Non-invasive brain stimulation and computational models in post-stroke aphasic patients: single session of transcranial magnetic stimulation and transcranial direct current stimulation. A randomized clinical trial

ABSTRACT CONTEXT AND OBJECTIVE: Patients undergoing the same neuromodulation protocol may present different responses. Computational models may help in understanding such differences. The aims of this study were, firstly, to compare the performance of aphasic patients in naming tasks before and after one session of transcranial direct current stimulation (tDCS), transcranial magnetic stimulation (TMS) and sham, and analyze the results between these neuromodulation techniques; and secondly, through computational model on the cortex and surrounding tissues, to assess current flow distribution and responses among patients who received tDCS and presented different levels of results from naming tasks. DESIGN AND SETTING: Prospective, descriptive, qualitative and quantitative, double blind, randomized and placebo-controlled study conducted at Faculdade de Ciências Médicas da Santa Casa de São Paulo. METHODS: Patients with aphasia received one session of tDCS, TMS or sham stimulation. The time taken to name pictures and the response time were evaluated before and after neuromodulation. Selected patients from the first intervention underwent a computational model stimulation procedure that simulated tDCS. RESULTS: The results did not indicate any statistically significant differences from before to after the stimulation.The computational models showed different current flow distributions. CONCLUSIONS: The present study did not show any statistically significant difference between tDCS, TMS and sham stimulation regarding naming tasks. The patients'responses to the computational model showed different patterns of current distribution.

Multiple sclerosis and herpesvirus interaction / Esclerose multipla e interacao com os herpesvirus

Multiple sclerosis is the most common autoimmune inflammatory demyelinating disease of the central nervous system, and its etiology is believed to have both genetic and environmental components. Several viruses have already been implicated as triggers and there are several studies that implicate members of the Herpesviridae family in the pathogenesis of MS. The most important characteristic of these viruses is that they have periods of latency and exacerbations within their biological sanctuary, the central nervous system. The Epstein-Barr, cytomegalovirus, human herpesvirus 6 and human herpesvirus 7 viruses are the members that are most studied as being possible triggers of multiple sclerosis. According to evidence in the literature, the herpesvirus family is strongly involved in the pathogenesis of this disease, but it is unlikely that they are the only component responsible for its development. There are probably multiple triggers and more studies are necessary to investigate and define these interactions.

A esclerose múltipla é a doença inflamatória auto-imune mais comum do sistema nervoso central. Sua etiologia já foi creditada apresentar tanto causas genéticas quanto ambientais. Vários vírus já foram implicados como desencadeadores desta doença e existem inúmeros trabalhos fazendo correlação entre a família Herpesviridae e a patogênese da esclerose múltipla. As características mais importantes dos Herpesviridae são as de apresentarem períodos de latência e exacerbação e terem como seu principal santuário biológico o sistema nervoso central. O vírus Epstein-Barr, o citomegalovírus, o herpesvirus tipo 6 e herpesvirus tipo 7 são os membros mais estudados como desencadeadores da esclerose múltipla. Conforme as evidencias que a literatura apresenta a família Herpesviridae está fortemente envolvida na patogênese da esclerose múltipla, porém é pouco provável que sejam os únicos responsáveis pelo seu início. É provável que esta doença apresente inúmeros desencadeadores e mais estudos são necessários para determinar estas interações.

Medication withdrawal may be an option for a select group of patients in relapsing-remitting multiple sclerosis / Retirada de medicacao pode ser uma opcao para um grupo selecionado de pacientes com esclerose multipla remitente-recorrente

This article describes the clinical and radiological evolution of a stable group of patients with relapsing-remitting multiple sclerosis that had their disease-modifying therapy (DMT) withdrawn. Forty patients, which had made continuous use of one immunomodulator and had remained free of disease for at least 5 years, had their DMT withdrawn and were observed from 13 to 86 months. Out of the followed patients, 4 (10%) patients presented with new attacks. In addition to these patients, 2 (5%) patients had new lesions revealed by magnetic resonance imaging that did not correspond to clinical attacks. Despite these results, the difficult decision to withdraw medication requires careful analysis. Withdrawal, however, should not be viewed as simply the suspension of treatment because these patients should be evaluated periodically, and the immunomodulators should be readily reintroduced if new attacks occur. Nonetheless, medication withdrawal is an option for a select group of patients.

Esse artigo descreve a evolução clínica e radiológica de um grupo de pacientes com esclerose múltipla estável, forma recorrente-remitente, nos quais foi retirada a terapia modificadora da doença (DMT). Quarenta pacientes, que faziam uso contínuo de um imunomodulador e permaneceram livres da doença pelo menos por 5 anos, tiveram sua DMT retirada e foram observados de 13 a 86 meses. Dos pacientes seguidos, 4 (10%) apresentaram novos surtos. Além destes, 2 (5%) pacientes apresentavam novas lesões na ressonância magnética, sem sintomas clínicos. Apesar destes resultados, a retirada da medicação é uma decisão difícil, requer análise cuidadosa e não deve ser considerada como sinônimo de suspender o tratamento, já que estes pacientes devem ser avaliados periodicamente e o uso de imunomoduladores tem de ser prontamente reiniciado no caso do aparecimento de novos surtos. Não obstante, a retirada do medicamento é uma opção para um grupo selecionado de pacientes.