Normal Electroencephalogram Research Articles

Isovoxel-Based Morphology of Hippocampi and Amygdalae: A Comparison of Manual and Automated Volume Measurements

This study evaluated the correlation between manual and automated morphometric measurements of hippocampi and amygdalae. Twenty-three patients with no history of seizures and normal electroencephalograms were examined with a standardized MRI protocol that included isovoxel volumetric acquisitions of the brain. Images were evaluated in axial-oblique plane to trace manually the grey matter contours of hippocampi and amygdalae obtaining their volumes. They were also processed automatically carrying out segmentation and sub segmentation aligning images (AC-PC) and standardizing them into Talairach space to obtain then comparable grey matter volumes. Tabled results were age, gender and volumes of each side from both, manual and automated measurements. Forward stepwise multiple regression analyses were carried out considering sex and age as independent and hippocampi-amygdalae as dependent variables. Linear regression analyses were then carried out considering for the total of cerebral hemispheres each manual measurement as independent and automatically obtained volumes as dependent variables. In the multiple regression analyses the following values were obtained: age-gender vs. manual measurements showed r=0.83; r(2)=0.69; adjustedr(2)=0.64; F(3,19)=14.36 while age-gender vs. automated values showed r=0.86; r(2)=0.74; adjustedr(2)=0.70; F(3,19)=18.81. Linear regression between manual and automated measurements for all hemispheres showed for hippocampus: r=0.97; r(2)=0.95; F(1,44)=896.59. For amygdala results were: r=0.94; r(2)=0.89; F(1,44)=391.11. The results of these analyses suggest that both manual and automated procedures of measurement are highly consistent. A regression between age and volumes of both hippocampus and amygdala was also noted.

Diazepam Versus Clobazam for Intermittent Prophylaxis of Febrile Seizures

To compare the effectiveness of intermittent clobazam versus diazepam therapy in preventing the recurrence of febrile seizures and assess adverse effects of each drug. This prospective randomized controlled trial was performed on neurologically normal children aged from 6 months to 5 years with a history of simple febrile seizures and normal electroencephalogram without any evidence of acute central nervous system infection. The patients were randomly prescribed with oral clobazam (37 cases) or diazepam (35 cases) when they developed a febrile disease. They were advised to use the medications during the first 48 h of the onset of fever. All the patients were monitored regarding developing seizure and adverse effects of the drugs. All patients were followed for 12 months. Overall, 243 episodes of fever occurred during the period, including 116 episodes in the clobazam group and 127 episodes in the diazepam group. Recurrence of seizures occurred in 2 (1.7%) subjects in the clobazam group, and in 4(3.1%) cases in the diazepam group. (P value=0.474). Twenty cases (54%) in the diazepam group and 5 (14.2%) cases in the clobazam group developed drowsiness and sedation during the follow-up period (P value=0.0001). Intermittent clobazam therapy seems advantageous to diazepam due to similar efficacy but significantly lower adverse effects such as drowsiness and sedation.

Epilepsy or Syncope? An Analysis of 55 Consecutive Patients with Loss of Consciousness, Convulsions, Falls, and No EEG Abnormalities

Patients with loss of consciousness and convulsion often have the diagnosis of epilepsy despite normal electroencephalograms (EEGs). To evaluate the proportion of patients referred to neurologists with presumed epilepsy and normal EEGs who have an alternative cause of syncope. It was a cross-sectional study of 55 consecutive patients aged 6-85 (41 +/- 24) years presenting with faints, falls, convulsions, and normal EEGs, who were referred to neurologists before going to cardiologists. All patients underwent clinical examination, electrocardiogram, and echocardiogram. Head-up tilt table testing (HUT), 24-hour-Holter, and carotid sinus massage was offered as needed. Electrophysiological studies were undertaken in patients with structural heart disease or severe palpitations. Anticonvulsant agents had been prescribed to 35 patients (64%) before entering the study. Vasovagal syncope was found in 22 (40%) patients, life-threatening arrhythmias in seven (13%), carotid sinus hypersensitivity in six (11%), orthostatic hypotension in three (5%), and aortic stenosis in one (2%). Etiology of syncope could not be found in 16 (29%) patients. Arrhythmias comprised two complete atrioventricular blocks, one sustained monomorphic ventricular tachycardia, one ventricular fibrillation, one atrial tachycardia, and two atrioventricular node reentrant tachycardias. Two patients developed a prolonged asystole during HUT. Presumptive diagnosis of syncope was found in 39 patients (71%). Patients on or off anticonvulsant drugs had 64% and 84% diagnosis of syncope, respectively (odds ratio = 0.33; 95% confidence interval 0.08-1.36; P = 0.13). Life-threatening arrhythmias and syncope can be present in patients with presumed epilepsy and normal EEG. Prescription of anticonvulsant agents in these patients should wait for a cardiovascular assessment.

Neuropsychological aspects of benign childhood epilepsy with centrotemporal spikes

Purpose To establish whether the disability in benign epilepsy with centrotemporal spikes (BECTS) is the result of the number of seizures, the anti-epileptic therapy or is an inherent characteristic of the syndrome itself. Methods Thirty-six children with BECTS were tested for cognitive functions prior to commencing treatment with anti-epileptic drugs, and the findings were compared with those in 15 children with normal electroencephalograms, performed for unrelated reasons. The data in the study group were further correlated with the laterality of the epileptic focus and the number of seizures. Results Scores for verbal functioning on neuropsychological tests were significantly lower in the study group than the control group. There was no relationship between the neuropsychological scores in the patients and either lateralization of the epileptic focus or number of seizures. Discussion Children with BECTS have an impaired ability to process verbal information. The deficiency is apparently a result of the pathological electrical discharges that are part of the syndrome and are not dependent on the epileptic focus laterality, the number of seizures, or the anti-epileptic treatment.

Thirteen-year follow-up of patients with tri-ortho-cresyl phosphate poisoning in northern suburbs of Xi’an in China

Based on reports published so far, organophosphorus (OP) compounds do remarkable harm to human health. In 1995 there was an outbreak of organophosphorus-ester induced delayed neuropathy (OPIDN) due to tri-ortho-cresyl phosphate (TOCP) poisoning in northern suburbs of Xi’an in China. The 74 affected patients were treated and followed up after definite diagnosis. 13 years later, all the epidemiological data obtained from 61 survivors were evaluated, and 15 patients underwent clinical, laboratory, neuroimaging and electrophysiological examinations. In addition, a review of the literature about the possible mechanism of OPIDN was made. According to our investigation, of 61 survivors, 35 patients almost regained normal function of limbs and work outside; 23 patients walked with bilateral support and could perform housework; and 3 patients could not self-care. The patients undergoing examinations presented spasticity and minor lower leg muscle atrophy without sensory impairment. Laboratory investigations and brain and spinal cord magnetic resonance imaging examinations were normal. Neurophysiological investigations also showed normal electroencephalogram and visual, brainstem auditory and somatosensory evoked potentials. Motor evoked potential (MEP) obtained from the upper limbs had normal central motor conduction time (CMCT). However, the CMCT of MEP response recorded from the bilateral lower limbs was delayed, or showed even no MEP responses. Motor and sensory nerve conduction velocity and electromyography studies were normal except for two severely affected patients. TOCP showed long-term effects on the nervous system and influenced the quality of life. OP compounds should be strictly regulated to prevent similar occurrences.

Brain Heterotopia

We present a case with intractable partial complex seizures in a 14-year-old girl who was found to have brain heterotopia on MRI and PET-CT. The patient presented with intractable partial complex seizures and a normal electroencephalogram. Her brain magnetic resonance imaging showed heterotopic gray matter lining the ventricular margin of the right occipital horn. Subsequent PET-CT demonstrated moderate tracer localization in the heterotopic gray matter surrounding the ventricular margin of the right occipital horn. Heterotopia may demonstrate normal or increased FDG uptake on PET, therefore its appearance may be deceiving when other pathologies are being considered.

The cardiac sodium channel mutation delQKP 1507-1509 is associated with the expanding phenotypic spectrum of LQT3, conduction disorder, dilated cardiomyopathy, and high incidence of youth sudden death

AimWe report diverse phenotypic consequences of the delQKP-1507–1509 cardiac sodium channel mutation in three generations of a Chinese family.Methods and resultsClinical and electrocardiographic (ECG), echocardiographic examination was followed by direct sequencing of SCN5A, KCNQ1, HERG, and LAMIN A/C to screen genomic DNA from blood samples. Of two mutation carriers, the proband was born with conduction disorders including second-degree atrioventricular (AV) block with prolonged QTc interval, additionally showing left anterior fascicular block (LAFB), incomplete right bundle-branch block (IRBBB), and intermittent third-degree AV block at 2 years, and clinical presentations of multiple syncope despite normal electroencephalograms at 8 years. Continuous ECG monitoring following presentation at 13 years revealed prolonged QTc and biphasic T-waves, multiple episodes of ventricular tachycardia, ventricular fibrillation, and torsades de pointes. Transthoracal echocardiography then revealed left ventricular dilatation and reduced systolic function. Another mutation carrier showed features of long QT syndrome type 3 (LQT3), LAFB, and dilated cardiomyopathy (DCM). Two additional subjects died suddenly at 13 and 33 years.ConclusionThis data compliments and expands the spectrum of phenotypes resulting from this known gain-of-function mutation, including not only LQT3, cardiac conduction defects, and sudden death but also DCM, hitherto associated with loss-of-function mutations, for the first time.

Altered calcium homeostasis in autism-spectrum disorders: evidence from biochemical and genetic studies of the mitochondrial aspartate/glutamate carrier AGC1

Autism is a severe developmental disorder, whose pathogenetic underpinnings are still largely unknown. Temporocortical gray matter from six matched patient-control pairs was used to perform post-mortem biochemical and genetic studies of the mitochondrial aspartate/glutamate carrier (AGC), which participates in the aspartate/malate reduced nicotinamide adenine dinucleotide shuttle and is physiologically activated by calcium (Ca(2+)). AGC transport rates were significantly higher in tissue homogenates from all six patients, including those with no history of seizures and with normal electroencephalograms prior to death. This increase was consistently blunted by the Ca(2+) chelator ethylene glycol tetraacetic acid; neocortical Ca(2+) levels were significantly higher in all six patients; no difference in AGC transport rates was found in isolated mitochondria from patients and controls following removal of the Ca(2+)-containing postmitochondrial supernatant. Expression of AGC1, the predominant AGC isoform in brain, and cytochrome c oxidase activity were both increased in autistic patients, indicating an activation of mitochondrial metabolism. Furthermore, oxidized mitochondrial proteins were markedly increased in four of the six patients. Variants of the AGC1-encoding SLC25A12 gene were neither correlated with AGC activation nor associated with autism-spectrum disorders in 309 simplex and 17 multiplex families, whereas some unaffected siblings may carry a protective gene variant. Therefore, excessive Ca(2+) levels are responsible for boosting AGC activity, mitochondrial metabolism and, to a more variable degree, oxidative stress in autistic brains. AGC and altered Ca(2+) homeostasis play a key interactive role in the cascade of signaling events leading to autism: their modulation could provide new preventive and therapeutic strategies.

Seizures in a 7-Month-Old Child After Exposure to the Essential Plant Oil Thuja

A previously healthy 7-month-old child was treated with homeopathic preparations of thuja, a potentially convulsant compound, for the purpose of providing a calming effect around times of immunizations. The child developed eight generalized tonic-clonic seizures with no other obvious cause, in the context of normal electroencephalograms and a normal brain magnetic resonance imaging scan. Seizures stopped after discontinuation of thuja and brief treatment with phenobarbital. The epileptogenic potential of plant-derived essential oils and other herbal remedies should be recognized by practitioners providing neurologic care to children.

Triggering sleep slow waves by transcranial magnetic stimulation

During much of sleep, cortical neurons undergo near-synchronous slow oscillation cycles in membrane potential, which give rise to the largest spontaneous waves observed in the normal electroencephalogram (EEG). Slow oscillations underlie characteristic features of the sleep EEG, such as slow waves and spindles. Here we show that, in sleeping subjects, slow waves and spindles can be triggered noninvasively and reliably by transcranial magnetic stimulation (TMS). With appropriate stimulation parameters, each TMS pulse at <1 Hz evokes an individual, high-amplitude slow wave that originates under the coil and spreads over the cortex. TMS triggering of slow waves reveals intrinsic bistability in thalamocortical networks during non-rapid eye movement sleep. Moreover, evoked slow waves lead to a deepening of sleep and to an increase in EEG slow-wave activity (0.5-4.5 Hz), which is thought to play a role in brain restoration and memory consolidation.

Incorrect Shunt Placement Due to Anatomic Variations of the Aortic Arch During Carotid Endarterectomy: A Rare Cause of Perioperative Ischemia?

To the Editor: Though shunt insertion limits interruption of blood flow during carotid thromboendarterectomy (CTEA), the procedure itself may provoke stroke, usually by air or plaque embolism (1). We report a previously undescribed potential cause of cerebral hypoperfusion during shunting: occlusion of the brachiocephalic trunk during left CTEA due to an anatomic aortic arch variation. A 71-yr-old woman underwent left CTEA under general anesthesia. Insertion of a right radial artery catheter was uneventful. After carotid artery cross-clamping and shunt insertion, we noted loss of the right radial pulse pressure. Her arterial blood pressure, assessed by an oscillometric blood pressure cuff placed on the left arm, remained unchanged. No compression or kinking of the catheter-tubing-transducer system was noticed, and fast-flushing did not show signs of under- or over-damping. Patch angioplasty was completed uneventfully, with normal electroencephalogram tracings. Immediately after shunt removal, her right arterial pressure regained its original shape and correlated with the values assessed by the cuff on the left arm. An anatomic variation of the aortic arch was suspected: subsequent postoperative magnetic resonance angiography confirmed the left common carotid emerging from the innominate trunk (Fig. 1). No postoperative neurological deficiency was noted.Figure 1.: MRA showing the left common carotid emerging from the brachiocephalic trunk. LCCA = left common carotid artery, BCT = brachiocephalic trunk, RCCA = right common carotid artery, RScA = right subclavian artery.Since up to 20% of patients present with aortic arch variation, unintentional occlusion of adjacent vessels and subsequent ischemia may occur during shunt procedures (2). Loss of radial pressure tracing demonstrated subobstruction of the right subclavian artery. We do not know whether the balloon was located in the subclavian artery or more proximal, in the brachiocephalic trunk. As no reflux of blood occurred in the operative field, occlusion of the brachiocephalic trunk seems more likely, potentially causing right cerebral hemisphere hypoperfusion in patients with inadequate redistribution of cerebral blood flow through the circle of Willis. To our knowledge, no case of stroke due to balloon obstruction of the opposite common carotid has been reported, and contralateral stroke remains exceptional. Indeed, during the North American Symptomatic Carotid Endarterectomy Trial (3), only one patient in 1415 awoke with a transient deficit in the contralateral carotid territory. Marc Koch, MD Marco Cristiani, MD Denis Schmartz, MD Department of Cardiothoracic and Vascular Anesthesiology Erasme University Hospital Free University of Brussels Brussels, Belgium [email protected]

Vasovagal syncope misdiagnosed as epilepsy for 17 years: prime importance of clinical history

ABSTRACT Distinguishing epilepsy from syncope often can be challenging. We report a case of a 20‐year‐old patient with presumed refractory epilepsy since the age of 3 years. Although the clinical suspicion of syncope was raised at the age of 9 years, key historic features were not identified, cardiac work‐up was not pursued and despite lack of electrographic evidence of epilepsy, he received anticonvulsant treatment. During his presurgical evaluation for “refractory epilepsy”, one typical event was captured that was associated with asystole and normal electroencephalogram. The diagnosis of vasodepressor syncope was made and anticonvulsant medication was discontinued. With this case report, we would like to emphasize the importance of a meticulous history and the need to perform continuous video electroencephalographic with simultaneous electrocardiographic recordings in the evaluation of paroxysmal events with atypical presentation. [Published with video sequences]

The Nonlinear Theory of Schizophrenia

Nonlinear properties exist within the brain across a hierarchy of scales and within a variety of critical neural processes. Only a few studies of brain activity in schizophrenia, however, have used nonlinear methods. This review paper evaluates the contribution of the nonlinear sciences towards understanding schizophrenia. Applications of nonlinear methods to the study of schizophrenia symptoms and to healthy and schizophrenia functional neuroscience data are reviewed. The main flaws of nonlinear algorithms and recent methods to correct these are also appraised. Initial research methods utilized in the study of nonlinearity in schizophrenia have fundamental methodological limitations. In the last decade, many of these problems have been addressed, facilitating future progress. Research incorporating these improvements has been applied to normal electroencephalogram (EEG) data and to the symptoms of schizophrenia, but not systematically to brain imaging data collected from patients with schizophrenia. There is strong statistical evidence for weak nonlinearity in normal EEG and in the fluctuations of the symptoms of schizophrenia. However, the contribution of nonlinear processes to brain dysfunction in schizophrenia is yet to be properly established or accurately quantified. Despite this, recent methodological advances suggest that a 'nonlinear theory' of schizophrenia may be helpful in understanding this disorder.

Analysis of the Bispectral Index During Natural Sleep in Children

The Bispectral Index (BIS) is a system used to measure sedation levels. Some investigators recently analyzed changes in the BIS during natural sleep in adults and found that the BIS diminished considerably as sleep became deeper. No such studies have been undertaken to investigate changes in the BIS in sleeping children. The aim of this work was to assess the trend of the BIS in the various stages of sleep in a group of children, performing a descriptive analysis on a limited number of cases. We evaluated 15 children with negative clinical findings and a normal electroencephalogram (EEG) as part of their follow-up for prior episodes of epilepsy, recording the BIS and EEG in a waking state, in the various stages of sleep and on reawaking. For each stage, the mean value, the standard deviation, and the range of BIS values were calculated. The results showed that the BIS decreased progressively as sleep became deeper. The correlation between the stage of sleep and the BIS was significant. On reawaking, a slow increase was apparent in the BIS.

Sickle cell disease: Ischemia and seizures

Although the prevalence of seizures in children with sickle cell disease (SCD) is 10 times that of the general population, there are few prospectively collected data on mechanism. With transcranial Doppler and magnetic resonance imaging (MRI) and angiography, we evaluated 76 patients with sickle cell disease, 29 asymptomatic and 47 with neurological complications (seizures, stroke, transient ischemic attack, learning difficulty, headaches, or abnormal transcranial Doppler), who also underwent bolus-tracking perfusion MRI. The six patients with recent seizures also had electroencephalography. Group comparisons (seizure, nonseizure, and asymptomatic) indicated that abnormal transcranial Doppler was more common in the seizure (4/6; 67%) and nonseizure (26/41; 63%) groups than in the asymptomatic (10/29; 34%) group (chi2; p = 0.045), but abnormal structural MRI (chi2; p = 0.7) or magnetic resonance angiography (chi2; p = 0.2) were not. Relative decreased cerebral perfusion was found in all seizure patients and in 16 of 32 of the remaining patients with successful perfusion MRI (p = 0.03). In the seizure patients, the perfusion abnormalities in five were ipsilateral to electroencephalographic abnormalities; one had normal electroencephalogram results. These findings suggest that vasculopathy and focal hypoperfusion may be factors in the development of sickle cell disease-associated seizures.

Case Study: Diagnosis of Insulinoma Using Continuous Glucose Monitoring System in a Patient With Diabetes

K.D., a 20-year-old white female college student was brought by her parents for evaluation of hypoglycemia. She had experienced multiple episodes of palpitations, blurred vision, and left facial paresthesias for a year, progressively worsening and occurring more frequently in the 2 months just before her appointment. Usually the episodes occurred between 3:00 and 7:30 p.m. The symptoms occurred without regard to meals and were relieved with food or juice. Her most severe witnessed episode, which occurred while she was at college, happened a few days before the consultation, while K.D. was working, 2 hours postprandially. Observers reported that she appeared confused, agitated, and diaphoretic. Her glucose via fingerstick by paramedics was 35 mg/dl. She received intravenous dextrose, and subsequently her glucose rose to 217 mg/dl with resolution of her symptoms. She had several episodes with neuroglycopenic symptoms and glucose levels of 35-45 mg/dl. There was no history indicating diabetic medications in her home. She also complained of a 25-lb weight gain during the past year. A year before her visit, K.D. was diagnosed with diabetes by oral glucose tolerance test (OGTT). The results were: View this table: At that time, she had a normal hemoglobin A1c, and she was instructed in diet and exercise. No antidiabetic medications had been prescribed. K.D. had a psychiatric evaluation, was diagnosed with depression, and was started on sertraline. In the month before the consultation, she also had a neurological work-up with negative computed tomography scans of the head and normal electroencephalogram. Her family history was significant only for diabetes of a maternal aunt. She denied allergies or use of cigarettes, alcohol, or illicit drugs. She was taking sertraline, 50 mg daily for the past year; ethinyl estradiol/norgestimate, one daily for the past 2 years; and oxcarbazepine, 175 mg twice daily for the …

Two Enigmatic Cases of Meningitis

Two Enigmatic Cases of Meningitis

Congenital varicella syndrome

The fetal consequences of chickenpox complicating pregnancy depends on the period of gestation at which the infection is contracted. The extremely rare classical form of congenital varicella syndrome, resulting from maternal varicella infection in the first trimester of pregnancy, is being reported here. The unusual features in this baby are bilateral hypoplastic lower extremities, fracture of bones, a normal electroencephalogram and phantom hernias of the anterior abdominal wall.

Estado epiléptico no convulsivo

Non-convulsive status epilepticus (NCSE) is an epileptic condition lasting more than 30 minutes in which continuous or recurrent seizure activity on the electroencephalogram (EEG) is responsible for diverse clinical symptoms including alteration of mental state, abnormal behaviour, perception disturbances or consciousness impairment. Most authors recognize two types of NCSE depending on the ictal electroencephalographic changes: generalized (absence status epilepticus) and complex partial status epilepticus (CPSE). In addition, there is also a simple form of partial status which is likely underdiagnosed because of its frequent progression to CPSE, subtle and varied symptomatology and high proportion of normal electroencephalograms (EEG). Absence status epilepticus (ASE) may occur in different clinical situations including idiopathic generalized epilepsy (typical AS), symptomatic generalized epilepsy (atypical AS), and elderly subjects without antecedents of epilepsy on chronic treatment with psychotropic drugs (de novo AS of late onset). Furthermore, CPSE is more frequent than previously mentioned. Although initially was equated with temporal lobe status epilepticus, extratemporal cases of CPSE have been well-documented, and the electroclinical characteristics of two types (I and II) of frontal CPSE have been recently described. NCSE may occur in patients with diverse clinical diagnosis such as hypoxic-anoxic encephalopathy, cancer, drugs, autoimmune disorders, Creutzfeldt-Jakob disease, chromosomal alterations, peritoneal dialysis, infections, cerebral hamartomas or head trauma. The identification of NCSE may be particularly arduous and, therefore, a high level of suspicion is essential to obtain an early diagnosis. An urgent EEG with administration of intravenous benzodiazepines is considered as the method of choice in the diagnostic evaluation of NCSE.

Remission of West syndrome associated with valproate hepatotoxicity

A 6-month-old girl developed West syndrome and it remitted in association with valproate-induced hepatic dysfunction. Plasma β-alanine elevated after valproate hepatotoxicity, which seemed to be a possible cause of remission. The patient has been seizure-free with normal electroencephalogram for 12 months without any anticonvulsants. Her developmental milestones were within normal limits at the age of 18 months.