Delirium and epilepsy

Delirium (a state of usually reversible global brain disfunction due to toxic, metabolic, or infectious causes) and epilepsy (a condition of spontaneous, recurrent paroxysmal electrical excitation or dysfunction) are becoming increasingly better understood, and hence easier to diagnose and treat. The clinical features of delirium predominantly involve subacute changes in cognition, awareness, and activity levels, behavioral disturbance, clouding consciousness, and sleep-wake cycle changes. In contrast, epilepsy involves the acute interruption of brain function, often with convulsive activity, falls, and injury. States that may share the clinical features of both, such as nonconvulsive epileptic states, are also important: the cause of brain derangement is one of excessive and abnormal electrical brain activity. In such conditions, the clinical manifestations may resemble states of delirium and confusion, and the absence of convulsive clinical activity is significant. Electroencephalography remains the diagnostic test of choice: it is essential for differentiating these two conditions, enabling the distinctly different treatments and epilepsy. Ongoing research and investigation are essential to better understand the abnormal brat mechanisms underlying delirium, and to develop better tools for objective diagnosis.

Neurologic outcomes in retinopathy-negative cerebral malaria survivors

OBJECTIVES

Patients surviving retinopathy-positive cerebral malaria (CM) are at high risk for the development of epilepsy, developmental disabilities, and behavioral abnormalities. We aimed to establish whether retinopathy-negative CM is also a risk factor for these outcomes.

METHODS

Between 2005 and 2007, survivors of CM and concurrently hospitalized controls in Blantyre, Malawi, were followed to assess the development of neurologic abnormalities. At discharge and every 3 months thereafter, incident cases of epilepsy and developmental disabilities were ascertained using screening questionnaires and confirmatory neurologic examinations. Incident cases of epilepsy and developmental disabilities were compared in retinopathy-negative CM survivors to controls and retinopathy-positive CM survivors.

RESULTS

Thirty-five retinopathy-negative CM survivors were enrolled. Their neurologic outcomes were compared to 132 retinopathy-positive CM survivors and 272 controls. Compared to survivors of retinopathy-positive CM, children without malaria retinopathy have an equal odds of adverse neurologic outcome (odds ratio [OR] = 1.0, 95% confidence interval [CI] 0.4-2.2). Eleven of 35 survivors of retinopathy-negative CM had at least 1 adverse neurologic outcome compared to 2 of 272 controls (OR 61.9, 95% CI 13.0-295.5). In retinopathy-negative CM survivors, a Blantyre Coma Scale score ≤ 1 on admission was associated with an adverse outcome.

CONCLUSIONS

Compared with controls, children surviving either retinopathy-negative or -positive CM are at similar high risk for adverse neurologic outcomes. Studies to evaluate preventive and therapeutic strategies in children with both retinopathy-negative and -positive CM are needed to improve mortality, morbidity, or both.

Proposition: limbic encephalitis may represent limbic status epilepticus. A review of clinical and EEG characteristics

Limbic encephalitis (LE) with waxing and waning neuropsychiatric manifestations including behavioral, personality, psychiatric, and memory changes can evolve over days to months. Many features of LE show remarkable overlap with the characteristics of mesial-temporal (limbic) status epilepticus (MTLSE or LSE). With LE, these prolonged impaired states are assumed not to be due to ongoing epileptic activity or MTLSE, because scalp EEGs usually show no epileptiform spike-wave activity; cycling behavioral and motor changes are attributed to LE; there may be little immediate improvement with antiepileptic drugs (AEDs); and of course, implanted electrodes are rarely used. Conversely, it is known that in pre-surgical patients with refractory limbic epilepsy, implanted electrodes have revealed limbic seizures that cannot be seen at the scalp. This paper assembles a chain of inferences to advance the proposition that refractory LE might represent LSE more often than is thought, and that implanted electrodes should be considered in some cases. We present two cases that suggest that LE was also LSE, one of which warranted implanted electrodes (case 1).

Electroencephalography in patients with cirrhosis

BACKGROUND & AIMS

Electroencephalography has not been completely quantified in patients with cirrhosis. We investigated the electroencephalogram (EEG) dynamics in patients with cirrhosis.

METHODS

We performed closed-eye EEGs on 175 patients with cirrhosis (age, 55 ± 11 years; 24% Child-Pugh class A, 48% class B, and 285 class C), conducted clinical and psychometric assessments for hepatic encephalopathy (HE), and followed the patients for 1 year. EEG characteristics were assessed in the frequency domain, in the frontal (F3-F4) and parietal (P3-P4) derivations. Intrahemispheric (frontoparietal, right, and left) and interhemispheric (F3-F4 and P3-P4) coherence were computed. The EEGs of 50 healthy volunteers (age, 56 ± 17 years) served as controls.

RESULTS

Compared with controls, the EEGs of patients with cirrhosis had a reduced frequency in the posterior derivations (P3/P4 mean dominant frequency, 9.1 ± 1.8 and 8.9 ± 1.7 Hz vs 10.4 ± 1.3 and 10.2 ± 1.3 Hz, respectively; P < .01) and an increase in interhemispheric parietal relative coherence within the theta band (22.3% ± 5.5% vs 18.9% ± 3.5%; P < .01). These features were more prominent in patients with Child class C and in patients with a history of overt HE; they correlated with hyperammonemia and hyponatremia. The decrease in EEG frequency, along with the increase in interhemispheric theta coherence in the posterior derivations, was inversely associated with survival and the occurrence of overt HE during the follow-up period.

CONCLUSIONS

In patients with cirrhosis, alterations in the EEG were significantly associated with the severity of liver disease and HE; the EEG might be used in determining prognosis.

Obsessive-compulsive disorder in chronic epilepsy

There is a long-recognized association between obsessive-compulsive disorder (OCD) and chronic epilepsy, most notably refractory temporal lobe epilepsy (TLE). The literature documents this association with case reports, patient series, and some larger controlled studies that reveal that almost a quarter of patients with TLE exhibit OCD features, which may go unrecognized. Obsession features with ordering, symmetry, exactness, handwashing, and religiosity occur more often in persons with right- or left-sided epileptic foci than in those with idiopathic generalized epilepsies or controls. Neurobiological and social factors suggest abnormalities of the frontal-thalamic-pallidal-striatal-anterior cingulate-frontal circuits stemming from the observation that certain diseases, damage, or surgery along these circuits may produce or, conversely, reduce OCD in TLE. This review explores the literature on case reports, case series, and larger retrospective controlled studies and looks at the associations of epilepsy with OCD. Contemporary speculation on the theoretical neurobiological underpinnings provides some basis on how and where to direct treatment. Invasive deep brain stimulation has triggered recent controversy on newer treatment modalities.

Antiepileptic drugs modify power of high EEG frequencies and their neural generators

BACKGROUND

The clinical and molecular effects of antiepileptic drugs (AEDs) have been extensively investigated. Much less is known about their effects on human electrophysiology.

METHODS

Topographic analysis in the frequency domain has been used to analyze 104 electroencephalogram (EEG) epochs of 52 patients presenting with first-ever generalized seizure, with normal MRI and EEG. Patients were treated with valproate, arbamazepine, or lamotrigine in monotherapy (each group n = 13). Thirteen patients without medication served as a control group.

RESULTS

Carbamazepine and lamotrigine, both sodium-channel modulators, altered brain topography in the gamma range in the same frequency bands (50-60 Hz). Valproate, which has multiple actions on sodium and calcium channels as well as GABA turnover, modified brain topography in the low gamma range (30-40 Hz). No such changes were found in the control group. For all AEDs, the neural generators were shifted more anteriorly in medial temporal through to inferior frontal regions.

CONCLUSION

Decreased gamma-power and anterior shift of neural generators after AED introduction reflect AED influence on human electrophysiology.

Blantyre Malaria Project Epilepsy Study (BMPES) of neurological outcomes in retinopathy-positive paediatric cerebral malaria survivors: a prospective cohort study

BACKGROUND

Cerebral malaria, a disorder characterised by coma, parasitaemia, and no other evident cause of coma, is challenging to diagnose definitively in endemic regions that have high rates of asymptomatic parasitaemia and limited neurodiagnostic facilities. A recently described malaria retinopathy improves diagnostic specificity. We aimed to establish whether retinopathy-positive cerebral malaria is a risk factor for epilepsy or other neurodisabilities.

METHODS

Between 2005 and 2007, we did a prospective cohort study of survivors of cerebral malaria with malaria retinopathy in Blantyre, Malawi. Children with cerebral malaria were identified at the time of their index admission and age-matched to concurrently admitted children without coma or nervous system infection. Initially matching of cases to controls was 1:1 but, in 2006, enrolment criteria for cerebral malaria survivors were revised to limit inclusion to children with cerebral malaria and retinopathy on the basis of indirect ophthalmoscopic examination; matching was then changed to 1:2 and the revised inclusion criteria were applied retrospectively for children enrolled previously. Clinical assessments at discharge and standardised nurse-led follow-up every 3 months thereafter were done to identify children with new seizure disorders or other neurodisabilities. A Kaplan-Meier survival analysis was done for incident epilepsy.

FINDINGS

132 children with retinopathy-positive cerebral malaria and 264 age-matched, non-comatose controls were followed up for a median of 495 days (IQR 195-819). 12 of 132 cerebral malaria survivors developed epilepsy versus none of 264 controls (odds ratio [OR] undefined; p<0·0001). 28 of 121 cerebral malaria survivors developed new neurodisabilities, characterised by gross motor, sensory, or language deficits, compared with two of 253 controls (OR 37·8, 95% CI 8·8-161·8; p<0·0001). The risk factors for epilepsy in children with cerebral malaria were a higher maximum temperature (39·4°C [SD 1·2] vs 38·5°C [1·1]; p=0·01) and acute seizures (11/12 vs 76/120; OR 6·37, 95% CI 1·02-141·2), and male sex was a risk factor for new neurodisabilities (20/28 vs 38/93; OR 3·62, 1·44-9·06).

INTERPRETATION

Almost a third of retinopathy-positive cerebral malaria survivors developed epilepsy or other neurobehavioural sequelae. Neuroprotective clinical trials aimed at managing hyperpyrexia and optimising seizure control are warranted.

FUNDING

US National Institutes of Health and Wellcome Trust.

Nonepileptic seizures under levetiracetam therapy

We describe two patients with epilepsy who presented with nonepileptic seizures (NES) when started on levetiracetam (LEV), which disappeared or significantly decreased when LEV was discontinued. NES are traditionally attributed to psychic trauma often after physical or sexual abuse, whereas the psychiatric side effects of levetiracetam largely encompass depression, hallucinations, and psychosis. We conclude that NES are a rare side effect of LEV treatment and part of the spectrum of behavioral changes observed with LEV treatment.

Prognostic value of continuous EEG monitoring during therapeutic hypothermia after cardiac arrest

Introduction

Continuous EEG (cEEG) is increasingly used to monitor brain function in neuro-ICU patients. However, its value in patients with coma after cardiac arrest (CA), particularly in the setting of therapeutic hypothermia (TH), is only beginning to be elucidated. The aim of this study was to examine whether cEEG performed during TH may predict outcome.

Methods

From April 2009 to April 2010, we prospectively studied 34 consecutive comatose patients treated with TH after CA who were monitored with cEEG, initiated during hypothermia and maintained after rewarming. EEG background reactivity to painful stimulation was tested. We analyzed the association between cEEG findings and neurologic outcome, assessed at 2 months with the Glasgow-Pittsburgh Cerebral Performance Categories (CPC).

Results

Continuous EEG recording was started 12 ± 6 hours after CA and lasted 30 ± 11 hours. Nonreactive cEEG background (12 of 15 (75%) among nonsurvivors versus none of 19 (0) survivors; P < 0.001) and prolonged discontinuous "burst-suppression" activity (11 of 15 (73%) versus none of 19; P < 0.001) were significantly associated with mortality. EEG seizures with absent background reactivity also differed significantly (seven of 15 (47%) versus none of 12 (0); P = 0.001). In patients with nonreactive background or seizures/epileptiform discharges on cEEG, no improvement was seen after TH. Nonreactive cEEG background during TH had a positive predictive value of 100% (95% confidence interval (CI), 74 to 100%) and a false-positive rate of 0 (95% CI, 0 to 18%) for mortality. All survivors had cEEG background reactivity, and the majority of them (14 (74%) of 19) had a favorable outcome (CPC 1 or 2).

Conclusions

Continuous EEG monitoring showing a nonreactive or discontinuous background during TH is strongly associated with unfavorable outcome in patients with coma after CA. These data warrant larger studies to confirm the value of continuous EEG monitoring in predicting prognosis after CA and TH.

Epilepsy and obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) has long been associated with epilepsy. The link with temporal lobe (usually refractory) epilepsy (TLE) is particularly prominent. Of TLE patients, 10% to 22% of patients may have OCD, often underdiagnosed in the outpatient clinic. Data on the links include case reports, case series, and controlled studies. Three larger, controlled studies in TLE patients, using comprehensive epilepsy and OCD classifications, in aggregate, have noted the obsessive qualities of washing, symmetry/exactness, and ordering, with a greater preoccupation with certain aspects of religion, compared with controls or patients with idiopathic generalized epilepsy. TLE foci may be either left- or right-sided. Social and neurobiological factors are involved in OCD in TLE. The neurobiology implicates a pathophysiological or structural impairment of the orbitofrontal-thalamic, and frontothalamic-pallidal-striatal-anterior cingulate-frontal circuits. Discrete anatomic lesions in these pathways, or their surgical removal, may induce (or conversely) improve OCD in TLE patients.

Prognostication after cardiac arrest and hypothermia: a prospective study

OBJECTIVE

Current American Academy of Neurology (AAN) guidelines for outcome prediction in comatose survivors of cardiac arrest (CA) have been validated before the therapeutic hypothermia era (TH). We undertook this study to verify the prognostic value of clinical and electrophysiological variables in the TH setting.

METHODS

A total of 111 consecutive comatose survivors of CA treated with TH were prospectively studied over a 3-year period. Neurological examination, electroencephalography (EEG), and somatosensory evoked potentials (SSEP) were performed immediately after TH, at normothermia and off sedation. Neurological recovery was assessed at 3 to 6 months, using Cerebral Performance Categories (CPC).

RESULTS

Three clinical variables, assessed within 72 hours after CA, showed higher false-positive mortality predictions as compared with the AAN guidelines: incomplete brainstem reflexes recovery (4% vs 0%), myoclonus (7% vs 0%), and absent motor response to pain (24% vs 0%). Furthermore, unreactive EEG background was incompatible with good long-term neurological recovery (CPC 1-2) and strongly associated with in-hospital mortality (adjusted odds ratio for death, 15.4; 95% confidence interval, 3.3-71.9). The presence of at least 2 independent predictors out of 4 (incomplete brainstem reflexes, myoclonus, unreactive EEG, and absent cortical SSEP) accurately predicted poor long-term neurological recovery (positive predictive value = 1.00); EEG reactivity significantly improved the prognostication.

INTERPRETATION

Our data show that TH may modify outcome prediction after CA, implying that some clinical features should be interpreted with more caution in this setting as compared with the AAN guidelines. EEG background reactivity is useful in determining the prognosis after CA treated with TH.

Identification of malaria retinopathy improves the specificity of the clinical diagnosis of cerebral malaria: findings from a prospective cohort study

The diagnosis of cerebral malaria (CM) is difficult to confirm in endemic regions with limited neurodiagnostics. Accurate diagnoses are critical for trials and outcomes studies. Findings from an autopsy-based study suggest that identifying malaria retinopathy in children satisfying the standard clinical case definition of CM improves our ability to accurately diagnose CM in vivo. In a post hoc analysis of a prospective exposure-control study to evaluate CM as a risk factor for epilepsy, we stratified children meeting the standard case definition by their retinopathy status (presence versus absence) and compared these groups for pre-existing risk factors for epilepsy. We also compared them to the concurrently enrolled, non-comatose controls. Children meeting the standard case definition of CM who lacked malaria retinopathy had a higher prevalence of pre-existing developmental problems and family history of epilepsy. This subset of patients may represent children with a pre-existing propensity to adverse neurologic symptoms and outcomes.

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): vitamin K, folic acid, blood levels, and breastfeeding: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy, including preconceptional folic acid use, prenatal vitamin K use, risk of hemorrhagic disease of the newborn, clinical implications of placental and breast milk transfer of antiepileptic drugs (AEDs), risks of breastfeeding, and change in AED levels during pregnancy.

METHODS

A 20-member committee evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and October 2007.

RESULTS

Preconceptional folic acid supplementation is possibly effective in preventing major congenital malformations in the newborns of WWE taking AEDs. There is inadequate evidence to determine if the newborns of WWE taking AEDs have a substantially increased risk of hemorrhagic complications. Primidone and levetiracetam probably transfer into breast milk in amounts that may be clinically important. Valproate, phenobarbital, phenytoin, and carbamazepine probably are not transferred into breast milk in clinically important amounts. Pregnancy probably causes an increase in the clearance and a decrease in the concentration of lamotrigine, phenytoin, and to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative.

RECOMMENDATIONS

Supplementing women with epilepsy with at least 0.4 mg of folic acid before they become pregnant may be considered (Level C). Monitoring of lamotrigine, carbamazepine, and phenytoin levels during pregnancy should be considered (Level B) and monitoring of levetiracetam and oxcarbazepine (as monohydroxy derivative) levels may be considered (Level C). A paucity of evidence limited the strength of many recommendations.

Neurophysiological investigations of hepatic encephalopathy: ISHEN practice guidelines

By studying neuronal activity through neuronal electrogenesis, neurophysiological investigations provide a functional assessment of the nervous system and, therefore, has been used for quantitative assessment and follow-up of hepatic encephalopathy (HE). The different clinical neurophysiological approaches can be classified depending on the function to explore and their sensitivity to HE. The reliable techniques are those that reflect cortical function, i.e., cognitive-evoked potentials (EPs) (P300 paradigm), electroencephalogram (EEG), visual EPs (latency>100 ms) and somatosensory EPs (SEPs) (latency between 25 and 100 ms). Short-latency EPs (brainstem acoustic EPs, SEPs of a latency<25 ms) are in principle insensitive to HE, but can disclose brainstem conduction deficits due to oedema. SEPs and motor EPs can disclose myelopathies. Because of its parallelism to the clinical examination, clinical neurophysiology can complement the neurological examination: (i) to provide evidence of HE in patients who have normal consciousness; (ii) to rule out, at least under some conditions, disturbances of consciousness due to other causes (e.g. drug-induced disturbances, non-convulsive status epilepticus) with the reservation that the mildest degrees of encephalopathy might be associated with an EEG pattern similar to that induced by drugs; and (iii) to demonstrate the worsening or, conversely improvement, of HE in the follow-up period.

Management issues for women with epilepsy-Focus on pregnancy (an evidence-based review): I. Obstetrical complications and change in seizure frequency: Report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the American Epilepsy Society

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including the risk of pregnancy complications or other medical problems during pregnancy, change in seizure frequency, the risk of status epilepticus, and the rate of remaining seizure-free during pregnancy. The committee evaluated the available evidence according to a structured literature review and classification of relevant articles. For WWE who are taking antiepileptic drugs (AEDs), there is probably no substantially increased risk (>2 times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (>1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. WWE should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84-92%) of remaining seizure-free during pregnancy. WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery.

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): obstetrical complications and change in seizure frequency: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy, including the risk of pregnancy complications or other medical problems during pregnancy in WWE compared to other women, change in seizure frequency, the risk of status epilepticus, and the rate of remaining seizure-free during pregnancy.

METHODS

A 20-member committee including general neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and February 2008.

RESULTS

For WWE taking antiepileptic drugs, there is probably no substantially increased risk (greater than two times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (greater than 1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. Seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84%-92%) of remaining seizure-free during pregnancy.

RECOMMENDATIONS

Women with epilepsy (WWE) should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high rate (84%-92%) of remaining seizure-free during pregnancy (Level B). However, WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery during pregnancy (Level C).

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): teratogenesis and perinatal outcomes: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy.

METHODS

Systematic review of relevant articles published between January 1985 and June 2007.

RESULTS

It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine and possible compared to phenytoin or lamotrigine. Compared to untreated WWE, it is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. It is probable that antiepileptic drug (AED) polytherapy as compared to monotherapy regimens contributes to the development of MCMs and to reduced cognitive outcomes. For monotherapy, intrauterine exposure to VPA probably reduces cognitive outcomes. Further, monotherapy exposure to phenytoin or phenobarbital possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of <7.

RECOMMENDATIONS

If possible, avoidance of valproate (VPA) and antiepileptic drug (AED) polytherapy during the first trimester of pregnancy should be considered to decrease the risk of major congenital malformations (Level B). If possible, avoidance of VPA and AED polytherapy throughout pregnancy should be considered to prevent reduced cognitive outcomes (Level B). If possible, avoidance of phenytoin and phenobarbital during pregnancy may be considered to prevent reduced cognitive outcomes (Level C). Pregnancy risk stratification should reflect that the offspring of women with epilepsy taking AEDs are probably at increased risk for being small for gestational age (Level B) and possibly at increased risk of 1-minute Apgar scores of <7 (Level C).

Seizures and status epilepticus in the intensive care unit

Persistent seizures and failure to regain consciousness following witnessed seizure activity require emergency neurological consultation. Although outcome is largely dependent on underlying cause, early maximal anticonvulsant therapy is critical to reducing morbidity. This review covers important concepts in the clinical and EEG diagnosis of status epilepticus, and discusses treatment algorithms for single and recurrent seizures, emphasizing the need to rationalize therapy depending on the presumed duration of seizure activity. The review takes the perspective of the neurological consultant in the intensive care unit, and considers all pharmacological approaches available to the intensivist as described in the current literature and from clinical experience.

Pregnancy registries in epilepsy: a consensus statement on health outcomes

Most pregnant women with epilepsy require antiepileptic drug (AED) therapy. Present guidelines recommend optimizing treatment prior to conception, choosing the most effective AED for seizure type and syndrome, using monotherapy and lowest effective dose, and supplementing with folate. The Epilepsy Therapy Project established the international Health Outcomes in Pregnancy and Epilepsy (HOPE) forum to learn more about the impact of AEDs on the developing fetus, particularly the role of pregnancy registries in studying AED teratogenicity. The primary outcome of interest in these registries is the occurrence of major congenital malformations, with some data collected on minor malformations. Cognitive and behavioral outcomes are often beyond the timeframe for follow-up of these registries and require independent study. The HOPE consensus report describes the current state of knowledge and the limitations to interpretations of information from the various sources. Data regarding specific risks for both older and newer AEDs need to be analyzed carefully, considering study designs and confounding factors. There is a critical need for investigations to delineate the underlying mechanisms and explain the variance seen in outcomes across AEDs and within a single AED.

Obstetric risks for women with epilepsy during pregnancy

Women with epilepsy (WWE) face particular challenges during their pregnancy. Among the several obstetric issues for which there is some concern and the need for further investigation are: the effects of seizures, epilepsy, and antiepileptic drugs on pregnancy outcome and, conversely, the effects of pregnancy and hormonal neurotransmitters on seizure control and antiepileptic drug metabolism. Obstetric concerns include preclampsia/eclampsia, preterm delivery, placental abruption, spontaneous abortion, stillbirth, and small-for-date babies in WWE whether or not they are taking antiepileptic drugs. The role of nutritional health elements, including body mass index, caloric and protein intake, vitamins and iron, and phytoestrogens, warrants further study. During the course of obstetric management, there is a need for a fuller understanding by neurologists of the risk-benefit calculations for various types and frequencies of fetal imaging, including CT, MRI, and ultrasound, as well as for the screening standards of care. As part of the Health Outcomes in Pregnancy and Epilepsy (HOPE) project, this expert panel provides a brief overview of these concerns, offers some approaches to management, and outlines potential areas for further investigation. More detailed information and guidelines are available elsewhere.

Lithium-induced confusional states: nonconvulsive status epilepticus or triphasic encephalopathy?

Lithium therapy can cause a confusional state by direct toxicity, precipitation of nonconvulsive status epilepticus, or by interplay with other neuroleptic medications to produce neuroleptic malignant syndrome or serotonin syndrome. These conditions resemble each other clinically, but EEG may help differentiate among them. We reviewed the EEG patterns with triphasic waves or rhythmic delta activity in lithium toxic patients and discuss clinical and EEG differentiation among syndromes. Lithium toxicity poses significant diagnostic challenges from EEG and clinical perspectives.

The EEG of status epilepticus

SUMMARY

Gastaut noted that there are as many forms of status epilepticus (SE) as there are seizure types. The pleomorphic EEG patterns reflect this wide variety of clinical types. The different electroclinical types of status epilepticus share EEG characteristics including rhythmic activity, epileptiform discharges, and often a waxing and waning evolution. Gray zones of interpretation exist in the form of runs of epileptiform periodic discharges, typically of lower frequency, and lesser temporal variability. In diagnosing SE, clinical correlation and response to parenteral anti-epileptic drugs (AEDs) are of particular importance. Accurate diagnosis of electroclinical SE type is essential, because it determines prognosis and dictates the intensity of therapeutic management. Some patients with benign forms of SE may benefit from nonparenteral treatment, and be followed up clinically and by spot EEGs. Conversely, intensive care unit management with anesthesia and continuous monitoring, and parenteral AEDs may be required for refractory convulsive SE.

Normal adult EEG and patterns of uncertain significance

A thorough understanding of a normal EEG is critical in defining those patterns that are abnormal. Because EEG is unique in the ability to support a clinical diagnosis of epilepsy, epileptiform patterns merit careful consideration. Certain benign patterns maybe epileptiform, yet can occur in healthy individuals without epilepsy. Understanding normal EEG and the benign variants will help to minimize over-interpretation and possibly avoid overtreatment of patients during routine clinical practice.

Electrophysiological Prognostication and Brain Injury from Cardiac Arrest

Anoxic coma after cardiorespiratory arrest warrants precocious investigation to establish probable outcome. Electroencephalogram (EEG) may uncover subclinical seizures; EEG grades have provided accurate prognosis of poor and favorable outcomes, but are weakest in those patients in between. Somatosensory evoked potentials now have proven benefit in accurately establishing a poor outcome (death or persistent vegetative state) when cortical responses (N20) are absent. These studies are particularly helpful when clinical examination of coma, early on, might yield uncertain prognosis (i.e., when brain stem reflexes are present). Combining clinical examination with electrophysiology has increasingly yielded multimodality approaches to early prognostication of coma after cardiorespiratory arrest, with more recent studies using event-related and middle-latency potentials showing promise for distinguishing good outcome (to consciousness), from awake but vegetative states. Further studies are warranted for this multimodality approach which, hopefully, may yield more widespread practical use of these testing modalities.

Neurologic prognosis and withdrawal of life support after resuscitation from cardiac arrest

OBJECTIVE

To study the impact of neurologic prognostication on the decision to withdraw life-sustaining therapies (LST) in comatose patients resuscitated after cardiac arrest.

METHODS

The authors prospectively studied a consecutive series of post-resuscitation comatose patients referred for neurologic prognostication at a single center for 4 years. For most patients, neurologic prognostication was not sought due to early death or rapid return to consciousness. Prognostication was based on Glasgow Coma Score (GCS) and Brainstem Reflex Score (BRS), with EEG and cortical evoked potentials (CEP), which were graded as benign, uncertain, and malignant. The outcomes were as follows: survivors (Group S), brain or cardiac death (Group D), and death from withdrawal of life sustaining therapy (Group W). In Group W, the time interval to withdrawal of LST was analyzed by EEG and CEP grades.

RESULTS

Of 58 patients studied, 10 were in Group S, 8 in Group D, and 40 in Group W. Initial median GCS and BRS was similar for all groups with significant improvement noted in Group S, but not in Group D or Group W. In Group W, CEP grade correlated with the median duration of continued therapy before a decision to withdraw LST: 7 days for benign CEP, 2 days for uncertain CEP, and 1 day for malignant CEP, p = 0.0004.

CONCLUSION

In patients with poor neurologic recovery early after resuscitation from cardiac arrest, physicians appear to use the cortical evoked potential grade to estimate prognosis. Cortical evoked potential grade correlated with the waiting time until life sustaining therapies were withdrawn after no improvement in neurologic examination was seen.

EEG monitoring in the intensive care unit

EEG recording in the intensive care setting presents a number of technical challenges. It is essential to differentiate artifact from pathophysiologic EEG changes that would suggest encephalopathy, epileptiform activity, or seizures. There are particular patterns typical of deepening encephalopathy, as well as, coma patterns that have diagnostic and prognostic significance (e.g., spindle coma, alpha coma, burst suppression activity, and triphasic waves). Epileptiform patterns, including periodic lateralized epileptiform discharges (PLEDs), bilateral independent periodic lateralized epileptiform discharges (BIPLEDs), and generalized periodic epileptiform discharges (GPEDs), present particular challenges as there is a gray-zone between interictal patterns and the evolving (usually faster) patterns of nonconvulsive seizures. Accurate use of EEG in the intensive care unit requires optimal EEG technical expertise in performing the study, and appropriate interpretation by a trained electrophysiologist.

Evaluation of a Novel EEG Preamplifier

SUMMARY

The authors performed initial clinical testing of a novel EEG transduction module (ETM), designed to record EEG signals from electrodes with high and unbalanced contact impedances. Twenty patients underwent two consecutive EEG studies. In the first, "experimental" study, electrodes were applied to an unprepared scalp, and the ETM performed initial signal transduction and pre-amplification. The second, "routine" EEG was acquired in the standard manner, with electrode contact impedances of 5 k Omega or less. Power spectral analysis was performed on all electrode signals from three experimental studies, and all studies were interpreted by three board-certified electro-encephalographers. Individual electrode impedances in the experimental studies ranged from 10 to 560 k Omega (mean 129 k Omega). Power spectra on 54 of 57 electrode signals analyzed were free of 60-Hz noise. The majority of experimental studies were technically adequate, and technical limitations were unrelated to the ETM. Interrater reliability of preparation-free and standard EEG interpretation was high. The ETM device is an effective "preparation-free" technology in the setting of a clinical EEG laboratory. It provided easily interpretable EEG signals free of 60-Hz noise, recorded from electrodes with high and unbalanced impedances placed on completely unprepared scalp with minimal electrode paste.

Clinical neurophysiologic monitoring and brain injury from cardiac arrest

Electrophysiologic testing continues to play an important role in injury stratification and prognostication in patients who are comatose after cardiac arrest. As discussed previously, however, the adage about treating whole patients, not just the numbers, is relevant in this situation. EEG and SSEP can offer high specificity for discerning poor prognosis as long as they are applied to appropriate patient populations. As discussed previously, EEG and SSEP patterns change during the first hours to days after cardiac arrest and negative prognostic information should not be based solely on studies performed during the first 24 hours. Both electrophysiologic techniques also are susceptible to artifacts that may worsen the electrical patterns artificially and suggest a falsely poor prognosis. EEG is suppressed by anesthetic agents and hypothermia, both of which may produce ECS and burst suppression. Patients who experience respiratory arrest from a toxic ingestion of narcotics or barbiturates, in particular, may present with high-grade EEG patterns initially. Many patients also receive anesthetic medications at the time of tracheal intubation, which may linger beyond their normal half-life in patients who have hepatic or renal insufficiency or concurrent use of interacting medications. SSEP is much less susceptible to sedative anesthetic agents, but hypothermia is demonstrated to prolong evoked potential latencies. As therapeutic hypothermia becomes more common after cardiac arrest, the effect of temperature on electrophysiologic testing needs to be taken into account. The publications discussed previously also emphasize the need to adjust the prognostic value of electro-physiologic tests to the pretest probability of meaningful neurologic recovery in individual patients. Clearly, grade I EEG patterns and normal N20 potentials indicate a much better prognosis in patients who have a short du-ration of cardiac arrest, short duration of coma after resuscitation, and when the studies are performed within the first few days. In patients who remain in coma days after resuscitation and lack appropriate brainstem reflexes, however, even the most normal appearing electrophysiologic patterns do little to change the overall prognosis. Aside from prognostication, electrophysiologic testing holds great promise in defining the basic anatomy and physiology of coma emergence after cardiac arrest. In addition, quantitative EEG and automated evoked potentials have the potential to render these tools less subjective and arcane and more applicable for monitoring patients in the period during and immediately after resuscitation. Quantitative EEG also has great potential asa tool to define the time window for neuroprotective intervention and the means to track the response to such therapies in real time.

The clinical features, diagnosis, and prognosis of nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) is a state of ongoing seizure activity for at least 30 minutes, with cognitive or behavioral changes, but without convulsive clinical manifestations. It requires EEG for confirmation. It has been categorized into groups having focal or generalized EEG epileptic activity; and by etiology and level of consciousness (which predict outcome). Points of contention include the evolving definition of what constitutes NCSE, various reasons for a delayed, missed, or misidentified diagnosis, and the optimal management of these conditions.

Reproductive health effects and teratogenicity of antiepileptic drugs

Women with epilepsy are less likely to bear children than women in the general population, and although this reduced fertility can be attributed in part to effects of the disease itself, the effects of antiepileptic drugs (AEDs), including changes in reproductive endocrine function, are also a factor. Conversely, some AEDs interact with oral contraceptives and can increase the risk for contraceptive failure and unplanned pregnancy. Women with epilepsy also have elevated rates of congenital anomalies and major malformations in their offspring, for which exposure of the developing fetus to AEDs taken by the mother appears to be responsible. In utero exposure to some AEDs may also be associated with increased risk for impaired cognitive function in the growing child. Clearly, possible long-term effects on reproductive health and pregnancy outcomes require careful attention when AED therapy is being considered for a patient with childbearing potential. Moreover, because AEDs are increasingly being used in therapy for other conditions such as migraine, bipolar disorder, and pain, it is not only the treatment of women with epilepsy that will be affected by these concerns.

Neurologic aspects of eclampsia

Eclampsia continues to be a significant cause of maternal and fetal death throughout the world. Neurologists have a specific role to play in the diagnosis and management of patients who have eclampsia, especially those who have recurrent seizures, raised intracranial pressure, and coma. Postpartum patients may be admitted to a neurology service when they present to the emergency department with seizures. The cornerstone of treatment has been blood pressure control and magnesium sulfate with its antivasospastic effect. Should this fail, antiepileptic drugs of proved efficacy, such as diazepam and phenytoin, can be used. Recent studies reveal genetic and mitochondrial defects in eclampsia, but further investigation is warranted to determine the complex underlying pathophysiologic interplay and the optimum prophylactic and therapeutic management.

The EEG in metabolic encephalopathy and coma

Excellent early work on stupor and coma can be found (particularly with regard to anoxia) in the work of Fischgold and Mathis (1959) in France, and Pamela Prior in England (1973a). These workers correlated deepening levels of coma with particular EEG patterns, and the suppression of EEG reactivity. Alpha frequency patterns in coma (alpha coma), spindle-like sleep patterns in coma (spindle coma) and "triphasic waves" are among the wide variety of endocrine disorders discussed in case reports and series leading to identification of particular EEG patterns. EEG correlations with prognosis are most reliable with cardiorespiratory arrest (CRA) with its consequent anoxic-ischemic insult. If etiology is known, EEG can often be a reliable predictor of outcome. EEG usually has little specificity with regards to etiology, but some patterns do favor particular diagnoses: for example, triphasic waves (TWs) are frequently seen with hepatic and renal insufficiency in young adults; spindle coma patterns are believed to indicate dysfunction at the brainstem level (Chatrian, 1990). EEG is most useful in differentiating organic from psychiatric conditions, in excluding nonconvulsive status epilepticus (NCSE), and in providing a rough guide as to the degree of cortical and subcortical dysfunction.

Mind, Brain, Body, and Soul: A Review of the Electrophysiological Undercurrents for Dr. Frankenstein

Mary Shelley's Frankenstein is perhaps the most famous work of medical science fiction. She and her husband, the poet Percy Shelley, were aware of nascent neuroscience experimentation and the effects of electricity on neuromuscular function. Such experiments generated theories of voluntary, involuntary, and unconscious neuromuscular function; animal electricity; and the anima--the human vital principle. In Germany and Italy, investigators were performing bizarre electrical experiments on animals and humans to "reanimate" lifeless limbs and bodies. These demonstrations and theories find expression in Frankenstein and provide models for Dr. Frankenstein and his creation.

Updates on the treatment of epilepsy in women

Epilepsy is a condition of the central nervous system that is characterized by recurrent seizures. The goal of management is to make patients seizure free without intolerable adverse effects from treatment. Men and women differ in their physiologic makeup and therefore have different needs that must be considered when attempting to attain this goal. There are special concerns for women of child-bearing years with regard to contraception, pregnancy, and teratogenicity that should be considered during counseling and selection of appropriate treatment. There are also emerging concerns about the interaction of antiepileptic drugs and endocrine function that can affect ovarian function, induce polycystic ovary (PCO)-like syndrome, and threaten fertility. Systemic adverse effects can have a negative impact on weight, cosmetic appearance, sexual function, and bone health. Individualized treatment coupling antiepileptic drug use and the specific phase of impact of the reproductive cycle must be considered in treatment selection. Important concerns regarding long-term therapy are being raised as there are more treatment options to consider because of the plethora of new antiepileptic drugs that are available, often with more favorable pharmacokinetics and different adverse event profiles. Also, sex hormone fluctuations during maturation may exacerbate seizures at particular points during the life cycle for women, including menarche, during menses, during pregnancy, or later in the perimenopausal years, often presenting a uniquely challenging aspect to treatment. As the number of available treatment options for epilepsy increases, the optimal goal for primary care physicians is to work as a team with obstetricians, gynecologists, and neurologists in an effort to ensure the best treatment of women with epilepsy.