Sleep instability and cognitive status in drug-resistant epilepsies

ObjectiveThe aims of this study were to evaluate the sleep habits of children with drug resistant epilepsy and to correlate sleep abnormalities with epilepsy and level of intelligence.Subjects and methodsTwenty five subjects with drug resistant epilepsy (14 males, age range 2–16.4 years) were recruited for this study. A control group was formed by 23 normal children. Two instruments to assess sleep habits were administered to the patients with epilepsy: a questionnaire on sleep habits (to preschool children) and a questionnaire on sleep behavior (for children aged more than seven years old); a cognitive test (Wechsler Intelligence Scale for Children-WISC) was also performed. Patients underwent a complete polysomnographic study and sleep parameters, including CAP, were analyzed and correlated according to cognitive-behavioral measures in children with epilepsy.ResultsChildren with drug-resistant epilepsy and severe mental retardation showed sleep abnormalities such as low sleep efficiency, high percentage of wakefulness after sleep onset, reduced slow wave sleep, and reduced REM sleep. Sleep microstructure evaluated by means of CAP analysis showed a decrease in A1 index during N3 in patients with more severe cognitive impairment. Children with epilepsy and cognitive impairment (n = 10) had higher Sleep Behavior Questionnaire for Children (SBQC) total scores (65.60 ± 18.56) compared to children with epilepsy and normal IQ (50.00 ± 10.40), p < 0.05.ConclusionsChildren with drug-resistant epilepsy have a greater incidence of sleep problems regarding qualitative aspects, macrostructure, and CAP. The decrease of CAP rate and of A1, mainly during slow wave sleep (associated to REM sleep reduction), might represent a sleep microstructural pattern of intellectual disability.     

Severity of anxiety and depression are related to a higher perception of adverse effects of antiepileptic drugs

After reviewing the negative effects of antiepileptic drugs (AEDs) on general health and quality of life, the Commission on Outcome Measurement from the International League Against Epilepsy (ILAE) recommended incorporating reliable and valid tools in clinical essays in order to achieve a more accurate assessment of the subjective adverse effects rate and disease severity when using AEDs.PurposeThe aim of this study was to correlate the severity of adverse effects of AEDs, with the presence of anxiety and depression in patients with epilepsy.MethodsThe Spanish version of the Liverpool Adverse Events Profile (LAEP) and the Hospital Anxiety and Depression Scale (HADS) were applied on 130 consecutive outpatients with epilepsy from the epilepsy clinic at the Mexico's National Institute of Neurology and Neurosurgery. A correlation analysis was carried out to determine if the presence of depression and anxiety was related to the adverse effects of AEDs. The relation between LAEP scores with other epidemiological variables was also assessed.ResultsOur study found a positive correlation between the LAEP and the HADS scores (p = <0.01).The most common adverse effects were drowsiness (81.5% [n = 106]), difficulty in concentrating (76% [n = 99]), and nervousness and/or agitation (75% [n = 97]). Female gender, a history of febrile seizures, persistent seizures and polytherapy were associated with a higher toxicity on LAEP. In our study, age at epilepsy onset, duration of epilepsy, type of epilepsy and patients’ age were not related to higher LAEP scores.ConclusionAdverse effects to AEDs can be related with the presence of psychiatric disorders such as anxiety and depression in patients with epilepsy.     

A reduction of sleep spindles heralds seizures in focal epilepsy

ObjectivesSleep has profound effects on epilepsy. It may alter the occurrence of interictal discharges (IEDs) and seizures. Vice versa, an active epilepsy changes sleep. Sleep spindles are typically associated with an increase of IEDs. We examined whether seizures change the number and power of spindles preceding nightly seizures.MethodsWe retrospectively examined the nightly EEG recordings of presurgical epilepsy patients from our EEG-video-monitoring unit. We evaluated the 200 s before the EEG seizure onset for spindle density (spindles per minute) and spindle power and compared that to the interictal baseline sleep.ResultsThe spindle density and the spindle power decreased significantly before the first seizure. The reduction before secondarily generalized seizures (8.7 ± 2.5; p = 0.001) was more pronounced than before focal seizures (10.5 ± 2.5; p = 0.003) compared to baseline (12.2 ± 2.7). This finding was more pronounced in extratemporal lobe epilepsies than in temporal lobe epilepsies. The reduction of spindle power was also significant and was more pronounced in XTLE. These results were consistent for all other seizures during sleep, the mean spindle density decreased significantly in all focal (10.2 ± 1.9; p = 0.001) and generalized preictal period (8.8 ± 2.4; p = 0.001) compared to the mean interictal period (12.1 ± 2.1). These were also more significant in XTLE than TLE group.ConclusionsOur data demonstrate that the occurrence of seizures and propensity of seizure generalisation in focal epilepsy is modulated by specific characteristics of light sleep such as sleep spindles.SignificanceThis study supports the notion that changes in the epileptic network precede the seizure onset and have an influence on seizure generation and termination.     

Memory consolidation in children with epilepsy: Does sleep matter?

IntroductionChildren with epilepsy have frequent sleep disturbance and challenges in learning and memory. There is little research on the consolidation of memory during sleep in this population. The goal of this pilot study was to determine whether children with epilepsy are able to consolidate memories better after a sleep versus wake period as has been demonstrated in typically developing children.MethodsThis study was a prospective evaluation of children with epilepsy to determine if sleep improved episodic memory (using word lists) as compared with memory following a wake period of similar duration. The study was conducted in patients in the Epilepsy Monitoring Unit at a single academic health science center. In the sleep recall condition, the learning trials were presented in the evening, and delayed recall of the words was tested in the morning. In the wake condition, the learning took place in the morning, and the delayed recall took place later in the day. Subjects wore an actigraph to evaluate sleep/wake patterns. Data regarding the children's epilepsy, antiepileptic medications, and frequency of interictal epileptiform discharges were also documented.ResultsTen children (agd 8–17 years) participated in the study. For the entire sample, recall after sleep was better than recall after awake (p = 0.03), and 7 of the 10 children showed this effect. However, reanalyses removing an outlier showed no difference between the two recall conditions. The mean number of interictal epileptiform discharges was 8.8 during the recall after sleep and 7.8 during the recall after awake. Three children had seizures during the evaluation.ConclusionIn this pilot study, we demonstrated that a small cohort of children with epilepsy, with similar interictal epileptiform discharges during sleep and wake, showed no advantage in memory for a word list after a period of sleep than after a period of being awake. This finding requires further study in a larger cohort. Poor memory consolidation during sleep may contribute to the cognitive deficits in children with epilepsy.     

The relation between abnormal behaviors and REM sleep microstructure in patients with REM sleep behavior disorder

ObjectiveTo investigate the temporal relation between rapid eye movement (REM) sleep microstructure (REMs, EMG activity) and motor events in REM sleep behavior disorder (RBD).MethodsPolysomnographic records of eight patients with RBD were analyzed and compared with those of eight sex- and age-matched controls. We examined sleep microstructure for REM sleep with and without REMs and phasic chin EMG activity and their temporal relation to motor events on video.ResultsAll types of motor events were either more frequent in RBD patients than in controls (P ? 0.007) or present solely in RBD patients. In RBD, major motor events were significantly more frequent during REM sleep with REMs than during REM sleep without REMs (violent, 84.0% vs. 16.0%, P < 0.001; complex/scenic behavior, 78.1% vs. 23.2%, P < 0.001; major jerks, 77.5% vs. 20.3%, P < 0.001), whereas minor motor activity was evenly distributed (54.1% vs. 45.9%, P = 0.889). Controls showed predominantly minor motor activity with rare myoclonic body jerks. The distribution of motor events did not differ between REM sleep with and without REMs (40.9% vs. 59.1%, P = 0.262).ConclusionsIn RBD, major motor activity is closely associated with REM sleep with REMs, whereas minor jerks occur throughout REM sleep. This finding further supports the concept of a dual nature of REM sleep with REMs and REM sleep without REMs and implies a potential gate control mechanism of REM sleep with REMs for the manifestation of elaborate or violent behaviors in RBD.     

Latency to first interictal epileptiform discharge in epilepsy with outpatient ambulatory EEG

ObjectiveThe diagnosis and classification of epilepsy often relies upon the demonstration of interictal epileptiform discharges (IEDs). Routine 20-min EEG recording has low sensitivity, with multiple EEGs increasing sensitivity to a maximum of 77% (Doppelbauer et al., 1993). An alternate strategy is the use of prolonged continuous EEG; however, there are no data on the average latency to first IED with ambulatory monitoring.MethodsIn this retrospective study we reviewed 180 consecutive patients with epilepsy referred to a Specialist Epilepsy Unit who had undergone 96 h outpatient ambulatory EEGs, without medication withdrawal, where IEDs were recorded. Latency to, and factors affecting first IED were analysed.ResultsMedian latency to first IED was 316 min, (interquartile range 70–772 min, n = 180). IEDs were recorded in 44% of patients within 4 h, 58% within 8 h, 85% within 24 h and 95% within 48 h. Recording for the full 96 h period revealed only 5% further IEDs. Multivariate analysis showed the latencies to IEDs with generalised epilepsies were shorter than with focal epilepsies (p < 0.0001).ConclusionsIn 95% of patients showing scalp IEDs a 48 h recording was sufficient for electro-clinical classification in this study.SignificanceOur data are the first to show the latency to recording interictal epileptiform discharges with prolonged outpatient EEG monitoring. These data are important in guiding diagnostic practice in Specialist Epilepsy Services.     

Seizure outcome after AED failure in pediatric focal epilepsy: Impact of underlying etiology

ObjectiveThis study aimed to identify long-term seizure outcome in pediatric nonsyndromic focal epilepsy after failure of serial antiepileptic drugs (AEDs) due to lack of efficacy.MethodsChildren (1 month–17 years) with new-onset focal epilepsy not meeting the criteria for a defined electroclinical syndrome diagnosed between 1980 and 2009 while residing in Olmsted County, MN, were retrospectively identified. Medical records of those followed for ≥ 2 years were reviewed to assess etiology, the number of AEDs that failed due to lack of efficacy, and seizure outcome at final follow-up. Etiology was classified into structural/metabolic, genetic, or unknown. Favorable outcome was defined as seizure freedom ≥ 1 year, on or off AEDs, without prior epilepsy surgery. Poor outcome was defined as ongoing seizures in the preceding year or having undergone prior epilepsy surgery.ResultsNonsyndromic focal epilepsy accounted for 275/468 (59%) of all patients with newly diagnosed epilepsy — of these, 256 (93%) were followed for a minimum of two years and were included in the study. Median duration of follow-up was 10.0 years. At least one AED had failed due to lack of efficacy in 100 (39.1%) children. Favorable outcomes occurred in 149/156 (95.5%) children with no AED failure, 16/30 (53.3%) with one AED failure, 8/25 (32%) with two AED failures, and only 2/45 (4.4%) with three AED failures. After two AED failures, the seizures of nearly one-quarter of children who had epilepsy with an unknown cause responded favorably to the third AED compared with only 7.8% of the cohort that had epilepsy with a structural/metabolic cause. Children with a remote brain insult had a significantly higher likelihood of favorable outcome with serial AEDs than those with other structural abnormalities.SignificanceEtiology is an important determinant of pharmacoresistance in nonsyndromic focal epilepsy. Surgical evaluation should be considered after failure of 1–2 AEDs in those who have epilepsy with structural causes, excluding remote brain insults. Conversely, as surgical success is lower with normal MRI or more diffuse brain insults, it appears reasonable to hold off surgical evaluation until 2–3 AEDs have failed in such children.     

Prediction of rhythmic and periodic EEG patterns and seizures on continuous EEG with early epileptiform discharges

BackgroundContinuous EEG (cEEG) is necessary to document nonconvulsive seizures (NCS), nonconvulsive status epilepticus (NCSE), as well as rhythmic and periodic EEG patterns of ‘ictal–interictal uncertainty’ (RPPIIU) including periodic discharges, rhythmic delta activity, and spike-and-wave complexes in neurological intensive care patients. However, cEEG is associated with significant recording and analysis efforts. Therefore, predictors from short-term routine EEG with a reasonably high yield are urgently needed in order to select patients for evaluation with cEEG.ObjectiveThe aim of this study was to assess the prognostic significance of early epileptiform discharges (i.e., within the first 30 min of EEG recording) on the following: (1) incidence of ictal EEG patterns and RPPIIU on subsequent cEEG, (2) occurrence of acute convulsive seizures during the ICU stay, and (3) functional outcome after 6 months of follow-up.MethodsWe conducted a separate analysis of the first 30 min and the remaining segments of prospective cEEG recordings according to the ACNS Standardized Critical Care EEG Terminology as well as NCS criteria and review of clinical data of 32 neurological critical care patients.ResultsIn 17 patients with epileptiform discharges within the first 30 min of EEG (group 1), electrographic seizures were observed in 23.5% (n = 4), rhythmic or periodic EEG patterns of ‘ictal–interictal uncertainty’ in 64.7% (n = 11), and neither electrographic seizures nor RPPIIU in 11.8% (n = 2). In 15 patients with no epileptiform discharges in the first 30 min of EEG (group 2), no electrographic seizures were recorded on subsequent cEEG, RPPIIU were seen in 26.7% (n = 4), and neither electrographic seizures nor RPPIIU in 73.3% (n = 11). The incidence of EEG patterns on cEEG was significantly different between the two groups (p = 0.008). Patients with early epileptiform discharges developed acute seizures more frequently than patients without early epileptiform discharges (p = 0.009). Finally, functional outcome six months after discharge was significantly worse in patients with early epileptiform discharges (p = 0.01).ConclusionsEpileptiform discharges within the first 30 min of EEG recording are predictive for the occurrence of ictal EEG patterns and for RPPIIU on subsequent cEEG, for acute convulsive seizures during the ICU stay, and for a worse functional outcome after 6 months of follow-up.This article is part of a Special Issue entitled Status Epilepticus.     

Paroxysmal activity and seizures associated with sleep breathing disorder in children: A possible overlap between diurnal and nocturnal symptoms

PurposeSleep breathing disorders (SBD) can trigger paroxysmal events. We recently found a higher percentage of paroxysmal activity (PA) in a sample of Italian children with obstructive sleep apnea syndrome (OSAS) and no history of epilepsy. The signs of nocturnal seizures can overlap with sleep respiratory events. The aim of this study was to confirm the high frequency of PA or interictal epileptiform discharges (IEDs) during sleep in a cohort of Spanish children who underwent polysomonography (PSG) for suspected SBD and to ascertain the eventual presence of seizures by means of a video-PSG with an extended electroencephalogram (EEG).MethodsPSG was performed in a population of children with no previous history of epileptic seizures recruited prospectively for suspected OSAS from January to December 2007. Recordings included at least 13 EEG channels.ResultsIn total, 25 children (mean age, 6.6 ± 3.8 years, 14 males) were diagnosed with SBD, and 4/25 (16%) children met the criteria for OSAS and epilepsy, with IEDs and/or seizures during sleep. We diagnosed benign epilepsy with centro-temporal spikes in 2 cases, partial symptomatic epilepsy in one, and nocturnal frontal lobe epilepsy in another, while we found PA in 2 patients. The body mass index and the apnea–hypopnea index were significantly higher in children without IEDs/PA.ConclusionsOur study demonstrated a close relationship between pediatric SBD, PA during sleep, and epilepsy that may aggravate the prognosis of SBD. Due to the possibility of an overlap of symptoms, a video-PSG with extended EEG montage is necessary.     

REM rebound and CPAP compliance

Objective/BackgroundThe objective of this study was establish if rapid-eye-movement (REM) rebound on first exposure to continuous positive airway pressure (CPAP) is associated with CPAP compliance. A rebound or drastic increase in REM sleep in response to initial CPAP exposure is associated with improvement in the subjective quality of sleep. We wished to determine if REM rebound was also associated with increased CPAP compliance.MethodsSplit night polysomnographic studies carried out in a one-and-a-half year period were examined for REM rebound and slow wave sleep (SWS) rebound. Compliance with CPAP according to percentage of days used and percentage of days used for more than 4 h was determined at 30, 60, and 120 days and compared between groups with and without REM rebound and then between groups with and without SWS rebound. Multivariate regression models were constructed to determine factors that were associated with increasing CPAP compliance.ResultsCPAP compliance was greater for those with REM rebound than those without REM rebound at all time periods, but significantly so only for total percentage of days used at 30 days (86.7 ± 46.7, 96.7 vs. 56.7 [median ± 1st quartile, 3rd quartile] ± 32.5, 90.0; p = 0.04) and 60 days (78.3 ± 37.5, 93.4 vs. 50.0 ± 25.0, 80.9; p = 0.03). There was no difference in CPAP compliance for SWS rebound and there were no SWS rebound groups. Only the presence of REM rebound was associated with increased compliance with CPAP with neither SWS rebound nor diagnostic AHI being significantly associated with CPAP compliance.ConclusionsThe presence of REM rebound, but not SWS rebound, on initial CPAP exposure is associated with early CPAP compliance. This increased compliance is not explained by severity of sleep apnea as measured by AHI.     

Impact of sleep on the localizing value of video EEG in patients with refractory focal seizures – A prospective video-EEG with EOG and submental EMG study

ObjectivesTo examine the role of sleep and its stages on the localizing value of video EEG in the evaluation of refractory focal seizures.MethodsVideo-electroencephalographic (VEEG) evaluation with additional polygraphic recording was carried out for 70 consecutive patients with refractory focal epilepsy, undergoing pre-surgical evaluation, over a two-year period. Localization of video EEG for each seizure was made based on clinical, ictal and interictal data. Seizure localization in each patient was assessed for concordance with MRI and other imaging data (SPECT, PET) for both wake and sleep seizures. Interictal discharges in sleep and wake were similarly compared for concordance with imaging data.ResultsA total of 608 seizures were recorded in 70 patients, 289 in sleep. Overall, concordance with imaging data was found in 218 out of 322 wake seizures (67.8%) and in 157 out of 286 sleep seizures (54.8%) (p = 0.0314). On analyzing the subset of patients with seizures recorded in both wake and sleep states (total 279 seizures recorded, 113 out of sleep), concordance was observed in 93 out of 166 (56%) wake seizures and in 80 out of 113 (70.7%) sleep seizures (OR 2.03, 95% CI 1.17 to 3.56; p 0.007). Interictal discharges were more common and more precisely localizing in sleep, mostly in stage N2.ConclusionsThis prospective VEEG-PSG study demonstrates the role of sleep versus wake state in the localizing value of different components of long-term VEEG recording for patients with medically refractory epilepsy. Our findings show that while wake state ictal EEG has more localizing value in a mixed group of patients, sleep ictal and interictal EEG is significantly more useful in patients who have seizures recorded both during wake and sleep states. In addition, interictal discharges recorded during NREM sleep have high localizing value.SignificanceThis is only the second study elucidating the effect of sleep on the localizing value of video-electroencephalographic evaluation of patients with medically refractory focal epilepsy; mainly revealing high value of sleep interictal discharges and that sleep ictal recording has two times higher localizing value than wake ictal recording, among patients in whom seizures are recorded in both states.     

Medical outcome in epilepsy patients of young adulthood—A 5-year follow-up study

The appearance of new anti-epileptic drugs (AED) during the last decade has provided neurologists and their patients with a greater choice, but the proof for their superiority over traditional AEDs is sparse, especially their use in adolescence and young adulthood. We studied a group of young adults (18–27 years) with epilepsy and compared their situation in 2004 with those 5 years earlier.Materials and methodsThe participants (n = 97) answered questionnaires regarding seizure-frequency, AED, side-effects and quality-of-life. Information was also taken from medical records.ResultsThe use of new generation AEDs increased during the 5-year study period, particularly among women. However seizure frequency had not changed significantly over time, and compared to men the effectiveness in controlling seizures was lower in women. The participants reported normal quality-of-life (QOL), which may indicate that the increase in number of AEDs to choose from actually improved the situation for these young adults with epilepsy. Frequency of seizures and cognitive side-effects of AEDs were associated with a lower QOL.ConclusionsMore women than men seem to be treated with new AEDs, and that the increase in use of new AEDs does not reduce seizure frequency in young adulthood. The effectiveness in controlling seizures seems to be lower in women in the age group studied. Further studies are required to better understand how epilepsy related factors interact.     

Comparison of supine-only and REM-only obstructive sleep apnoea

ObjectivesThe effect of body position and sleep state on sleep apnoea have major clinical implications in the management of patients, yet are infrequently reported in the scientific literature. The aim of this study was to compare and contrast the prevalence and severity of supine-only and rapid eye movement (REM)-only obstructive sleep apnoea (OSA) in a population.MethodsProspective cohort analysis of the influence of supine body position and REM sleep on the severity of apnoea in 100 consecutive patients with OSA (apnoea–hypopnoea index [AHI] > 5) using attended polysomnography with continuous digital monitoring in an accredited sleep laboratory. Supine-only OSA was defined as a supine:non-supine AHI ratio of >2:1 and non-supine AHI <5 events/h. REM-only OSA was defined as an REM:non-REM ratio of >2:1 and non-REM AHI <5 events/h.ResultsSupine sleep time represented a greater proportion of total sleep time than REM sleep time (40% vs 13%). The prevalence of supine-only OSA was more than twofold greater than that of REM-only OSA (23% and 10%, respectively). The supine-only group had greater overall AHI (mean 12.6 ± 6.1 vs 7.2 ± 2.2 events/h; P < 0.01) than the REM-only group. No significant differences in gender, age, or sleepiness were found between the two groups.ConclusionsSupine-only OSA is more common and is associated with a greater AHI than REM-only OSA.     

Circadian patterns of generalized tonic-clonic evolutions in pediatric epilepsy patients

ObjectiveTo investigate the sleep/wake, day/night, and 24-h periodicity of pediatric evolution to generalized tonic–clonic seizures (GTC).MethodsCharts of 407 consecutive patients aged 0–21 years undergoing continuous video-EEG monitoring for epilepsy were reviewed for the presence of GTC evolution. Seizures were characterized according to 2001 ILAE terminology. Charts were reviewed for EEG seizure localization, MRI lesion, and for seizure occurrence in 3-h time blocks, out of sleep or wakefulness, and during the day (6 AM–6 PM) or night. Analysis was done with binomial testing. Regression models were fitted using generalized estimating equations with patients as the cluster level variable.Results71 patients (32 girls, mean age 12.63 ± 5.3 years) had 223 seizures with GTC evolution. Sleep/wake seizure distribution predicted tonic–clonic evolution better than time of day, with more occurring during sleep (p < 0.001). Tonic–clonic evolution occurred most frequently between 12–3 AM and 6–9 AM (p < 0.05). Patients with generalized EEG onset had more tonic–clonic evolution between 9 AM and 12 PM (p < 0.05). Patients with extratemporal focal seizures were more likely to evolve during sleep (p < 0.001); this pattern was not found in patients with temporal or generalized seizure onset on EEG. Patients without MRI lesions were more likely to evolve between 12 AM and 3 AM (p < 0.05), in the sleeping state (p < 0.001), and at night (p < 0.05). Logistic regression revealed that sleep and older patient age were the most important predictors of GTC evolution.ConclusionGTC evolution occurs most frequently out of sleep and in older patients. Our results may assist in seizure prediction, individualized treatment patterns, and potentially complication and SUDEP prevention.     

Effect of cortical cooling on interictal epileptiform activities

ObjectiveTo determine if applying chilled solution to exposed cerebral cortex can reduce interictal epileptiform activities in patients during surgery.MethodsElectrocorticography was used to record the epileptiform activity of 12 patients (ages 18–53) undergoing cortical mapping and resection surgery. Interictal spikes were counted at baseline and compared with spikes after applying room temperature and chilled Lactated Ringer's or normal saline solution.ResultsCortical irrigation with 150-cm³, chilled (4 °C) normal saline solution reduced the mean number of interictal spikes from 11.46 to 4.87 spikes per minute (p = 0.04). There was no significant reduction in the epileptic spike frequency when room temperature normal saline was used.ConclusionThe application of chilled solution directly to the cortex can reduce interictal epileptiform activities, suggesting that seizure potential can be suppressed to avoid evoked seizures during intraoperative surgery.     

Evaluating the use of prolonged video-EEG monitoring to assess future seizure risk and fitness to drive

ObjectiveThe use of prolonged video-electroencephalography monitoring (VEM), rather than routine electroencephalography (EEG), in predicting the risk of future seizures in patients with epilepsy is not well studied. A longer period of monitoring could be more likely to capture either ictal or interictal epileptiform activity. This information may better assist clinical decision making on driving fitness. The goal of this study was to evaluate the use of 6-hour prolonged VEM versus routine EEG in the assessment of future seizure risk and driving fitness for patients with epilepsy.MethodsData on consecutive patients referred for 6-hour prolonged VEM were retrospectively analyzed. Criteria were developed that combined EEG findings and clinical factors to determine each patient's fitness to drive. Seizure relapse outcomes were followed over 2 years.ResultsOf 34 patients, 27 were considered safe to drive following prolonged VEM. Five (19%) of these 27 patients had seizure relapses; all had an obvious precipitant(s) identified including sleep deprivation, excessive alcohol, and missed medication doses. Seven of the 34 patients were deemed unsafe to drive. All seven (100%) had seizure relapses, with unprovoked seizures in four patients. The relative risk of seizure in patients deemed unfit to drive was 5.4 (P = 0.00015). If only the routine EEG component of the recordings were used with the criteria, the relative risk would have been 3.4 (P = 0.037), with nearly double the number of active drivers having seizures. The majority of patients (76%) in this study had idiopathic generalized epilepsy, with a relative seizure risk of 4.0 (P = 0.002) for patients deemed unfit to drive in this subgroup. The focal epilepsy group was small (eight patients) and did not quite achieve statistical significance.ConclusionSix-hour VEM improves the evaluation of driving fitness by better predicting the risk of subsequent seizure relapse for idiopathic generalized epilepsy and possibly focal epilepsy. Prolonged monitoring is superior to routine EEG. Ongoing avoidance of seizure-provoking factors remains paramount to driving safety.     

An audit of the presurgical evaluation and patient selection for extratemporal resective epilepsy surgery in a resource-poor country

PurposeThe selection of ideal candidates for extratemporal resective epilepsy surgery is a challenge in resource-poor countries because of the limited presurgical diagnostic facilities and their affordability. To audit the presurgical evaluation strategy and selection for extratemporal resective epilepsy surgery in a resource-poor region.MethodsFrom the prospective database maintained at an epilepsy surgery center in southern India, we reviewed the data of consecutive patients who underwent presurgical evaluation from January 2005 through December 2008 for antiepileptic drug-resistant focal epilepsies emanating from the frontal, parietal and occipital lobes. Out of 285 patients, only 71 (24.9%) underwent resective surgery; the remaining 214 (75.1%) patients could not be selected for surgery. We inquired the reasons for their exclusion from surgery.ResultsThe difference in the rates of seizure-free outcome between surgical and non-surgical groups was highly significant (73.2% vs. 7.7%, P < 0.0005). The major reasons for exclusion from surgery were normal MRI in 107 (50%), inability to afford invasive EEG monitoring in 40 (18.7%) and lesion location adjacent to eloquent cortical areas in 27 (12.6%) patients. While clustering of seizures and presence of preoperative neurological deficits favored surgical selection, the presence of secondary generalized seizures and discordant interictal epileptiform abnormalities were associated with exclusion from surgery.ConclusionsWe conclude that, in a resource-poor country, ideal candidates for extratemporal resective epilepsy surgery are those with well-circumscribed lesions not adjoining eloquent cortical areas. In such patients, concordant EEG findings and absence of preoperative secondary generalized seizures reinforce selection for surgery.     

Sleep in women: Normal values for sleep stages and position and the effect of age, obesity, sleep apnea, smoking, alcohol and hypertension

ObjectivesTo define normal values for total sleep time, sleep latency, sleep efficiency, sleep stages and sleeping positions in women and to investigate how sleep is affected by age, obesity, sleep apnea, smoking, alcohol dependency and hypertension.MethodsIn a population-based study, 400 Swedish women aged 20–70 years with over-sampling of snorers were investigated using overnight in-home polysomnography. All results are weighted.ResultsThe mean normal total sleep time was 392 min, sleep latency 22 min and sleep efficiency 82%. Women spent 31 min in sleep stage 1, 244 min in stage 2, 41 min in stage 3/4 and 76 min in rapid eye movement (REM) sleep. They spent 41% of their sleep time in the supine position, 50% in the lateral position and 9% in the prone position. Multivariate analyses revealed that sleep efficiency was lower in older women and in women with hypertension. Sleep latency was short in women with severe sleep apnea and long in smokers, alcohol-dependent and hypertensive women. Sleep stage 3/4 was inversely related to age and body mass index. Less REM sleep occurred in alcohol-dependent women. Women younger than 45 years old slept a mean of 42% in the lateral position while women of 45 years and older slept 57% in the lateral position (p < 0.001).ConclusionsIn this population-based study of women, we present normal values for sleep stages and sleeping position. We conclude that age, body mass index, obstructive sleep apnea, smoking, alcohol and hypertension reduce sleep quality. With age, women spend more time sleeping in the lateral position.     

REM sleep characteristics of nightmare sufferers before and after REM sleep deprivation

ObjectivesTo examine whether disrupted regulation of REM sleep propensity is implicated in nightmare (NM) pathophysiology.BackgroundHeightened REM propensity induced by REM sleep deprivation is belied by increases in REM %, REM density and the dreamlike quality of dream mentation during post-deprivation recovery sleep. Compromised regulation of REM sleep propensity may be a contributing factor in the pathophysiology of frequent NMs.MethodsA preliminary study of 14 subjects with frequent NMs (?1 NM/week; 27.6 ± 9.9 years) and 11 healthy control subjects (<1 NM/month; 24.3 ± 5.3 years) was undertaken. Subjects completed home sleep/dream logs and underwent three nights of polysomnographic recording with REM sleep deprivation on night 2. Group differences were assessed for a battery of REM sleep and dream measures on nights 1 and 3.ResultsSeveral measures, including #skipped early-night REM periods, REM latency, REM/NREM cycle length, early/late REM density,REM rebound, late-night REM% and dream vividness, suggested that REM sleep propensity was abnormally low for the frequent NM group throughout the 3-day study.ConclusionsFindings raise the possibility that REM anomalies recorded from NM sufferers sleeping in the laboratory environment reflect a disruption of one or more endogenous regulators of REM sleep propensity.     

Analysis of 24-hour heart rate variations in patients with epilepsy receiving antiepileptic drugs

ObjectiveThe goal of the study described here was to evaluate interictal heart rate variability (HRV) in young patients with epilepsy, a patient population in whom sudden unexpected death in epilepsy (SUDEP) is known to be more common.MethodsTwenty-four-hour ambulatory ECG Holter recordings of 37 patients (15–40 years old) and 32 healthy controls were compared.ResultsAll of the time domain indices (SDNN, SDANN, RMSSD, and HRV triangular index) were significantly suppressed (P < 0.001), and there was a marked reduction in parasympathetic tone (reduced HF_nu, P < 0.001) and an increase in sympathetic tone (increased LF_nu and LF/HF ratio, P < 0.001) in the patient group. Stepwise linear regression analysis revealed that polytherapy and epilepsy duration > 10 years were independent variables associated with a reduction in SDNN.ConclusionOur data suggest that the major determinants of suppressed SDNN are polytherapy and epilepsy duration > 10 years. Analysis of spectral measures of frequency domain indices suggests that an increased sympathetic tone in association with a decreased parasympathetic tone may constitute the mechanism underlying SUDEP in young people with epilepsy.