An appraisal to Hans Berger by the time of his 150th birthday: the human EEG and tales of blood flow, heat and brain waves.

More than 100 years of research have passed by and still the human electroencephalogram (EEG) remains a puzzle to be solved. Starting from his studies on plethysmography until his theories on brain thermodynamics, Hans Berger was able to refine his method of recording cortical signs with the apparatus at his disposal in an ordinary neuropsychiatric yard towards an early account of human EEG. This review is an appraisal of his contribution to the field of modern neurophysiology.

Mais de 100 anos se passaram e o eletroencefalograma humano (EEG) continua sendo um enigma a ser desvendado. A partir de seus estudos sobre pletismografia até suas teorias sobre termodinâmica cerebral, Hans Berger conseguiu refinar seu método de registro da atividade elétrica cortical com os equipamentos a sua disposição em uma ala psiquiátrica comum produzindo uma descrição acurada do EEG humano. Esta revisão é um breve resumo de sua contribuição para o campo da neurofisiologia moderna.

An appraisal to Hans Berger by the time of his 150th birthday: the human EEG and tales of blood flow, heat and brain waves / Um ensaio sobre o aniversário de 150 anos de Hans Berger: uma história de sangue, calor e ondas cerebrais

Abstract More than 100 years of research have passed by and still the human electroencephalogram (EEG) remains a puzzle to be solved. Starting from his studies on plethysmography until his theories on brain thermodynamics, Hans Berger was able to refine his method of recording cortical signs with the apparatus at his disposal in an ordinary neuropsychiatric yard towards an early account of human EEG. This review is an appraisal of his contribution to the field of modern neurophysiology.

Resumo Mais de 100 anos se passaram e o eletroencefalograma humano (EEG) continua sendo um enigma a ser desvendado. A partir de seus estudos sobre pletismografia até suas teorias sobre termodinâmica cerebral, Hans Berger conseguiu refinar seu método de registro da atividade elétrica cortical com os equipamentos a sua disposição em uma ala psiquiátrica comum produzindo uma descrição acurada do EEG humano. Esta revisão é um breve resumo de sua contribuição para o campo da neurofisiologia moderna.

Clinical Neurophysiology of Zika Virus Encephalitis.

SUMMARY: Zika virus (ZIKV) has been shown to be highly neurotropic; neurologic disorders are a common complication of this infection. Encephalitis-an inflammation of the brain parenchyma associated with neurologic dysfunction-is a rare complication of ZIKV infections. It affects patients from young to elderly ages. Clinical presentation of ZIKV encephalitis may be heterogeneous, including altered mental status (decreased or altered level of consciousness, lethargy, or personality change), seizures, and focal deficits. Complementary diagnostic investigation should include neuroimaging, lumbar puncture, and EEG. Neuroimaging findings in ZIKV encephalitis are not specific and may be diverse, including normal findings, hyperintense lesions on MRI involving cortical or subcortical structures, symmetric or asymmetric lesions involving supra or infratentorial regions, and more widespread involvement such as brain swelling. A remarkable scarcity of neurophysiological data on ZIKV encephalitis was found in the literature. In line with other diagnostic examinations, there are no neurophysiological findings suggestive or specific of the disease. EEG in ZIKV encephalitis showed different results: normal or diffuse disorganization of background activity, asymmetry with abnormal focal slow waves, focal epileptic discharges or generalized spike-wave and multispike-wave complexes, and periods of generalized voltage attenuation.

Independent risk factors for seizures in critically ill patients on continuous EEG.

OBJECTIVE: The objective of this study was to characterize the independent risk factors for seizures in critically ill patients monitored with continuous EEG (cEEG). METHODS: We retrospectively investigated variables associated with cEEG seizures, first in the entire cohort of 156 patients and, subsequently, in the subgroup without seizures in the first 30 minutes of monitoring. RESULTS: Seizures were observed in 19.2% of recordings, and in 50% of these, seizures occurred in the first 30 minutes. In the entire cohort, epilepsy, acute seizures prior to cEEG, interictal epileptiform discharges (IEDs), lateralized periodic discharges (LPDs), and brief potentially ictal rhythmic discharges (BIRDs) were associated with a higher incidence of cEEG seizures, whereas coma, intravenous anaesthetic drugs, and generalized periodic discharges (GPDs) were associated with a lower incidence of seizures. On multivariate analysis, this association was maintained for acute seizures before cEEG (OR: 5.92) and IEDs (OR: 6.81). Excluding patients with seizures at the beginning of monitoring, acute seizures before cEEG, IEDs, LPDs, and BIRDs were associated with an increased risk of seizures. The presence of IEDs or LPDs in the first 30 minutes was associated with a 4.14-fold greater chance of seizures on cEEG. On multivariate analysis, acute seizures prior to recording (OR 7.29) and LPDs (OR: 5.38) remained associated with seizures on cEEG. Due to the sample size, BIRDs were not included in multivariate models. SIGNIFICANCE: Acute seizures prior to monitoring, IEDs, LPDs and BIRDs are important risk factors for cEEG seizures in critically ill patients.

Seizures in self-limited epilepsy with centrotemporal spikes: video-EEG documentation.

PURPOSE: Self-limited epilepsy with centrotemporal spikes, formerly called benign epilepsy with centrotemporal spikes, or rolandic epilepsy, is an age-related and well-defined epileptic syndrome. Since seizures associated with rolandic spikes are infrequent and usually occur during sleep, and repetitive or prolonged EEG recording for diagnostic purposes is not necessary for diagnosis, reports of ictal video-electroencephalographic seizures in this syndrome are rare. We aimed to show ictal video-EEG of typical rolandic seizures. METHODS: We report the ictal video-EEG recordings of two children with rolandic epilepsy who presented typical rolandic seizures during routine recording. RESULTS: Case 1: A 9-year-old boy, with normal development, had his first seizure at 8 years old, characterized by paresthesia in his left face, blocking of speech, and drooling. Carbamazepine was started with seizure control. Case 2: A 10-year-old boy, with normal development, started with focal seizures during sleep, characterized by eye and perioral deviation, and speech arrest at age of 7. He started using oxcarbazepine. Both patients underwent routine electroencephalography for electroclinical diagnosis and presented a seizure. CONCLUSION: Although self-limited epilepsy with centrotemporal spikes is a very common epileptic syndrome, seizure visualization is very difficult, and these videos may bring didactical information for recognition of this usual presentation of benign childhood focal epilepsy.

De Novo Myoclonic Status Epilepticus After Benzodiazepine Withdrawal.

Myoclonic status epilepticus (MSE) in patients without epilepsy, or de novo MSE, is a rare condition associated with several acute symptomatic etiologies, including drugs and toxins. We describe a 94-year-old woman with Alzheimer dementia and long use of mirtazapine 30 mg/d and alprazolam 1 mg/d who developed MSE approximately 24 hours after abrupt discontinuation of alprazolam. The patient was taking sulfamethoxazole/trimethoprim for urinary tract infection, diagnosed 2 weeks before admission. She had no history of seizures. Routine laboratory examinations were normal and head computed tomography showed no acute injuries. She received a loading dose of 1000 mg of intravenous valproate (VPA). Continuous electroencephalogram monitoring revealed very frequent generalized spikes and polyspikes in a markedly slowed background activity. Intravenous VPA 500 mg thrice a day and alprazolam 0.5 mg twice a day were prescribed, and antibiotic was switched to piperacillin/tazobactam. Myoclonic jerks ceased completely and electroencephalogram showed no epileptiform discharges 2 days after VPA treatment onset, with recovery of baseline neurological status. This is, to the best of our knowledge, the first report of de novo MSE related to abrupt discontinuation of benzodiazepines. Seizures and status epilepticus are potential adverse events after abrupt withdrawal of chronically used benzodiazepines, especially in conditions with intrinsic epileptogenic susceptibility, such as Alzheimer disease.

Outcomes of patients with altered level of consciousness and abnormal electroencephalogram: A retrospective cohort study.

INTRODUCTION: Nonconvulsive seizures (NCS) are frequent in hospitalized patients and may further aggravate injury in the already damaged brain, potentially worsening outcomes in encephalopathic patients. Therefore, both early seizure recognition and treatment have been advocated to prevent further neurological damage. OBJECTIVE: Evaluate the main EEG patterns seen in patients with impaired consciousness and address the effect of treatment with antiepileptic drugs (AEDs), continuous intravenous anesthetic drugs (IVADs), or the combination of both, on outcomes. METHODS: This was a single center retrospective cohort study conducted in a private, tertiary care hospital. Consecutive adult patients with altered consciousness submitted to a routine EEG between January 2008 and February 2011 were included in this study. Based on EEG pattern, patients were assigned to one of three groups: Group Interictal Patterns (IP; EEG showing only interictal epileptiform discharges or triphasic waves), Group Rhythmic and Periodic Patterns (RPP; at least one EEG with rhythmic or periodic patterns), and Group Ictal (Ictal; at least one EEG showing ictal pattern). Groups were compared in terms of administered antiepileptic treatment and frequency of unfavorable outcomes (modified Rankin scale ≥3 and in-hospital mortality). RESULTS: Two hundred and six patients (475 EEGs) were included in this analysis. Interictal pattern was observed in 35.4% (73/206) of patients, RPP in 53.4% (110/206) and ictal in 11.2% (23/206) of patients. Treatment with AEDs, IVADs or a combination of both was administered in half of the patients. While all Ictal group patients received treatment (AEDs or IVADs), only 24/73 (32.9%) IP group patients and 55/108 (50.9%) RPP group patients were treated (p<0.001). Hospital length of stay (LOS) and frequency of unfavorable outcomes did not differ among the groups. In-hospital mortality was higher in IVADs treated RPP patients compared to AEDs treated RPP patients [11/19 (57.9%) vs. 11/36 (30.6%) patients, respectively, p = 0.049]. Hospital LOS, in-hospital mortality and frequency of unfavorable outcomes did not differ between Ictal patients treated exclusively with AEDs or IVADs. CONCLUSION: In patients with acute altered consciousness and abnormal routine EEG, antiepileptic treatment did not improve outcomes regardless of the presence of periodic, rhythmic or ictal EEG patterns.

Magnetic fields in noninvasive brain stimulation.

The idea that magnetic fields could be used therapeutically arose 2000 years ago. These therapeutic possibilities were expanded after the discovery of electromagnetic induction by the Englishman Michael Faraday and the American Joseph Henry. In 1896, Arsène d'Arsonval reported his experience with noninvasive brain magnetic stimulation to the scientific French community. In the second half of the 20th century, changing magnetic fields emerged as a noninvasive tool to study the nervous system and to modulate neural function. In 1985, Barker, Jalinous, and Freeston presented transcranial magnetic stimulation, a relatively focal and painless technique. Transcranial magnetic stimulation has been proposed as a clinical neurophysiology tool and as a potential adjuvant treatment for psychiatric and neurologic conditions. This article aims to contextualize the progress of use of magnetic fields in the history of neuroscience and medical sciences, until 1985.

Gastaut type idiopathic childhood occipital epilepsy.

Gastaut type idiopathic childhood occipital epilepsy is an uncommon epileptic syndrome characterised by frequent seizures, most commonly presenting as elementary visual hallucinations or blindness. Other occipital (non-visual) symptoms may also occur. Interictal EEG typically shows occipital paroxysms, often with fixation-off sensitivity. Ictal EEG is usually characterised by interruption by paroxysms and sudden appearance of low-voltage, occipital, fast rhythm and/or spikes. Despite well described clinical and EEG patterns, to our knowledge, there are very few reports in the literature with video-EEG recording of either seizure semiology or fixation-off phenomena. We present a video-EEG recording of a 12-year-old girl with Gastaut type epilepsy, illustrating the interictal and ictal aspects of this syndrome. Our aim was to demonstrate the clinical and neurophysiological pattern of a typical seizure of Gastaut type epilepsy, as well as the fixation-off phenomena, in order to further clarify the typical presentation of this syndrome. [Published with video sequences].

Corpus callosotomy in a patient with startle epilepsy.

Startle epilepsy is a syndrome of reflex epilepsy in which the seizures are precipitated by a sudden and surprising, usually auditory, stimulus. We describe herein a girl who had been suffering with startle-induced seizures since 2 years of age. She had focal, tonic and tonic-clonic seizures, refractory to antiepileptic treatment. Daily tonic seizures led to very frequent falls and morbidity. Neurologically, she had no deficit. Interictal EEG showed slow waves and epileptiform discharges in central and fronto-central regions. Video-polygraphic recordings of seizures, triggered by stimuli, showed generalised symmetric tonic posturing with ictal EEG, characterised by an abrupt and diffuse electrodecremental pattern of fast activity, followed by alpha-theta rhythm superimposed by epileptic discharges predominantly over the vertex and anterior regions. Magnetic resonance imaging showed no abnormalities. Corpus callosotomy was performed when the patient was 17. Since surgery, the patient (one year follow-up) has remained seizure-free. Corpus callosotomy may be considered in patients with startle epilepsy and tonic seizures, in the absence of focal lesions amenable to surgery. [Published with video sequences].

Does the patient's hand hold the key to preventing secondary generalization in mesial temporal lobe epilepsy?

This study aimed to analyze the impact of ictal dystonic posturing (DP) in postoperative seizure outcome and to assess the influence of DP in generalized tonic-clonic seizure (GTCS) occurrence during video-EEG monitoring of patients with temporal lobe epilepsy with mesial temporal sclerosis. The impact of DP on surgical outcome remains controversial. Moreover, DP has been recently associated with brain networks avoiding GTCS occurrence. Five hundred twenty-seven seizures of 171 patients who were submitted to standard anterior temporal lobectomy (ATL) between 2002 and 2010, with at least one year of post-surgical follow-up, were retrospectively analyzed and classified as with or without DP and as evolving or not to GTCS. The ictal semiologic correlates of DP, timing elapsed since precedent seizure and antiepileptic drug (AED) intake before each seizure were evaluated. Seizure outcome after ATL was assessed according to Engel's scale. Fifty-eight out of 171 patients (34%) exhibited ictal DP, of which 91.5% were always unilateral and contralateral to the operated side. DP was related to shorter seizures (p=0.007) and a much lower likelihood of the seizure evolving to GTCS (p=0.001), even during AED withdrawal (p=0.002). There was no association between DP and prognosis regarding seizure control as the result of the surgical resection, either in patients with shorter or in those with longer period of follow-up. Our data support the hypothesis that DP reflects a brain network activation that helps avoid GTCS, even during AED withdrawal.

[Post-operative progress of patients with Rasmussen's encephalitis who have undergone hemispherotomy surgery]. / Evolucion posquirurgica en pacientes con encefalitis de Rasmussen operados por hemisferotomia.

INTRODUCTION: Rasmussen's encephalitis (RE) is a progressive pathology affecting the brain that causes unilateral hemispheric atrophy, neurological dysfunction and refractory epilepsy. Hemispherotomy is considered the most effective treatment today, but some cases present certain peculiarities that can seriously affect the decision to go ahead with this procedure. AIMS: To evaluate the post-operative progress made by children with RE who have undergone hemispherotomy surgery, and who, in the pre-operative assessment, presented certain characteristics that complicated the decision to perform surgery. PATIENTS AND METHODS: The sample selected for study consisted of the cases of RE attended in the Hospital Sao Paulo between 2003 and 2012 who, in the pre-surgery evaluation, presented clinical, electroencephalographic or neuroimaging evidence of involvement of both brain hemispheres, compromise of the dominant brain hemisphere, absence of severe neurological deficit and absence of criteria for refractory epilepsy and atypical crises. The post-operative assessment of the epileptic seizures was evaluated using the Engel scale; motor function was analysed with the Gross Motor Function Classification System and Manual Ability Classification System scales, and language was evaluated clinically. RESULTS: Six cases were selected (four girls), with a mean age at clinical onset of 3.3 ± 1.2 years (range: 2-7 years) and a mean age at hemispherotomy of 6.7 years (range: 2.3-16.5 years). The mean post-surgery follow-up time was three years (range: 0.5-7.2 years). In the post-surgery evaluation of the epileptic seizures, four cases were classified as Engel class I (66%); there was some improvement in motor functioning in five of them, and language improved in all cases. CONCLUSIONS: Hemispherotomy must be considered an efficient option for treatment in children with RE.

Granule cell dispersion is not a predictor of surgical outcome in temporal lobe epilepsy with mesial temporal sclerosis.

The aim of this retrospective study of a series of patients with mesial temporal lobe epilepsy (MTLE) and mesial temporal sclerosis (MTS) was to analyze the association of granule cell dispersion (GCD) with surgical prognosis, patterns of MTS and clinical data. Hippocampal specimens from 66 patients with MTLE and unilateral MTS and from 13 controls were studied. Quantitative neuropathological evaluation was performed on NeuN-stained hippocampal sections. Patients' clinical data, types of MTS and surgical outcome were reviewed. GCD occurred in 45.5% of cases and was not correlated with clinical variable. More severe neuronal loss was observed in patients with GCD. Except for MTS Type 2 - observed only in four no- GCD patients - groups did not differ with respect to the types of MTS. Surgical outcome was similar in both groups. In conclusion, GCD was associated with the degree of hippocampal cell loss, but was not a predictor of surgical outcome.

Morphological variations of hippocampal formation in epilepsy: image, clinical and electrophysiological data.

Morphological variations of hippocampal formation (MVHF) are observed in patients with epilepsy but also in asymptomatic individuals. The precise role of these findings in epilepsy is not yet fully understood. This study analyzes the hippocampal formation (HF) morphology of asymptomatic individuals (n = 30) and of patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) (n = 68), patients with malformations of cortical development (MCD) (n = 34), or patients with pure morphological variations of hippocampal formation (pure MVHF) (n = 12). Main clinical and electrophysiological data of patients with MVHF were also analyzed. Morphological variations of hippocampal formation are more frequently observed in patients with MCD than in patients with MTLE-HS or in asymptomatic individuals. Patients with pure morphological variations of hippocampal formation showed higher incidence of extratemporal seizure onset. Refractoriness seems to be more associated with other abnormalities, like HS or MCD, than with the HF variation itself. Thus, although morphological HF abnormalities might play a role in epileptogenicity, they seem to contribute less to refractoriness.

Surgical and postmortem pathology studies: contribution for the investigation of temporal lobe epilepsy / Patologia cirúrgica e post mortem: contribuição para a investigação da epilepsia do lobo temporal

Pathology studies in epilepsy patients bring useful information for comprehending the physiopathology of various forms of epilepsy, as well as aspects related to response to treatment and long-term prognosis. These studies are usually restricted to surgical specimens obtained from patients with refractory focal epilepsies. Therefore, most of them pertain to temporal lobe epilepsy (TLE) with mesial temporal sclerosis (MTS) and malformations of cortical development (MCD), thus providing information of a selected group of patients and restricted regions of the brain. Postmortem whole brain studies are rarely performed in epilepsy patients, however they may provide extensive information on brain pathology, allowing the analysis of areas beyond the putative epileptogenic zone. In this article, we reviewed pathology studies performed in epilepsy patients with emphasis on neuropathological findings in TLE with MTS and MCD. Furthermore, we reviewed data from postmortem studies and discussed the importance of performing these studies in epilepsy populations.

Estudos de patologia em pacientes com epilepsia trazem informações úteis para compreender a fisiopatologia de várias formas de epilepsia, bem como aspectos relacionados ao tratamento e ao prognóstico a longo prazo. Esses estudos são usualmente restritos a espécimes cirúrgicos obtidos de pacientes com epilepsias focais refratárias. Portanto, a maioria diz respeito à epilepsia do lobo temporal (ELT) com esclerose mesial temporal (EMT) e às malformações do desenvolvimento cortical (MDC). Desse modo, fornecem informações sobre um grupo selecionado de pacientes e sobre regiões restritas do cérebro. Raramente são realizados estudos post mortem do cérebro inteiro em pacientes com epilepsia; entretanto, eles podem prover informações relevantes sobre patologia cerebral, permitindo a análise de áreas além da zona epileptogênica putativa. Neste artigo, foram revisados estudos de patologia feitos em pacientes com epilepsia, com ênfase nos achados neuropatológicos em ELT com EMT e MDC. Foram revisados, ainda, dados de estudos post mortem e discutiu-se a importância da realização desses estudos em populações de pessoas com epilepsia.

Granule cell dispersion is associated with memory impairment in right mesial temporal lobe epilepsy.

PURPOSE: We analyzed the association of granule cell dispersion (GCD) with memory performance, clinical data and surgical outcome in a series of patients with mesial temporal lobe epilepsy (MTLE) and mesial temporal sclerosis (MTS). METHOD: Hippocampal specimens from 54 patients with MTLE (27 patients with right MTLE and 27 with left MTLE) and unilateral MTS, who were separated into GCD and no-GCD groups and thirteen controls were studied. Quantitative neuropathological evaluation was performed using hippocampal sections stained with NeuN. Patients' neuropsychological measures, clinical data, type of MTS and surgical outcome were reviewed. RESULTS: GCD occurred in 28 (51.9%) patients. No correlation between GCD and MTS pattern, clinical data or surgical outcome was found. The presence of GCD was correlated with worse visuospatial memory performance in right MTLE, but not with memory performance in left MTLE. CONCLUSION: GCD may be related to memory impairment in right MTLE-MTS patients. However, the role of GCD in memory function is not precisely defined.

Major depressive disorder as a predictor of a worse seizure outcome one year after surgery in patients with temporal lobe epilepsy and mesial temporal sclerosis.

PURPOSE: The association between pre-surgical psychiatric disorders (PDs) and worse seizure outcome in patients with refractory epilepsy submitted to surgery has been increasingly recognized in the literature. The present study aimed to verify the impact of pre- and post-surgical PD on seizure outcome in a series of patients with refractory temporal lobe epilepsy and mesial temporal sclerosis (TLE-MTS). METHOD: Data from 115 TLE-MTS patients (65 females; 56.5%) who underwent cortico-amygdalohippocampectomy (CAH) were analyzed. Pre- and post-surgical psychiatric evaluations were performed using DSM-IV and ILAE criteria. The outcome subcategory Engel IA was considered as corresponding to a favorable prognosis. A multivariate logistic regression model was applied to identify possible risk factors associated with a worse seizure outcome. RESULTS: Pre-surgical PDs, particularly major depressive disorder (MDD), anxiety and psychotic disorders, were common, being found in 47 patients (40.8%). Fifty-six patients (48.7%) were classified as having achieved an Engel IA one year after CAH. According to the logistic regression model, the presence of pre-surgical MDD (OR=5.23; p=0.003) appeared as the most important risk factor associated with a non-favorable seizure outcome. CONCLUSION: Although epilepsy surgery may be the best treatment option for patients with refractory TLE-MTS, our findings emphasize the importance of performing a detailed psychiatric examination as part of the pre-surgical evaluation protocol.

Pre-surgical predictors for psychiatric disorders following epilepsy surgery in patients with refractory temporal lobe epilepsy and mesial temporal sclerosis.

Psychiatric outcomes of patients submitted to epilepsy surgery have gained particular interest given the high prevalence of pre-surgical psychiatric disorders (PD) in this population. The present study aimed to verify the possible pre-surgical predictors for psychiatric disorders following epilepsy surgery in a homogeneous series of patients with refractory temporal lobe epilepsy and mesial temporal sclerosis (TLE-MTS). Data from 115 TLE-MTS patients (65 females; 56.5%) who underwent cortico-amygdalohippocampectomy were included. Pre- and post-surgical psychiatric evaluations were performed using DSM-IV criteria. Pre-surgical PD - particularly mood, anxiety and psychotic disorders - were diagnosed in 47 patients (40.8%). Twenty-seven patients (54% of those with pre-surgical PD) demonstrated a remission of psychiatric symptoms on post-surgical psychiatric evaluation. Eleven patients (9.6%) developed de novo PD. The presence of pre-surgical depression (OR=3.32; p=0.008), pre-surgical interictal psychosis (OR=4.39; p=0.009) and epileptiform discharges contralateral to the epileptogenic zone (OR=2.73; p=0.01) were risk factors associated with post-surgical PD. Although epilepsy surgery is considered to be the best treatment option for patients with refractory TLE-MTS, the relatively high psychiatric comorbidities observed in surgical candidates and their possible negative impact on post-surgical outcomes require a careful pre-surgical evaluation of clinical, sociodemographic and psychiatric factors.