Atypical language organization in temporal lobe epilepsy revealed by a passive semantic paradigm

Background Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults and can be successfully cured by surgery. One of the main complications of this surgery however is a decline in language abilities. The magnitude of this decline is related to the degree of language lateralization to the left hemisphere. Most fMRI paradigms used to determine language dominance in epileptic populations have used active language tasks. Sometimes, these paradigms are too complex and may result in patient underperformance. Only a few studies have used purely passive tasks, such as listening to standard speech. Methods In the present study we characterized language lateralization in patients with MTLE using a rapid and passive semantic language task. We used functional magnetic resonance imaging (fMRI) to study 23 patients [12 with Left (LMTLE), 11 with Right mesial temporal lobe epilepsy (RMTLE)] and 19 healthy right-handed controls using a 6 minute long semantic task in which subjects passively listened to groups of sentences (SEN) and pseudo sentences (PSEN). A lateralization index (LI) was computed using a priori regions of interest of the temporal lobe. Results The LI for the significant contrasts produced activations for all participants in both temporal lobes. 81.8% of RMTLE patients and 79% of healthy individuals had a bilateral language representation for this particular task. However, 50% of LMTLE patients presented an atypical right hemispheric dominance in the LI. More importantly, the degree of right lateralization in LMTLE patients was correlated with the age of epilepsy onset. Conclusions The simple, rapid, non-collaboration dependent, passive task described in this study, produces a robust activation in the temporal lobe in both patients and controls and is capable of illustrating a pattern of atypical language organization for LMTLE patients. Furthermore, we observed that the atypical right-lateralization patterns in LMTLE patients was associated to earlier age at epilepsy onset. These results are in line with the idea that early onset of epileptic activity is associated to larger neuroplastic changes

Health, environment and working conditions in tobacco cultivation: a review of the literature Saúde, ambiente e condições de trabalho no cultivo de tabaco: revisão de literatura

This study presents a review of the literature published between 1979 and 2010 on health and working conditions in tobacco cultivation, with particular emphasis on the Brazilian context. A review of computerized databases (PubMed, Scopus, WilsonWeb and Bireme/PAHO Virtual Health Library - Public Health) was carried out using the following search terms: tobacco, agricultural worker health, agricultural worker disease, working conditions, unsafe working conditions, occupational risk, occupational disease, and labor force. Articles published in English, Spanish and Portuguese were analyzed. Thirty-seven articles were selected from 214 references that were initially identified. Thirty-four additional publications (reports, etc.) were also analyzed. Among the many effects described in the literature, especially noteworthy are "green tobacco sickness," respiratory disorders, musculoskeletal injuries, mental disorders, and a negative environmental impact. Very few studies have been carried out in Brazil.<br>Este estudo propõe uma revisão da literatura científica publicada entre 1979 e 2010, sobre condições de trabalho no cultivo do tabaco, como ênfase particular no contexto brasileiro. Foi realizada revisão de literatura com consulta às bases de dados Pubmed, Scopus, Wilson Web e BVS - Saúde Pública (Bireme OPAS). Os descritores utilizados foram: tabaco, saúde do trabalhador rural, doença dos trabalhadores agrícolas, condições de trabalho, condições inseguras no trabalho, doenças do trabalho e força de trabalho. Foram selecionados artigos publicados em inglês, espanhol e português. Trinta e sete artigos foram selecionados a partir de 214 referências que foram inicialmente identificados. Trinta e quatro outras publicações (relatórios técnico, livros e outros) também foram analisadas. Entre os muitos efeitos descritos na literatura, destaca-se "doença da folha do tabaco verde", distúrbios respiratórios, lesões músculo-esqueléticas, doenças mentais, e um impacto negativo relacionado ao meio ambiente. No Brasil poucos estudos têm sido realizados sobre este tema