented seizures of 107 adult patients with TLE for a set of defined seizure phenomena with respect to frequency and sequence of occurrence in relation to epileptogenic (mesial vs extramesial, left vs right) origin. Behavioral arrest was observed more frequently in left-sided temporal seizures: 25.7% of left-sided mesial seizures and 25.0% of left-sided extramesial seizures exhibited behavioral arrest, whereas only 3.4% of right-sided mesial seizures and 10.5% of right-sided extramesial seizures were associated with behavioral arrest. In addition, occurence of behavioral arrest within the sequence of seizure phenomena was remarkably consistent, being observed mainly as the first apparent feature of seizure onset. Thus, behavioral arrest is a valuable early indicator of a left-sided temporal epileptogenic focus in adult patients with TLE.     

Spatial extent of neuronal metabolic dysfunction measured by proton MR spectroscopic imaging in patients with localization-related epilepsy

SUMMARY: PURPOSE: To assess the spatial extent of the decrease in the neuronal marker N-acetyl-aspartate (NAA) relative to creatine (Cr) in patients with localization-related epilepsy, and to assess clinical differences between patients with and without widespread NAA/Cr reduction. METHODS: We studied 51 patients with localization-related epilepsy. Patients were divided into three groups according to the EEG investigation: (a) temporal lobe epilepsy (TLE, n = 21), (b) extratemporal lobe epilepsy (extra-TLE, n = 20), and (c) multilobar epilepsy (patients with a wider epileptogenic zone, n = 10). We acquired proton magnetic resonance (MR) spectrocopic imaging (1H-MRSI) of temporal and frontocentroparietal regions in separate examinations for both patients and controls. NAA/Cr values 2 standard deviations below the mean of normal controls were considered abnormal. RESULTS: Twenty-three (45%) patients including 12 with TLE had normal MR imaging including volumetric studies of the hippocampus. Forty-nine (96%) patients had low NAA/Cr, indicating neuronal dysfunction in either temporal and/or extratemporal 1H-MRSIs; 38% of patients with TLE and 50% of patients with extra-TLE also had NAA/Cr reduction outside the clinical and EEG-defined primary epileptogenic area. The NAA/Cr reduction was more often widespread in the multilobar group [six (60%) of 10] than in temporal or extratemporal groups [five (31%) of 16]. Nonparametric tests of (a) seizure duration, (b) seizure frequency, and (c) lifetime estimated seizures showed no statistically significant difference (p > 0.05) for TLE and extra-TLE patients with or without NAA/Cr reduction outside the seizure focus. CONCLUSIONS: Of patients with localization-related epilepsy, 40-50% have neuronal metabolic dysfunction that extends beyond the epileptogenic zone defined by clinical-EEG and/or the structural abnormality defined by MRI.     

Temporal distribution of clinical seizures over the 24‐h day: A retrospective observational study in a tertiary epilepsy clinic

Purpose: Very few studies have evaluated seizure occurrence in humans over the 24‐h day; data from children are particularly scarce. Circadian patterns in seizure occurrence may be of importance in epilepsy research and may have important implications in diagnosis and therapy. Methods: We have analyzed clinical seizures of 176 consecutive patients (76 children, 100 adults) who had continuous electroencephalography (EEG) and video monitoring lasting more than 22 h. Several aspects of seizures were noted, including classification, time of day, origin, and sleep stage. Results: More than 800 seizures were recorded. Significantly more seizures were observed from 11:00 to 17:00 h, and from 23:00 to 05:00 h significantly fewer seizures were seen. The daytime peak incidences were observed in seizures overall, complex partial seizures (in children and adults), seizures of extratemporal origin (in children), and seizures of temporal origin (in adults). Incidences significantly lower than expected were seen in the period 23:00 to 05:00 h in seizures overall, complex partial seizures (in children and adults), and in tonic seizures (in children). In addition, significantly fewer seizures of temporal (in children and adults) and extratemporal origin (in children) were observed in this period. Discussion: The results suggest that certain types of seizures have a strong tendency to occur in true diurnal patterns. These patterns are characterized by a peak during midday and a low in the early night.     

The Relationship Between Sleep and Epilepsy in Frontal and Temporal Lobe Epilepsies: Practical and Physiopathologic Considerations

Summary: Purpose: The influence of sleep on the incidence of seizures and the reciprocal effects of epilepsy on sleep were analyzed in 30 patients with intractable partial seizures, all candidates for surgery.
Methods: The patients were classified into two groups of 15 patients according to the documented site of the epileptogenic zone: frontal lobe epilepsy (FLE) and medial temporal lobe epilepsy (TLE). Frequency and waking-sleep distribution of seizures were evaluated by continuous video-EEG monitoring for 5 days, under defined antiepileptic drug (AED), sleep, and sleep deprivation regimens. Sleep organization was analyzed by polysomnography prior to the presurgical protocol.
Results: Significant differences were found between the two groups in sleeping-waking distribution of seizures under varied conditions, and in the quality of sleep organization. In FLE patients, seizures most often occurred during sleep, although sleep organization was normal. In TLE patients, most seizures occurred while patients were awake, and sleep organization was characterized by a low efficiency index. The difference in seizure distribution between FLE and TLE persisted under all conditions investigated, i.e., after AED discontinuation and sleep deprivation.
Conclusions: Sleep recording may be useful for diagnosis of FLE, and monitoring after sleep deprivation for that of TLE. We speculate that sleep-related seizures in FLE may depend on interaction between frontal lobe areas with the thalamus cortical synchronization system and the acetylcholine regulatory system of waking.     

Factors affecting spiking related to sleep and wake states in temporal lobe epilepsy (TLE).

The aim of the study was to investigate the influence of different clinical factors on spiking during sleep and wakefulness in temporal lobe epilepsy. The study included 38 temporal lobe epilepsy (TLE) patients who underwent long-term electroencephalography (EEG) monitoring. In addition to traditional sleep scoring, waking was subdivided into eyes opened (WEO) and eyes closed (WEC) states. The following spike measures were investigated: spiking rates for each state, mean spike rate, spiking stability across wake and sleep states and relative spike density for each state. These measures were investigated according to clinical variables, such as age, age at epilepsy onset, duration of epilepsy, seizure frequency, the presence of secondarily generalised tonic-clonic (SGTC) seizures and the data on epileptogenic lesions based on MRI. Spiking rates during most states and spiking stability showed a significant positive correlation with epilepsy duration. Relative spike density during sleep stage NREM3,4 significantly increased with age at epilepsy onset. Relative spike density during WEC was significantly higher in the presence of hippocampal sclerosis (HS). Spiking rate during REM was significantly higher if a patient had SGTC seizures. Our data provide evidence that different aspects of spiking are associated with different aspects of TLE. We suggest that spike behaviour analysis offer new aspects both for diagnosis and research.     

The localizing value of the abdominal aura and its evolution: a study in focal epilepsies.

OBJECTIVE: To evaluate the localizing value of abdominal aura and its evolution into other seizure types. METHODS: The seizures of 491 consecutive patients with focal epilepsies were prospectively classified according to a recently introduced semiologic seizure classification. All patients underwent prolonged EEG video monitoring and MRI scan. Two hundred twenty-three patients (45%) had temporal lobe epilepsies (TLE); 113 patients (23%) had extratemporal epilepsies; and for 155 (32%) patients, the epilepsy could not be localized to one lobe. RESULTS: Abdominal auras were more frequent with TLE (117 of 223 patients, 52%) than in extratemporal epilepsy (13 of 113 patients, 12%, p < 0.0001) and more frequent in mesial TLE (70 of 110 patients, 64%) than in neocortical TLE (16 of 41 patients, 39%, p = 0.007). No preponderance to one side existed. Abdominal auras were followed by ictal oral and manual automatisms (automotor seizure) in at least one seizure evolution in all patients with TLE (117 patients, 100%). In contrast, only two patients with extratemporal epilepsy (2 of 13 patients, 15%, p < 0.0001) had abdominal auras evolving into automotor seizures. An abdominal aura is associated with TLE with a probability of 73.6%. The evolution of an abdominal aura into an automotor seizure, however, increases the probability of TLE to 98.3%. CONCLUSIONS: These results demonstrate that evolution of abdominal aura into automotor seizure permits differentiation between temporal lobe epilepsy and extratemporal epilepsy, showing that analysis of seizure evolution provides more localizing information than does the frequency of particular seizure types.     

Depth Electrode Studies in Temporal Lobe Epilepsy: Relation to Quantitative Magnetic Resonance Imaging and Operative Outcome

Summary: We performed a retrospective study of 30 patients with presumed intractable temporal lobe epilepsy (TLE) who underwent chronic intracranial EEG monitoring (CIEM). Multicontact depth electrodes were stereotactically implanted through the medial occipital lobe into amygdala and hippocampus. All patients had previously undergone extracranial ictal EEG monitoring that proved inadequate to localize the epileptogenic zone. No morbidity as associated with CIEM in the 30 patients. Twenty-five patients were shown to have exclusively or predominantly unilateral temporal lobe seizures, and 5 patients had bitemporal seizures without unilateral predominance; 24 patients subsequently underwent an anterotemporal lobe cortical resection. Twenty-one patients have been followed a minimum of 1 year postoperatively. Nine patients (43%) had a class I outcome (seizure-free, auras only, or provoked seizures), 3 patients (14%) had a class I1 outcome (≥95% seizure reduction), 4 patients (19%) had a class III outcome (≥50% seizure reduction); and 5 patients (24%) had a class IV outcome (<50% seizure reduction or no change). A prolonged interhemispheric propagation time (p <0.01) and magnetic resonance imaging (MR1)-identified hippocampal atrophy (p <0.01) correlated with a favorable surgical outcome. Results of this study may prove useful in counseling patients who undergo CIEM before temporal lobe surgery.     

Temporal distribution of partial seizures: Comparison of an animal model with human partial epilepsy

Seizures do not often strike randomly but may occur in circadian patterns. We compared daily times of partial seizures determined by continuous electroencephalography among patients with mesial temporal lobe epilepsy (MTLE; n = 64), those with extratemporal lobe (XTLE; n = 26) or lesional temporal lobe epilepsy (LTLE; n = 8), and a rat model similar to MTLE in which rats become epileptic after electrically induced limbic status epilepticus (postlimbic status [PLS]; n = 20). Rats were maintained on a 12-hour light/dark cycle with lights on at 0700 hours. The distributions of seizures were fitted by cosinor analysis to determine time of peak seizure incidence ± 95% confidence interval (95% CI). The mean fraction ± SD of seizures recorded during light was 63 ± 17% in PLS animals and 60 ± 21% in humans. Peak incidence of seizures for PLS rats (547 seizures) was 1645 (95% CI = 1448,1830) and for MTLE subjects (774 seizures) was 1500 (95% CI = 1324,1636). Seizures from XTLE (465 seizures) and LTLE (48 seizures) did not fit a cosinor model and occurred no more frequently during light than dark. In conclusion, limbic seizures in humans and PLS rats occur more often during light than dark and have similar cosinor daily distributions. The chronological similarity between human MTLE and PLS rat epilepsy suggests that limbic seizure occurrence has a relation to the circadian regulatory system.     

Clinical factors associated with post-ictal headache in patients with epilepsy

OBJECTIVES: To determine the incidence of post-ictal headaches (PIH) and clinical risk factors associated with the occurrence of PIH in patients with localization-related epilepsy. MATERIALS AND METHODS: The subjects were 77 patients with temporal lobe epilepsy (TLE), 34 patients with occipital lobe epilepsy (OLE), and 50 patients with frontal lobe epilepsy (FLE). The subjects were directly asked whether headaches occurred just after seizures. Medical charts were reviewed to ascertain the clinical characteristics of epilepsy in these patients. RESULTS: The incidence of PIH was 23% for TLE, 62% for OLE, and 42%, for FLE. The risk of PIH was significantly higher for OLE than for TLE or FLE, and for patients with generalized tonic-clonic seizures. Younger age at onset of epilepsy was also a risk factor for PIH. CONCLUSION: The occurrence of PIH may be related to the region of epileptic focus and the region of spread of epileptic discharges.     

Electrophysiologic Analysis of a Chronic Seizure Model After Unilateral Hippocampal KA Injection

PURPOSE: Unilateral intrahippocampal injections of kainic acid (KA) in rats produce spontaneous recurrent limbic seizures and morphologic changes in hippocampus that resemble hippocampal sclerosis in patients with medically refractory mesial temporal lobe epilepsy (MTLE), that form of temporal lobe epilepsy (TLE) associated with hippocampal sclerosis. Interictal in vivo electrophysiologic studies have revealed high-frequency (250-500 Hz) oscillations, termed fast ripples (FRs). These oscillations may uniquely occur in or adjacent to the site of hippocampal KA injection, in areas that generate spontaneous seizures. Similar field potentials also have been demonstrated in the epileptogenic region of patients with TLE. We have now characterized ictal electrographic patterns in this rat model for comparison with those in human TLE and begun to evaluate the role of FRs in the transition to ictus in the KA-treated rat. METHODS: Rats received unilateral intrahippocampal injections of KA and, after the development of spontaneous seizures, were implanted with multiple fixed and moveable microelectrodes for single unit, field potential, and EEG recording. They were then monitored by using video-EEG telemetry for several weeks to capture and evaluate electrographic and behavioral seizure types. Results were correlated with Timm's stain demonstration of mossy fiber sprouting. RESULTS: Low-voltage fast (LVF) and hypersynchronous electrographic ictal-onset patterns were seen in the KA-treated rat that resembled similar ictal-onset patterns in patients with TLE. Hypersynchronous, but not LVF, ictal discharges were associated with recurrent FRs. As in the human, hypersynchronous ictal onsets originated predominantly in hippocampus, whereas LVF ictal onsets more often involved extrahippocampal structures. LVF ictal onsets occurred during wakefulness or paradoxical sleep and were usually associated with motor behavior, whereas hypersynchronous ictal onsets occurred during slow-wave sleep or periods of immobility and were not associated with motor behavior unless there was transition to another ictal electrographic pattern. Mossy fiber sprouting did not correlate with the frequency of ictal EEG discharges exhibited by each rat but was greater in those rats that demonstrated frequent behavioral seizures. CONCLUSIONS: The electrographic features of spontaneous seizures in the KA-treated rat resemble those of patients with medically refractory TLE with respect to EEG pattern and localization. Our data suggest that hypersynchronous ictal onsets represent epileptogenic disturbances in hippocampal circuits, whereas LVF ictal onsets may involve extrahippocampal areas having more direct connections to the motor system. Hypersynchronous seizures may involve the same neuronal mechanisms that generate interictal FRs.     

Surgical implications of neuromagnetic spike localization in temporal lobe epilepsy

PURPOSE: To investigate the clinical usefulness of magnetoencephalography (MEG) as a guide to the surgical treatment of temporal lobe epilepsy (TLE). METHODS: Preoperative spike localization by MEG was compared with seizure outcome and postoperative spike localization at 12 months after resective surgery in 16 patients with TLE. Spike localization was classified into anterior temporal (AT) and non-AT localization in 11 patients without neocortical lesion treated with anterior temporal lobectomy (ATL); and lesion and lobar localization in five patients with neocortical lesion treated with lesionectomy (n = 3) or lesionectomy with medial temporal resection (n = 2). RESULTS: All five patients with AT localization became seizure free and spike free after surgery. Among the six patients with non-AT localization, two became seizure free and spike free, two became seizure free with residual spikes, one had residual seizures but no spikes, and one had both residual seizures and spikes. All three patients with lesion localization and two with lobar localization had favorable seizure outcome and became spike free after surgery. CONCLUSIONS: MEG spike localization can identify neocortical sources remote from the presumed epileptogenic area. Favorable seizure outcome can be expected in patients with AT localization after ATL and patients with lesion localization after lesionectomy. In contrast, non-AT localization indicates either nonmedial TLE or spike propagation to the posterior and extratemporal neocortex. Similarly, lobar localization indicates spike propagation from an epileptogenic lesion or extensive epileptogenicity. Patients with non-AT localization or lobar localization should undergo intensive evaluations, such as intracranial EEG, for improved seizure outcome.     

Predicting diurnal and sleep/wake seizure patterns in paediatric patients of different ages

Aim. To identify factors that influence diurnal and sleep/wake seizure timing in children undergoing tapered drug withdrawal in an epilepsy monitoring unit. Methods. Medical charts of patients that underwent video‐EEG were reviewed. Seizures were evaluated based on their occurrence in three‐hour time intervals (bins) and between wakefulness and sleep. Patients were classified according to EEG localisation and age: infants (≤3 years), children (3–12 years), and adolescents (>12–21 years). Analysis utilising generalised estimating equations with a negative binomial distribution was performed. Results. A total of 390 patients (188 girls; mean age: 9.2 years; SD: 6.0) had 1,754 seizures. Generalised seizures (109 patients; 490 seizures) occurred more during wakefulness (p<0.001) and during the day (p<0.001). Modelling revealed a greater occurrence of seizures at night with increasing age (p=0.046). Temporal lobe seizures (62 patients; 271 seizures) occurred overall more frequently during wakefulness (p=0.03). Frontal lobe seizures (41 patients; 184 seizures) occurred more frequently during wakefulness in infants (p<0.05) and more frequently during sleep in adolescents (p<0.0001). Adolescents with frontal lobe seizures were 3.6 times more likely to have seizures during sleep compared to other children (95% CI: 1.8–7.2). Conclusion. These findings are suggestive of changes in circadian rhythmicity that may alter seizure susceptibility in different age groups. The results may assist in prediction of periods of greatest seizure propensity.     

Reduction of rapid eye movement sleep by diurnal and nocturnal seizures in temporal lobe epilepsy

BACKGROUND: Patients with brief, complex partial seizures frequently suffer from tiredness and decreased productivity that continue well beyond the postictal period. A possible explanation is that seizures, even when occurring during the day, disrupt sleep the following night. OBJECTIVE: To determine the effect of temporal lobe complex partial seizures on sleep structure and daytime drowsiness. METHODS: Patients with temporal lobe epilepsy were admitted for video-electroencephalography monitoring. All-night polysomnography was recorded under the following 3 conditions: seizure free, seizure during the day before the recording, and seizure during the recording. Percentage of time in each sleep stage, sleep efficiency, and time to first and second rapid eye movement (REM) period were compared for seizure vs control conditions. Daytime drowsiness was also measured, using a modified maintenance of wakefulness test and 2 subjective drowsiness tests. RESULTS: Daytime seizures reduced REM from 18%+/-1% to 12%+/-2% (P = .003). Night seizures reduced REM from 16%+/-1% to 6.8%+/-2% (P<.001). Night seizures also significantly reduced stages 2 and 4 while increasing stage 1 sleep. Night seizures, but not day seizures, significantly reduced sleep efficiency, increased time to first REM period, and increased drowsiness as measured by the maintenance of wakefulness test. CONCLUSIONS: Temporal lobe complex partial seizures decrease REM sleep, particularly when occurring during sleep but also when occurring on the previous day. This may, in part, be responsible for the prolonged impairment of functioning that some patients report following seizures.     

Seizures by the clock: Temporal patterns of psychogenic nonepileptic seizures

We hypothesized that (1) the occurrence of psychogenic nonepileptic seizures (PNES) is modulated by the interaction between the 24-hour clock and the sleep–wake cycle and (2) the pattern of modulation in PNES differs from epileptic seizures (ES). We sought to test our hypotheses in a cohort of patients diagnosed with PNES or ES in the setting of an epilepsy monitoring unit (EMU). We retrospectively reviewed consecutive video-EEG (VEEG) recordings of patients who underwent monitoring at the EMU of a tertiary hospital. The seizure type (PNES vs ES), onset time, and the state (sleep vs awake) were tabulated. The relationship between the onset time, the state of arousal, and the occurrence of PNES was determined using logistic regression analysis. To determine if the nature of the relationship between the state of arousal and PNES differed according to the onset time, an interaction between the onset time and the state of arousal was also fitted to the model. We studied a total of 754 seizures (ES, 437; PNES, 317) from 135 patients consisting of 71 (52.6%) females and 64 (47.4%) males with the median age of 39 years (range, 18–91). We found a significant association between the state of arousal and PNES with the odds of being PNES four times higher when patients were awake (OR: 4.27, 95% CI: 2.44–7.48; p < 0.0001) compared with when they were asleep. The analysis further revealed a significant interaction between the onset time and the state of arousal (p = 0.004). The odds of being PNES were significantly higher if the seizure occurred when the patient was awake at night. These patterns possibly indicate the complex interaction between the sleep–wake cycle and the 24-hour time cycle in the generation of PNES.     

Emotional facial paresis in temporal lobe epilepsy: its prevalence and lateralizing value.

The selection of patients with medically refractory temporal lobe epilepsy (TLE) for surgery depends on the concordance of data from clinical, imaging and electroencephalographic evaluation. Though clinical examination is often normal, emotional facial paresis has been described in patients with TLE. Utilizing a well-characterized group of mesial TLE (MTLE) patients, who have achieved excellent seizure outcome following anterior temporal lobectomy with amygdalohippocampectomy (ATL), we investigated the prevalence, predictive value and associations of emotional facial paresis. When compared to 8 out of 50 control subjects (16%), 36 out of 50 MTLE patients (72%) exhibited unilateral emotional facial paresis; the difference was highly significant (P<0.0001). The presence of contralateral emotional facial paresis correctly predicted the side of ATL in 86.1% patients. The occurrence of emotional facial paresis was significantly associated with longer duration of epilepsy prior to ATL and left ATL. Our observations confirm that emotional facial parersis contralateral to the side of mesial temporal sclerosis (MTS) is a valuable localizing sign in correctly predicting the epileptogenic temporal lobe. We hypothesize that the presence of an intact right hemisphere and pathological changes more extensive than MTS may be required for emotional facial paresis to readily manifest.     

The epileptogenic zone in pharmaco‐resistant temporal lobe epilepsy with amygdala enlargement

Aims. Temporal lobe epilepsy with amygdala enlargement (TLE‐AE) has been considered a subtype of TLE. We evaluated the epileptogenic zone in patients with TLE‐AE, who underwent intracranial video‐EEG (ivEEG) and/or intraoperative electrocorticography (ioECoG) as well as epilepsy surgery. Methods. Eleven patients with TLE‐AE were enrolled and investigated based on seizure profile, volumetric MRI, the Wechsler Memory Scale‐Revised (WMS‐R), the location of seizure onset zone (SOZ) and irritative zone (IZ) based on ivEEG (n=8), the location of interictal epileptiform discharges (IEDs) based on ioECoG (11), surgical procedure, and seizure outcome. Results. The mean age at seizure onset was 34.9 years (range: 23–57). The mean duration of seizures was 5.0 years (range: 1–10). The number of AEDs was 2.3 (range: 1–5). The mean seizure frequency was nine per month (range: 1–30/month). All patients presented with focal impaired awareness seizures with (n=9) and without (2) secondary generalized convulsions. Volumetric MRI analysis showed unilateral enlarged amygdala with statistical significance (p<0.01). None of the patients' hippocampi had any abnormality based on MRI. Pre‐operative mean verbal, visual, and delayed recall scores based on the WMS‐R were over 100. The SOZ and IZ were identified in both the amygdala and hippocampus in seven patients and in only the amygdala in one patient based on ivEEG. IEDs were identified in the hippocampus in six patients and in both the amygdala and hippocampus in four patients based on ioECoG. All 11 patients underwent anterior temporal lobectomy, including amygdala resection, with multiple hippocampal transections (dominant hemisphere: seven patients) and resection (non‐dominant hemisphere: three patients). Nine (81.8%) of 11 patients achieved seizure freedom with a mean follow‐up of 26 months (range: 12–47). Post‐operative WMS‐R results did not show any significant deterioration, with a mean follow‐up of 15 months (range: 12–24). The resected amygdala showed no histopathological abnormality. Conclusion. The epileptogenic zone of TLE‐AE involves both the amygdala and hippocampus. ivEEG may be needed to explore the SOZ in normal hippocampus in addition to enlarged amygdala. Amygdala resection and multiple hippocampal transections may control the epileptogenic limbic system and save memory function in patients with TLE‐AE.