Centro-median stimulation yields additional seizure frequency and attention improvement in patients previously submitted to callosotomy

AbstractRationaleDeep brain stimulation (DBS) has been increasingly used in the treatment of refractory epilepsy over the last decade. We report on the outcome after thalamic centro-median (CM) DBS in patients with generalized epilepsy who had been previously treated with extended callosal section.MethodsFour consecutive patients with generalized epilepsy who were previously submitted to callosal section and had at least 1 year of follow-up after deep brain implantation were studied. Age ranged from 19 to 44 years. All patients were submitted to bilateral CM thalamic DBS. Post-operative CT scans documented the electrode position in all patients. All patients had pre- and post-stimulation prolonged interictal scalp EEG recordings, including spike counts. Attention level was evaluated by means of the SNAP-IV questionnaire. The pre-implantation anti-epileptic drug regimen was maintained post-operatively in all patients.ResultsPost-operative CT documented that all electrodes were correctly located. There was no morbidity or mortality. Seizure frequency reduction ranging from 65 to 95% and increased attention level was seen in all patients. Interictal spiking frequency was reduced from 25 to 95%, but their morphology remained the same. There was re-synchronization of interictal discharges during slow-wave sleep in 2 patients.ConclusionAll patients benefit from the procedure. The CM seems to play a role in modulating the epileptic discharges and attention in these patients. On the other hand, it is not the generator of the epileptic abnormality and appeared not to be involved in non-REM sleep-related interictal spiking modulation

Interações bilaterais no sistema óptico acessório de pombos: um estudo neuroanatômico eletrofisiológico

The accessory optic system (AOS) has been object of extensive investigation in the last few years, mainly after the demonstration of its involvement whit visuomotor, and specially oculomotor, mechanisms. An interesting pattern that has emerged from these studies relates to the possible existence of reciprocai connections between the main accessory optic nuclei. The present study aimed to analyze this point of the functional organization of AOS in pigeons, by neuroanatomical andelectrophysiological methods. Electrophoretic injections of horseradish paroxidase (HRP) or wheat germ agglutinin-HRP (WGA-HRP) were made into the nucleus of the basal optic root (nBOR) of the AOS. In separate experiments, unitary and field potential recordings were performed in the same nucleus, while electrically stimulating the contralateral nBOR and optic nerve. The main results are summarized bellow. 1) Retrogradely labeled neurons were found in the contralateral nBOR, in its central, dorsal and lateral portions. 2) Electrical stimulation of nBOR could evoke field potentials in the contralateral nBOR, both anti-and orthodromic. 3) nBOR unitary activity could be abolished, depressed or even slightly increased by pulses applied in the contralateral nBOR. Inhibition by long periods was the dominant pattern in these experiments, and could also be observed upon optic nerve evoked firing. The above data confirm the existence of reciprocai connections between main accessory optic nuclei in pigeons, besides indicating that nBOR receives a powerful influence from its contralateral counterpart. This could represent an important mechanism in oculomotor control functions in birds and perhaps other vertebrates as well.O sistema óptico acessório (SOA) tem sido objeto de intensa investigação nos últimos anos, sobretudo após a demonstração de suas ligações com mecanismos de integração visuo-motora. Um aspecto interessante emergente desses estudos, realizados principalmente em aves, diz respeito à possível existência de conexões recíprocas entre os núcleos principais desse sistema, bilateralmente. O presente estudo visou estudar esse aspecto da organização funcional do SOA em pombos, por métodos neuroanatômicos e eletrofisiológicos. Microinjeções eletroforéticas de peroxidase do rábano silvestre (HRP) ou HRP conjugada à aglutinina do germe de trigo (WGA-HRP) foram efetuadas no núcleo da raiz óptica basal (nROB), principal componente do SOA em aves. Em experimentos separados, foram feitos registros unitários e de campo no nROB, e aplicados pulsos elétricos no nROB contralateral o no trato óptico. Os principais resultados obtidos podem ser resumidos como segue: 1) Neurônios marcados retrogradamente por HRP ou WGA-HRP foram encontrados no nROB contralateral, em suas regiões central, dorsal e lateral. 2) A estimulaçao elétrica do nROB pode gerar potenciais de campono nROB contralateral, anti e ortodrômicos, 3) A atividade unitária no nROB pode ser suprimida, reduzida ou mesmo levemente facilitada pelos pulsos aplicados no nROB contralateral. Inibição pareceu o efeito predominante e pode ser observada também sobre atividade provocada a partir do trato óptico. Estes dados confirmam a existência de conexões inter-hemisféricas no SOA de pombos, indicando ainda que o nROB está sujeito a uma importante ação modulatória a partir de seu equivalente contralateral. Isto poderia representar um importante mecanismo de controle oculomotor nesses animais e talvez outros vertebrados

Cardiac troponin I levels in patients with refractory temporal lobe epilepsy after cortico-amygdalo-hippocampectomy

PURPOSE: Sudden unexpected death in epilepsy (SUDEP) is the main cause of death in patients with epilepsy. Morphologic and functional changes in the heart are related to SUDEP. The aim of our study was to verify the concentration of troponin I, an important marker of myocardium damage, in patients with temporal lobe epilepsy who were submitted to surgical resection and were not seizure-free after the procedure. METHODS: Eleven non-consecutive patients participated in the study and all of them presented poor seizure control after surgical procedure. Troponin I levels higher then 1 ng/ml indicate myocardium damage. The detection level of the kit used in our study was 0,15 ng/ml. RESULTS: Only three patients showed detectable troponin I levels. The troponin I levels found in our study is not related with sex, age or side of the lesion. CONCLUSIONS: In spite of we did not find positive results in our study, an active role of the heart in SUDEP cannot be discarded, since some injuries, even so not being capable to modify troponin I levels, can be enough to generate arrhythmogenic foci.OBJETIVOS: A morte súbita em epilepsia (SUDEP) é a principal causa de morte entre os pacientes com epilepsia. Alterações morfológicas e funcionais do coração estão relacionadas com a SUDEP. Nesse sentido, o objetivo deste estudo foi avaliar a concentração de troponina I, um importante marcador de lesão do miocárdio, em pacientes com epilepsia do lobo temporal de difícil controle e que foram submetidos à ressecção cirúrgica e que não obtiveram sucesso com esta abordagem terapêutica. METODOLOGIA: Onze pacientes participaram do estudo e todos continuaram a apresentar crises após o tratamento cirúrgico. Os valores de troponina I indicativos de lesão seriam aqueles maiores de 1 ng/ml e o valor mínimo detectável pelo kit utilizado em nosso estudo foi de 0,15 ng/ml. RESULTADOS: Apenas três pacientes apresentaram níveis de troponina I detectáveis. Em relação aos níveis detectáveis de troponina I, não encontramos nenhuma relação com sexo, idade e lateralidade da lesão. CONCLUSÕES: APESAr de não termos encontrado resultados positivos em nosso estudo, o papel do coração na SUDEP não pode ser descartado, já que algumas lesões, embora não sendo capazes de alterar os níveis séricos de troponina I, podem ser suficientes na gênese de focos arritmogênicos.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade de Mogi das Cruzes Núcleo de Pesquisas TecnológicasHospital Brigadeiro Departamento de Neurologia e NeurocirurgiaCentro Universitário São CamiloHospital Israelita Albert EinsteinUniversidade Federal de São João del-Rei Departamento de Engenharia BiomédicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de FisiologiaUNIFESP, EPM, Depto. de FisiologiaSciEL