A new strategy for treating drug-resistant focal aware seizures: thalamic specific nuclei deep brain stimulation. Illustrative case.

BACKGROUND: Focal aware seizures (FASs) are relatively common and frequently pharmaco-resistant. If the seizure onset zone (SOZ) is in eloquent cortical areas, making resective surgery risky and inadvisable, deep brain stimulation (DBS) of the anterior nucleus of the thalamus, which is efficacious in less than half of the cases, has been the main alternative. New targets should be searched to address this deficiency. The present study aims to determine if DBS of different thalamic specific nuclei can modulate the abnormal electrical activity of the SOZ located in their respective cortical projection areas. Herein, the authors present the first patient in an ongoing trial. OBSERVATIONS: A 60-year-old female patient presented with 25-year history of pharmaco-resistant focal aware visual seizures frequently evolving to focal impaired awareness seizures. The SOZ was in the right occipital lobe (positron emission tomography-computed tomography/video electroencephalography). Magnetic resonance imaging was normal. She underwent ipsilateral lateral geniculate nucleus (LGN) DBS procedure. After a 24-month follow-up, seizure frequency decreased by 97%, improving quality of life and daily functioning without complications. LESSONS: This is the first time the LGN has been targeted in humans. The results support the hypothesis that led to this study. This strategy represents a paradigm shift in the way of treating pharmaco-resistant FASs not amenable to resective surgery.

The impact of subcaudate tractotomy on delusions and hallucinations in psychotic patients.

BACKGROUND: Delusions and hallucinations, hallmarks of the psychotic disorders, usually do not respond to surgical intervention. For many years, the surgical technique of choice for the treatment of refractory aggressiveness in psychotic patients in our Service was amygdalotomy in isolation or associated with anterior cingulotomy. No improvement of hallucinations and delusions was noticed in any of these patients. To improve the control of aggression, subcaudate tractotomy was added to the previous surgical protocol. The main goal of the present study was to investigate the impact of this modified surgical approach on delusions and hallucinations. METHODS: Retrospective analysis of the medical records of psychotic patients presenting with treatment-resistant aggressiveness, delusions, and hallucinations submitted to bilateral subcaudate tractotomy + bilateral anterior cingulotomy + bilateral amygdalotomy in our institution. RESULTS: Five patients, all males, with ages ranging from 25 to 65 years, followed up by a mean of 45.6 months (17-72 months), fulfilled the inclusion criteria. Delusions and hallucinations were abolished in four of them. CONCLUSION: These results suggest that the key element for relieving these symptoms was the subcaudate tractotomy and that the orbitofrontal and ventromedial prefrontal cortices play an important role in the genesis of hallucinatory and delusional symptoms of schizophrenia and other psychoses.

A new method for intraoperative localization of epilepsy focus by means of a gamma probe / Um novo método para a localização intraoperatória de foco de epilepsia mediante utilização de gamaprobe

Objective To evaluate the utility of a new multimodal image-guided intervention technique to detect epileptogenic areas with a gamma probe as compared with intraoperative electrocorticography. Materials and Methods Two symptomatic patients with refractory epilepsy underwent magnetic resonance imaging, videoelectroencephalography, brain SPECT scan, neuropsychological evaluation and were submitted to gamma probe-assisted surgery. Results In patient 1, maximum radioactive count was initially observed on the temporal gyrus at about 3.5 cm posteriorly to the tip of the left temporal lobe. After corticotomy, the gamma probe indicated maximum count at the head of the hippocampus, in agreement with the findings of intraoperative electrocorticography. In patient 2, maximum count was observed in the occipital region at the transition between the temporal and parietal lobes (right hemisphere). During the surgery, the area of epileptogenic activity mapped at electrocorticography was also delimited, demarcated, and compared with the gamma probe findings. After lesionectomy, new radioactive counts were performed both in the patients and on the surgical specimens (ex-vivo). Conclusion The comparison between intraoperative electrocorticography and gamma probe-assisted surgery showed similarity of both methods. The advantages of gamma probe include: noninvasiveness, low cost and capacity to demonstrate decrease in the radioactive activity at the site of excision after lesionectomy. .

Objetivo Avaliar a utilidade de um novo método de intervenção multimodal guiado por imagem, permitindo a detecção de áreas epileptogênicas mediante utilização de gamaprobe em comparação à eletrocorticografia intraoperatória. Materiais e Métodos Dois pacientes sintomáticos com epilepsia refratária realizaram ressonância magnética, videoeletroencefalograma, SPECT cerebral, avaliação neuropsicológica e foram submetidos a neurocirurgia usando gamaprobe. Resultados No paciente 1 as contagens radioativas inicialmente estavam no máximo no giro temporal, cerca de 3,5 cm posterior à ponta do lobo temporal esquerdo. Após corticotomia, o gamaprobe apontou o ponto máximo na cabeça do hipocampo, de acordo com os achados de eletrocorticografia intraoperatória. No paciente 2 as contagens foram máximas na região occipital em sua transição com os lobos temporal e parietal (hemisfério direito). Na cirurgia, a área mapeada da atividade epileptogênica na eletrocorticografia foi também delimitada, demarcada e comparada aos dados do gamaprobe. Após a lesionectomia, procedeu-se uma nova radiocontagem no paciente e na peça cirúrgica (ex-vivo). Conclusão A comparação entre os métodos mostrou acurácia praticamente similar. As vantagens do gamaprobe foram a de não ser invasivo, ser de baixo custo e também ser relevante para mostrar a redução da atividade radioativa no local da exérese. .

Striatal somatotopy and motor responses evoked by acute electrical stimulation of the posterior striatum in rats.

INTRODUCTION/OBJECTIVES: Previous experiments suggest that the striatal sensorimotor territory in rats is located in its dorsolateral region, along the rostrocaudal axis, unlike what has been observed in primates. In the present study, electrical stimulation was performed to investigate the degree of participation of the posterior striatum in its motor territory, its somatotopic organization, and the motor responses evoked by stimulation. METHODS: Twenty-five rats were submitted to stereotactic stimulation of the posterior striatum under general anesthesia, receiving consecutively four different current intensities. The motor responses observed in the different body parts were registered for later comparison. We considered as threshold the smallest of these current intensities able to evoke a motor response. RESULTS: The observed motor responses were qualitatively different for each segment: forepaws: ipsilateral, adduction, and contralateral abduction; hindpaws: ipsilateral, flexion, and contralateral, extension/abduction; trunk, rotation/flexion; and tail, rotation/elevation. High-frequency, small-amplitude distal tremor occurred in the ipsilateral forepaw in 95% of the animals. Progressively larger current intensities were necessary for the induction of motor response in the forepaws, hindpaws, and trunk/tail, in that order. CONCLUSIONS: The results allowed us to infer the following posterior striatal somatotopic organization: forepaws, posterolaterally, being the contralateral medial to the ipsilateral; trunk/tail, anteromedially; and hindpaws, in an intermediate position, being the contralateral posterior to the ipsilateral. It is suggested that the tremor and the other observed motor responses derive from the excitation of striatal projection neurons and that the striatum may play an important role in the genesis of essential tremor.

Possible mechanisms involved in subthalamotomy-induced dyskinesia in patients with Parkinson's disease.

BACKGROUND/AIMS: Operation-induced dyskinesia (OID) occurs in approximately 10% of patients submitted to subthalamotomy. The goal of the authors was to determine the possible causes of this feared complication. METHODS: The 54 patients who underwent unilateral subthalamotomy were divided into two groups: the OID group (OIDG), composed of 6 patients who developed dyskinesia following the operation, and the control group (CG), consisting of 48 patients who did not present this complication. The two groups were compared regarding age; sex; presence of levodopa-induced dyskinesia (LID) and/or stimulation-induced dyskinesia (SID); side of the operation; territories of the subthalamic nucleus (STN) involved by the lesion, and degree of lesion extension towards the zona incerta (ZI). RESULTS: The lesion involved the dorsolateral territory of the STN and was almost completely restricted to this nucleus in all patients of the OIDG, while it spread to the ZI in all but 1 patient of the CG. SID was significantly (p < 0.05) more frequent in the OIDG. There was also a strong trend favoring LID (p = 0.055). CONCLUSIONS: Damage to the dorsolateral territory of the STN and sparing of the ZI seem to be essential for the development of OID. SID and, to a lesser extent, LID are apparently significant risk factors for the development of this complication.

Effects of unilateral stereotactic posterior striatotomy on harmaline-induced tremor in rats.

Although long known and the most prevalent movement disorder, pathophysiology of essential tremor (ET) remains controversial. The most accepted hypothesis is that it is caused by a dysfunction of the olivocerebellar system. Vilela Filho et al. [2001; Stereotact Funct Neurosurg 77:149-150], however, reported a patient with unilateral hand ET that was completely relieved after a stroke restricted to the contralateral posterior putamen and suggested that ET could be the clinical manifestation of posterior putamen hyperactivity. The present study was designed to evaluate this hypothesis in the most often used model of ET, harmaline-induced tremor in rats. Fifty-four male Wistar rats were randomly distributed into three groups: experimental (EG), surgical control (SCG), and pharmacological control (PCG) groups. EG animals underwent stereotactic unilateral posterior striatotomy. SCG rats underwent sham lesion at the same target. PCG served exclusively as controls for harmaline effects. All animals received, postoperatively, intraperitoneal harmaline, and the induced tremor was video-recorded for later evaluation by a blind observer. Thirteen animals were excluded from the study. Limb tremor was reduced ipsilaterally to the operation in 20 of 21 rats of EG and in two of nine of SCG, being asymmetric in one of 10 of PCG rats. Comparisons between EG × SCG and EG × PCG were statistically significant, but not between SCG × PCG. Limb tremor reduction was greater in anterior than in posterior paws. Lateral lesions yielded better results than medial lesions. These results suggest that the posterior striatum is involved with harmaline-induced tremor in rats and support the hypothesis presented.

Vagus nerve stimulator in patients with epilepsy: indications and recommendations for use.

Epilepsy comprises a set of neurologic and systemic disorders characterized by recurrent spontaneous seizures, and is the most frequent chronic neurologic disorder. In patients with medically refractory epilepsy, therapeutic options are limited to ablative brain surgery, trials of experimental antiepileptic drugs, or palliative surgery. Vagal nerve stimulation is an available palliative procedure of which the mechanism of action is not understood, but with established efficacy for medically refractory epilepsy and low incidence of side-effects. In this paper we discuss the recommendations for VNS use as suggested by the Brazilian League of Epilepsy and the Scientific Department of Epilepsy of the Brazilian Academy of Neurology Committee of Neuromodulation.

Mielinólise pontina e extra-pontina associada a Shoshin beribéri em paciente etilista / Central pontine and extra-pontine myelinosis in alcoholic patient with Shoshin beriberi

A mielinólise pontina está classicamente associada à rápida correção de hiponatremia crônica. Recentemente, fatores importantes adicionais tem sido descritos na patogênese dessa condição. Relatamos o caso de um paciente de 43 anos, etilista, desnutrido, que apresentou quadro agudo de insuficiência cardíaca por "Shoshin beribéri", insuficiência renal com tratamento por diálise. Evoluiu com tetraparesia e coma. Apresentou mielinólise pontina central e extra-pontina à ressonância magnética de crânio e anormalidades no potencial evocado auditivo.

[Central pontine and extra-pontine myelinosis in alcoholic patient with Shoshin beriberi]. / Mielinólise pontina e extra-pontina associada a Shoshin beribéri em paciente etilista.

The central pontine myelinosis is classically related with rapid correction of chronic hyponatremia. Recently, important additional factors have been described in the pathogenesis of this condition. We report the case of a 43-year-old alcoholic malnourished man, with acute renal failure with dialytic treatment, and output failure Shoshin beriberi. He had tetraplegy and coma. Confirmation of pontine and extrapontine myelinosis by magnetic resonance imaging, and abnormalities on auditive evoked potentials are described.

Potenciais evocados auditivos de curta latência: registro com eletrodos de foramem oval / Intracranial brainstem auditory evoked potentials with Foramen Ovale Electrodes

O registro dos Potenciais Evocados Auditivos de Tronco Cerebral, com eletrodos intracranianos crônicos, próximos ao tronco cerebral, é possível com o uso de Eletrodos de Foramem Oval. Dez pacientes com epilepsia temporal crônica, candidatos a tratamento cirúrgico, foram submetidos a implantes de Eletrodos de Foramem Oval, com múltiplos contatos, para a investigaçäo de atividade epileptiforme. Estes pacientes submeteram-se ao registro de Potenciais Evocados Auditivos, simultaneamente, com eletrodos de escalpo e através dos contatos dos Eletrodos de Foramem Oval. A localizaçä dos contatos intracranianos foi realizada através de Tomografia Computadorizada Craniana. As latência absolutas para as ondas I a V, os intervalos inter-picos, bem como as amplitudes das ondas I e V, registrados intracranialmente, mostraram-se comparóveis aos valores obtidos no escalpo. O registro de componentes subcorticais dos potenciais auditivos, através de Eletrodos de Foramem Oval, parece ser um método promissor para a monitorizaçäo trans-cirúrgica em neurologia e otologia

Investigaçäo pré-operatória de epilepsias de lobo temporal com eletrodos de forame oval / Pre operative investigation of temporal lobe epilepsy with foramen ovale eletrodes (FOE)

Quinze pacientes com epilepsia do lobo temporal foram investigados com eletrodos de forame oval(EFO). A indicaçäo da implantaçäo desses eletrodos foi por incapacidade de registros de superfície/esfenoidais de permitir lateralizaçäo do início das crises ou por incongruência entre início ictal e achados de neuroimagem. Dos quinze pacientes, quatro apresentavam ressecçäo temporal prévia, um apresentava uma lesäo e os dez restantes tiveram os registros de superfície e com EFO comparados neste estudo. Nesses dez pacientes foi possível lateralizar o início de 82 (por cento) das crises com os EFO, em contraste com um índice de 33 (por cento) com eletrodos de superfície e esfenoidais (p<0,001). O lado envolvido no início das crises correlacionou com maior atrofia das estruturas mesiais, conforme a análise qualitativa do exame de ressonância magnética. Como complicaçäo grave houve um caso de meningite séptica. Dois pacientes tiveram parestesia facial transitória e um apresentou também paresia reversível do VI nervo craniano. O uso dos EFO para registro de crises em pacientes selecionados permite lateralizaçäo confiável do início das crises, com qualidade superior ao registro com eletrodos de superfície e esfenoidais e custo e complexidade inferiores à investigaçäo com eletrodos de profundidade e placas subdurais crônicas

Centros de cirurgia de epilepsia: ponto de vista (1) / Epilepsy surgery center: point of view (1)

O autor relata a história da cirurgia da epilepsia quando teve início sua prática sistemática no Instituto de Neurologia de Montreal, há cinquenta anos atrás até os dias atuais, traçando um paralelo entre as condiçöes de trabalho dos grupos de cirurgia da epilepsia nos Estados Unidos e Canadá com os do Brasil e expöe o seu ponto de vista sobre as perspectivas da cirurgia da epilepsia no Brasil

Síndrome de desconexäo inter-hemisférica após calosotomia total associada a comissurotomia anterior para tratamento de epilepsia resistente: relato de um caso / Interhemispheric disconnection syndrome following total callosotomy associated with anterior commissurotomy for the treatment of intractable epilepsy: report of a case

Os autores fazem breve abordagem das indicaçöes da calosotomia para tratamento de crises resitentes e relatam um caso em que ocorreu síndrome de desconexäo inter-hemisférica clássica, após calosotomia total associada a comissurotomia anterior. A síndrome de desconexäo foi mais severa nos primeiros 5 dias de pós-operatório, com boa melhroa após o 11§ dia, ocorrendo recuperaçäo funcional quase completa e, também, reduçäo significativa da freqüência das crises

Neuropatia motora hereditária distal tipo 1: estudo de uma familia / Inherited motor neuropathy distal type 1: study on a family

Este trabalho descreve o estudo de uma família portadora de neuropatia motora hereditária distal tipo I (harding 1.984): 5 membros acometidos em 3 geraçöes foram examinados, evidenciando herança autossômica, início anterior aos 15 anos de idade, o membro mais velho anda e tem 63 anos de idade. A concordância intrafamiliar é alta e a avaliaçäo neurofisiológica foi decisiva para o diagnóstico, evidenciando velocidades de conduçäo neural e amplitude de potenciais sensitivos normais, ao lado de sinais de desnervaçäo e motora

Comparaçäo entre distribuiçäo de campo e campo máximo de potencial entre os eletrodos zigomáticos anteriores e posteriores, em epilepsia do lobo temporal / Comparison on distribution of field and maximal field potential between the anterior and posterior zygomatic elements, in temporal lobe epilepsy

10 pacientes portadores de epilepsia do lobo temporal foram submetidas a registros eletroencefalográficos nas regiöes fronto temporais com o intuito de se comparar a eficácia dos eletrodos zigomáticos anteriores e posteriores

Secçäo microcirúrgica do corpo caloso (calosotomia) no tratamento das epilepsias generalizadas / Microsurgical section of the corpus collosum (Collosotomy) as a treatment for generalized epilepsy

15 pacientes portadores de Epilepsia Generalizada näo controlável por meditaçäo foram submetidos a secçäo parcial do Corpo Caloso, como forma auxiliar de controle terapêutico de crises generalizadas menores, principalmente constituídas por ausências e crises atômicas. Os critérios neurológicos e eletroencefalográficos de seleçäo para indicaçäo cirúrgica estäo relacionados à freqüente presença de acentuaçäo multifocal de alteraçöes difusas da excitabilidade cortical encontradas nas epilepsias generalizadas secundárias. Os aspectos epileptológicos e eletroencefalográficos dos estudos pré e pós-operatórios säo discutidos