Neonatal seizures and brain damage

There are four unresolved clinical issues at bedside with respect to the recognition, differential diagnosis, prognosis, and treatment of infants who present with seizures. There is also an overriding fifth question which bridges these four clinical issues, based on a laboratory researcher's perspective at the "bench". Given the increasing understanding of the neurobiologic and pathophysiologic explanations for seizures in animal models, one must consider the question of whether neonatal seizures cause brain injury or are a surrogate of injury resulting from other etiologies.

Infantile Epileptic Encephalopathy with Hypsarrhythmia (Infantile Spasms/West Syndrome)

Infantile spasms is a unique disorder peculiar to infancy and early childhood. In this article, the clinical manifestations and electroencephalographic features of the disorder are described. The possible pathophysiologic mechanisms underlying infantile spasms and the relation of this disorder to other childhood encephalopathies are discussed. Finally, the treatment of patients with infantile spasms and their long-term outcome are briefly reviewed.

Postoperative pseudoepileptic seizures in a known epileptic: complications in recovery

A 47-yr-old woman underwent general anaesthesia for a squint correction. She had previously suffered a cerebral venous thrombosis, presenting as grand mal seizures during recovery from general anaesthesia for minor surgery. Subsequently, she was affected by Jacksonian limb seizures and petit mal epilepsy and had required long-term rehabilitation, and anticonvulsant and anticoagulant therapy. On arrival in recovery on this occasion, with a laryngeal mask airway (LMA) in place, she started to convulse. The seizures were initially treated with midazolam i.v., but they recurred. Whilst observing the seizure pattern and excluding the differential diagnoses, evidence emerged that psychological factors had played a large part in her clinical picture. Her differential diagnosis had recently been amended to include 'pseudoseizures'. A firm, supportive approach caused the 'convulsions' to cease within a few hours.

Recombinant AAV-mediated expression of galanin in rat hippocampus suppresses seizure development

Galanin, a 29- or 30-amino acid neuropeptide, has been implicated in the modulation of seizures. In this study, we constructed a recombinant adeno-associated viral (AAV) vector to constitutively over-express galanin (AAV-GAL). The vector mediated efficient transduction of HEK 293 cells in vitro and robust galanin expression in vivo when injected into the rat dorsal hippocampus. Rats were administered kainic acid intrahippocampally 2.5 months following AAV-GAL or empty vector (AAV-Empty) injection to study the effect of vector-mediated galanin over-expression on seizures. AAV-GAL-injected rats showed a decreased number of seizure episodes and total time spent in seizures compared to AAV-Empty rats, despite similar latencies to development of the first EEG seizure and similar levels of neuronal damage in the CA3 region for both groups. These data show that recombinant AAV mediates strong and stable over-expression of galanin when injected into the rat hippocampus resulting in a significant anticonvulsive effect. The seizure suppression effect of galanin expression in the hippocampus by viral vectors may lead to novel therapeutic strategies for the treatment and management of intractable seizures with focal onset such as temporal lobe epilepsy.

Attenuation of seizures and neuronal death by adeno-associated virus vector galanin expression and secretion

Seizure disorders present an attractive gene therapy target, particularly because viral vectors such as adeno-associated virus (AAV) and lentivirus can stably transduce neurons. When we targeted the N-methyl-D-aspartic acid (NMDA) excitatory amino acid receptor with an AAV-delivered antisense oligonucleotide, however, the promoter determined whether focal seizure sensitivity was significantly attenuated or facilitated. One potential means to circumvent this liability would be to express an inhibitory neuroactive peptide and constitutively secrete the peptide from the transduced cell. The neuropeptide galanin can modulate seizure activity in vivo, and the laminar protein fibronectin is usually secreted through a constitutive pathway. Initially, inclusion of the fibronectin secretory signal sequence (FIB) in an AAV vector caused significant gene product secretion in vitro. More importantly, the combination of this secretory signal with the coding sequence for the active galanin peptide significantly attenuated in vivo focal seizure sensitivity, even with different promoters, and prevented kainic acid-induced hilar cell death. Thus, neuroactive peptide expression and local secretion provides a new gene therapy platform for the treatment of neurological disorders.

The short-term outcome of seizure management by prehospital personnel: a comparison of two protocols

OBJECTIVE

To evaluate the impact of an emergency medical service protocol with reduced diazepam dose on the intubation rate of children with seizure activity treated by emergency medical service personnel and to evaluate the short-term outcome comparing 2 emergency medical service treatment protocols.

METHODS

Retrospective review of the emergency medical service and hospital databases of children 0-18 years with seizure activity. Prior to January 1996, the county emergency medical service protocol recommended a diazepam dose of 0.2-0.5 mg/kg i.v. or pr for termination of seizure activity (group 1). As of January 1996, the diazepam dose was reduced to 0.05-0.1 mg/kg i.v. or pr (group 2). Demographics, emergency medical service and emergency department interventions, and disposition data were abstracted.

RESULTS

1516 subjects met the enrollment criteria: 1003 (66%) in group 1 and 513 (34%) in group 2. Emergency medical service administered diazepam to 288 subjects: 189 (19%) in group 1 and 99 (19%) in group 2. Twenty (7%) of all treated subjects required intubation: 19 in group 1 and 1 in group 2 (relative risk 9.7, 95% CI 1.30-72.5). Mean diazepam dose was 0.17 mg/kg in group 1 and 0.13 mg/kg in group 2 (mean difference 0.04, 95% CI 0.02-0.06). No significant difference in the requirement for repeated anticonvulsant dose, complications, or emergency department interventions was noted. However, hospital admission rate was lower in group 2 (rate difference 0.06, 95% CI 0.01-0.11).

CONCLUSIONS

Our study demonstrated a reduction in intubation rate and a need for hospitalization in the reduced diazepam dose emergency medical service protocol. The reduction in the diazepam dose was effective in terminating the seizure activity and did not increase the risk of adverse events.

[Electric brain stimulation for epilepsy therapy]

Attempts to control epileptic seizures by electrical brain stimulation have been performed for 50 years. Many different stimulation targets and methods have been investigated. Vagal nerve stimulation (VNS) is now approved for the treatment of refractory epilepsies by several governmental authorities in Europe and North America. However, it is mainly used as a palliative method when patients do not respond to medical treatment and epilepsy surgery is not possible. Numerous studies of the effect of deep brain stimulation (DBS) on epileptic seizures have been performed and almost invariably report remarkable success. However, a limited number of controlled studies failed to show a significant effect. Repetitive transcranial magnetic stimulation (rTMS) also was effective in open studies, and controlled studies are now being carried out. In addition, several uncontrolled reports describe successful treatment of refractory status epilepticus with electroconvulsive therapy (ECT). In summary, with the targets and stimulation parameters investigated so far, the effects of electrical brain stimulation on seizure frequency have been moderate at best. In the animal laboratory, we are now testing high-intensity, low-frequency stimulation of white matter tracts directly connected to the epileptogenic zone (e.g., fornix, corpus callosum) as a new methodology to increase the efficacy of DBS ("overdrive method").

Paradoxical therapy in conversion reaction

Paradoxical therapy consists of suggesting that the patient intentionally engages in the unwanted behaviour such as performing compulsive ritual or wanting a conversion attack. In this study, the subjects were selected by the emergency unit psychiatrist from patients who were admitted to the emergency unit with pseudoseizure. The diagnoses was based on DSM-IV criteria. Paradoxical intention was applied to half of the 30 patients with conversion disorders; the other half were treated with diazepam in order to examine the efficiency of the paradoxical intention versus diazepam. In both groups the differences of the anxiety scores at the beginning of the study were found to be insignificant (z=1.08, p=0.28). Of the 15 patients who completed paradoxical intention treatment, 14 (93.3%) responded favorably to paradoxical intention. On the other hand of 15 patients who completed diazepam therapy, 9 (60%) responded well to therapy and 6 patients carried on their conversion symptoms at the end of 6 weeks. Paradoxical intention-treated patients appeared to have greater improvements in anxiety scores (z=2.43, p<0.015) and conversion symptoms (t=2.27, p=0.034) than the diazepam-treated patients. The results of the present study are encouraging in that paradoxical intention can be effective in the treatment of conversion disorder.

A comparison of drug treatment versus electrical stimulation for suppressing seizure activity

Currently, the management of seizure activity by using pharmacological approaches is in many cases successful. However, it is also known that some patients (up to 30%) do not respond to conventional treatment and are considered drug resistant. For this group other approaches are sometimes attempted, such as surgical resection (not reviewed here) or use of the ketogenic diet (also not reviewed here). More recently, though, procedures that utilize chronic electrical stimulation as a means for suppressing seizure events are being tried. Experiments based on electrical stimulation are being conducted in both animal models and in some limited human trials, but so far it has not been determined if chronic electrical stimulation is more or less effective than conventional drug therapy. This article reviews basic mechanisms of seizure activity, standard antiepileptic drugs (AEDs), and compares conventional AEDs to alternative approaches such as vagal nerve and deep brain stimulation.

Non-epileptic seizures: patients' understanding and reaction to the diagnosis and impact on outcome

RATIONALE

The study aim was to assess patients' understanding of and reaction to a diagnosis of non-epileptic attack disorder and to explore whether these factors contribute to outcome.

METHOD

Eighty-four patients diagnosed with non-epileptic attack disorder participated in the study. Participants answered questions about their seizures and understanding and reaction to the diagnosis. Data were collected by semi-structured telephone interview. Questionnaires were sent to the patients' general practitioners (GPs) to gather information regarding the patient's seizure status, prescription of anti-epileptic drugs and opinion regarding the diagnosis.

RESULTS

At the time of follow-up, a third of participants reported being seizure free. A total of 63% did not have a good understanding of the diagnosis, most were unclear about the precipitating factors and the most common reaction to the diagnosis was confusion. Many reported a negative impact of NES on everyday life. Sixty-five percent reported receiving psychological follow-up but the number of sessions attended was few (median 2). There was evidence that the reaction to the diagnosis contributed to the outcome in particular an angry outcome was associated with a poor prognosis. Ten GPs did not agree with the diagnosis.

CONCLUSION

Patients understanding and reactions to a diagnosis of non-epileptic attacks are important factors that should contribute to the development of more tailored treatment approaches.

Classification of seizures and epilepsy

The management of seizures and epilepsy begins with forming a differential diagnosis, making the diagnosis, and then classifying seizure type and epileptic syndrome. Classification guides treatment, including ancillary testing, management, prognosis, and if needed, selection of the appropriate antiepileptic drug (AED). Many AEDs are available, and certain seizure types or epilepsy syndromes respond to specific AEDs. The identification of the genetics, molecular basis, and pathophysiologic mechanisms of epilepsy has resulted from classification of specific epileptic syndromes. The classification system used by the International League Against Epilepsy is periodically revised. The proposed revision changes the classification emphasis from the anatomic origin of seizures (focal vs generalized) to seizure semiology (ie, the signs or clinical manifestations). Modified systems have been developed for specific circumstances (eg, neonatal seizures, infantile seizures, status epilepticus, and epilepsy surgery). This article reviews seizure and epilepsy classification, emphasizing new data.

More controversies on the treatment of psychogenic pseudoseizures: an addendum

There is no shortage of controversies when it comes to psychogenic pseudoseizures (PPS). In this addendum to the Iriarte et al. paper [Epilepsy Behav 4 (2003) 354], I review some controversial issues related to the treatment of PPS. First, I advocate the point that our first goal of therapy is not to attempt to stop the occurrence of PPS, but to ensure that patients and families have accepted that they do not suffer from epilepsy, because the most frequent cause of morbidity and mortality seen in these patients is related to their misdiagnosis as epilepsy patients and the resultant aggressive treatment in intensive care units. Remission of PPS should be our second goal! The second controversial point pertains to how long neurologists should continue to follow up patients after a diagnosis of PPS is reached, and I suggest some parameters to be used in reaching such decision. In the third controversial issue, I review the lack of communication between neurologists and psychiatrists exemplified by the misinterpretation by psychiatrists of the diagnostic value of video-EEG-telemetry studies and resulting mixed messages given to patients and families by neurologists and psychiatrists. The fourth controversial point pertains to the criteria to discontinue antiepileptic drugs after a diagnosis of PPS has been established. Finally, I discuss the timing of introducing a psychogenic cause during the presentation of the diagnosis to patient and family.

Controversies in the diagnosis and management of psychogenic pseudoseizures

Since the advent of video-EEG telemetry studies (V-EEG) neurologists have become increasingly aware of psychogenic pseudoseizures (PPS) given the relatively high prevalence of these events among patients seen in epilepsy centers. The use of V-EEG has been accepted as the gold standard study in establishing this diagnosis; some clinicians, however, have suggested that the clinical phenomena of PPS are so obvious in many patients that V-EEG may not be necessary. This is one of many controversial points that clinicians face when evaluating patients suspected of having PPS. In this article, we review some of these controversies, specifically the need for a video-EEG monitoring study in all patients suspected of having PPS and the role of induction protocols in the evaluation of PPS, the question of whether patients have any control over their events, and finally some of the therapeutic strategies for PPS including the need to limit these patients' driving privileges.

Suppression of limbic motor seizures by electrical stimulation in thalamic reticular nucleus

Kindling is a model of temporal lobe epilepsy in which repeated electrical stimulations in limbic areas lead to progressive increase of seizure susceptibility, culminating in generalized convulsions and the establishment of a permanent epileptic syndrome. We studied here the effect of stimulations in the thalamic reticular nucleus (TRN) on the development of seizures and hippocampal hyperexcitability in kindling elicited from the ventral hippocampus in rats. Animals given 12 kindling stimulations per day with 30-min intervals for 4 consecutive days developed generalized convulsions on day 4. Stimulations in TRN delivered simultaneously with those in the hippocampus induced marked suppression of seizure generalization. Similarly, the number of generalized seizures and the duration of behavioral convulsions were reduced when rats subjected to 40 kindling stimulations with 5-min intervals during about 3 h were costimulated in the TRN. The anticonvulsant effect of TRN costimulation was detected also when rats were test-stimulated in the hippocampus at 24 h and 2 and 4 weeks after the initial 40 hippocampal stimulations. Our data provide the first evidence that TRN stimulations can act to suppress limbic motor seizures in hippocampal kindling and suggest a new approach for seizure control in temporal lobe epilepsy.

Unusual early-onset Huntingtons disease

Huntington's disease is an autosomal dominant progressive neurodegenerative disorder characterized by involuntary movements, cognitive decline, and behavioral disorders leading to functional disability. In contrast to patients with adult onset, in which chorea is the major motor abnormality, children often present with spasticity, rigidity, and significant intellectual decline associated with a more rapidly progressive course. An unusual early-onset Huntington's disease case of an 11-year-old boy with severe hypokinetic/rigid syndrome appearing at the age of 2.5 years is presented. Clinical diagnosis was confirmed by polymerase chain reaction study of the expanded IT-15 allele with a compatible size of 102 cytosine-adenosine-guanosine repeats L-Dopa mildly ameliorated rigidity, bradykinesia, and dystonia. We conclude that Huntington's disease should be included in the differential diagnoses of regressive syndromes of early childhood.

BOLD fMRI activation induced by vagus nerve stimulation in seizure patients

OBJECTIVE

To identify the cerebral activated regions associated with the vagus nerve stimulation in epilepsy patients.

DESIGN

Blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI) was employed to detect areas of the brain activated by vagus nerve stimulation in five patients with documented complex partial seizures.

METHODS

Functional MRI was done on a GE 1.5T Echospeed horizon scanner. Before each patient entered the scanner, the vagal nerve stimulator was set to a specific ON-OFF paradigm so that the data could be analysed using a box-car type of design. The brains were scanned both anatomically and functionally. The functional images were corrected for head motion and co-registered to the anatomical images. Maps of the activated areas were generated and analysed using the brain mapping software, SPM99. The threshold for activation was chosen as p < 0.001.

RESULTS

All patients showed activation in the frontal and occipital lobes. However, activation in the thalamus was seen only in the two patients with improved seizure control.

CONCLUSIONS

BOLD fMRI can detect activation associated with vagus nerve stimulation. There may be a relation between thalamic activation and a favourable clinical outcome.

Oncologic emergencies

Cancer can lead to emergencies either due to the primary disease, or as a result of therapy. Appropriate diagnosis and rapid treatment of these conditions can result in survival of the patient. Whether chemotherapy is implemented or not, the clinician may be presented with a patient in need of emergency stabilization. Common occurring emergencies are related to effects of the cancer, ranging from immune dysfunction due to marrow infiltration to brain herniation due to increased intracranial pressure from neoplasia. Often adverse effects secondary to chemotherapy can cause emergency situations such as sepsis. Prompt diagnosis and treatment may result in a favorable outcome. Addressed in this chapter are commonly occurring emergencies and specific stabilizing treatments.

Epileptic seizure prediction and control

Epileptic seizures are manifestations of epilepsy, a serious brain dynamical disorder second only to strokes. Of the world's approximately 50 million people with epilepsy, fully 1/3 have seizures that are not controlled by anti-convulsant medication. The field of seizure prediction, in which engineering technologies are used to decode brain signals and search for precursors of impending epileptic seizures, holds great promise to elucidate the dynamical mechanisms underlying the disorder, as well as to enable implantable devices to intervene in time to treat epilepsy. There is currently an explosion of interest in this field in academic centers and medical industry with clinical trials underway to test potential prediction and intervention methodology and devices for Food and Drug Administration (FDA) approval. This invited paper presents an overview of the application of signal processing methodologies based upon the theory of nonlinear dynamics to the problem of seizure prediction. Broader application of these developments to a variety of systems requiring monitoring, forecasting and control is a natural outgrowth of this field.

Control of nerve agent-induced seizures is critical for neuroprotection and survival

This study evaluated the potency and rapidity of some anticholinergics (atropine, biperiden, and trihexyphenidyl) and benzodiazepines (diazepam and midazolam) as an anticonvulsant treatment against seizures induced by six nerve agents (tabun, sarin, soman, cyclosarin, VR, and VX) and summarized the relationship between anticonvulsant activity and nerve agent-induced lethality and neuropathology. Guinea pigs, previously implanted with cortical electrodes for EEG recording, were pretreated with pyridostigmine bromide (0.026 mg/kg im) 30 min prior to challenge with 2x LD50 dose (sc) of a given nerve agent; in a separate experiment, animals were challenged with 5x LD50 sc of soman. One minute after agent challenge the animals were treated im with 2 mg/kg atropine SO(4) admixed with 25 mg/kg 2-PAM Cl. Five minutes after the start of EEG seizures, animals were treated im with different doses of anticholinergics or benzodiazepines and observed for seizure termination. The time to seizure onset, the time to seizure termination, and 24-h lethality were recorded. The anticonvulsant ED50 of each drug for termination of seizures induced by each agent was calculated and compared. Brain tissue from animals that survived 24 h was examined for pathology. All drugs were capable of terminating seizure activity, with midazolam and trihexyphenidyl being significantly more potent than the other drugs, and midazolam being more rapid in controlling seizure than atropine, trihexyphenidyl, or diazepam against each agent. Seizures induced by sarin or VX required lower doses of all the test anticonvulsants. The dose of a given drug that was an effective anticonvulsant against a 2x LD50 challenge of soman was equally effective against seizures induced by a 5x LD50 challenge. All nerve agents were capable of producing neuropathology. Seizure control was strongly associated with protection against acute lethality and brain pathology.