Current language mapping protocols for neurosurgical planning are invasive, expensive, and not suitable for all surgical candidates. We investigated the potential of dense array EEG to determine hemispheric dominance for language and localize current sources of semantic and lower level language functions in the brain using a semantic decision task, a phonological decision task, and an acoustic decision task. Source estimates of N400-window ERPs (N365, N480) and the Late Positive Complex (LPC) localized strongly to medial temporal regions. Overall source estimates revealed a slight left lateralized network, with more posterior engagement for the semantic condition and more anterior engagement for the phonological condition. Source localization of the resulting t-test wave from the semantic - phonological highlighted a stronger left lateralized pattern of activation encompassing more of the semantic network. As a first pass these results are promising, but need to be investigated on individual subject ERPs.

Lumbar fusion performed among injured workers has dramatically increased over the past two decades, coinciding with the increased use of more advanced surgical technology. Despite recent changes in how this surgery is performed, few outcome studies have been conducted, particularly among workers compensation populations. In prior studies, several biopsychosocial risk factors were found to be predictors of functional outcomes of lumbar fusion. Considering the recent changes in lumbar fusion surgery, there is a need to identify how patient outcomes have changed among injured workers, and whether a biopsychosocial model continues to be predictive of outcomes. The current study aimed to address multidimensional patient outcomes associated with lumbar fusion and examine the relationship between presurgical biopsychosocial variables and outcomes by testing the predictive efficacy of a multiple variable model. Injured workers (N = 245) who underwent their first lumbar fusion between 1998 and 2007 were included in a retrospective-cohort study performed in two phases that involved coding presurgical information documented in patient medical charts in the Worker's Compensation Fund of Utah computer database (Phase 1) and administering a telephone outcome survey with patients at least 2 years post-surgery (Phase 2). Of the total sample, 45% (n = 110) of patients were contacted and completed follow-up outcome surveys on several measures of patient satisfaction, quality of life, fusion status, dysfunction level, disability status, pain, and general physical and mental health functioning. Results revealed injured workers reported a solid fusion rate of 89.0%, disability rate of 28.7%, and a poor outcome rate of 57.1%. Multiple linear regression analyses demonstrated an eight variable model was a statistically significant predictor of multiple patient outcomes. Involvement of a nurse case manger, vocational rehabilitation, and litigation at the time of fusion were the most prominent predictors across outcome measures, while age and depression history showed modest prediction of outcomes. Prior back operations, number of vertebral levels fused, and type of instrumentation showed no statistically significant prediction of outcomes. Results were evaluated and compared to prior lumber fusion studies on injured worker and fusion outcome literature, in general. Specific implications for our findings and limitations associated with this study were addressed.

Lumbar fusion surgery is a commonly used procedure to treat severe spinal pathology and associated chronic disabling low back and leg pain. Despite the common incidence of spinal fusion surgery, few studies have examined patient outcomes or predictive correlates of this procedure. The objectives of this study were to characterize Utah workers who received lumbar fusion surgery in terms of relevant presurgical and outcome variables and to identify presurgical correlates of patient outcomes. An archival prospective research design was utilized consisting of a retrospective medical chart review and a postsurgical telephone outcome survey. Subjects were 203 workers' compensation patients from the state of Utah who have undergone spinal fusion surgery and who were at least 2 years postsurgery at time of follow-up. Outcomes were assessed for 144 of the 203 patients (71%). Presurgical measures _included demographic, work, compensation, disability, health, surgical, and physiological variables. Outcome measures included solid arthrosis, patient satisfaction, work disability status, functional disability due to back pain, and multidimensional health. Analysis of patient outcome data revealed that solid arthrosis was achieved in 71.9% of patients. Forty-six percent of subjects felt their back/leg pain problems were worse than what they had expected following the surgery, and 42 % felt that their quality of life had not changed or worsened as a result of lumbar fusion. Twenty-eight percent of fusion patients were work disabled at follow-up. Fusion patient mean outcome scores on multidimensional health measures reflected poorer health than comparative medical patient and nonpatient norms. The most consistent presurgical correlates across outcomes were lawyer involvement, number of prior low back operations, age at injury, and household income at time of injury. Results are compared to data from previous lumbar fusion research studies and reasons for varying findings are offered. Implications of the findings are discussed in terms of inadequate patient selection and insufficient assessment of patient outcomes in low back research studies. Limitations of the present research are discussed, including how placebo, natural history, and regression to the mean can lead to erroneous conclusions about the efficacy of lumber fusion surgery. Suggestions for improvements in low back surgery outcome research are offered.

Rates of lumbar fusion surgery have been increasing with an estimated 192,000 procedures performed annually. However, satisfactory outcomes of lumbar fusion vary considerably and often emphasize technical success, such as arthrodesis, rather than Ill functional and quality of life outcomes. Interbody cage fusion was recently developed and touted as a superior alternative to existing lumbar fusion procedures. There is, however, a paucity of research to support these claims, particularly with regards to functional and quality of life outcomes. Moreover, predictive correlates of outcomes for interbody cage fusion have not been given adequate attention in the literature. The aims of this study were to characterize patients undergoing this new procedure, examine functional and multidimensional outcomes, and investigate the predictive efficacy of presurgical variables. A retrospective cohort research design was employed and entailed medical record reviews for presurgical data and telephone outcome surveys at least 18 months following surgery. Seventy-three patients who had undergone lumbar interbody cage fusion were identified from the private practice of an orthopedic surgeon and the Workers' Compensation Fund of Utah. Presurgical variables coded for analysis included age at the time of surgery, severity rating of presurgical spinal pathology, smoking tobacco, depression, and pursuing litigation at the time of surgery. Of the total sample, 56 patients (76.7%) completed outcome surveys that assessed patient satisfaction, back-specific functioning, disability status, and physical and mental health functioning. While arthrodesis was achieved for most patients (84%), almost half were dissatisfied with their current back condition. Outcomes regarding disability and functioning were mixed. Arthrodesis was only moderately associated with better outcome and for a quite limited set of measure s. Three of the five presurgical variables (tobacco use, depression, and litigation) were consistently predictive of patient outcomes. Findings are discussed and compared to existing data on lumbar fusion procedures , and clinical implications for improved patient selection and possible interventions are highlighted. Consideration is given to the limitations of this study, such as retrospective design, no matched controls , and sample size. Directions for future research are suggested.

In cases of temporal lobe epilepsy, seizures are often controlled by anterior temporal lobe resection. However, an assessment of the impact of surgery on language is required. Currently-used assessments are either non-specific within regions or use functional magnetic resonance imaging (fMRI), which can suffer signal distortion in the temporal lobes due to the presence of airways. Magnetoencephalography (MEG) shows a complimentary sensitivity, but has not been used for laterality assessment. We present a method that combines fMRI with MEG for optimized sensitivity. MEG activation maps were generated using a beamformer, showing activity in the anterior temporal lobes and lateral occipital cortex. fMRI showed activation in medial temporal lobe regions, the frontal poles and the hippocampus, an area of clinical concern during surgical planning. The present study introduces a method for integrating MEG and fMRI activation to create high-resolution laterality maps in regions of concern for epilepsy.

p. 1-83 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-10T18:52:41Z No. of bitstreams: 2 Tese Ionar Rezende seg 01.pdf: 429852 bytes, checksum: a300b0a96f159ce241218cb67611c373 (MD5) Graficos do Artigo Ionar Rezende 02.pdf: 31710 bytes, checksum: e4cdb940c99cc978728315bdf29640d5 (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-22T19:43:49Z (GMT) No. of bitstreams: 2 Tese Ionar Rezende seg 01.pdf: 429852 bytes, checksum: a300b0a96f159ce241218cb67611c373 (MD5) Graficos do Artigo Ionar Rezende 02.pdf: 31710 bytes, checksum: e4cdb940c99cc978728315bdf29640d5 (MD5) / Made available in DSpace on 2013-04-22T19:43:49Z (GMT). No. of bitstreams: 2 Tese Ionar Rezende seg 01.pdf: 429852 bytes, checksum: a300b0a96f159ce241218cb67611c373 (MD5) Graficos do Artigo Ionar Rezende 02.pdf: 31710 bytes, checksum: e4cdb940c99cc978728315bdf29640d5 (MD5) Previous issue date: 2006 / Objetivo: Comparar a Avaliação Muscular Subjetiva com métodos objetivos de avaliação nutricional em pacientes que serão submetidos à cirurgia. Métodos: Trata-se de um estudo de comparação entre métodos de avaliação nutricional, com características transversais, envolvendo dados primários em pacientes no pré-operatório. Realizaram-se medidas antropométricas, laboratoriais e a Avaliação Muscular Subjetiva para diagnóstico nutricional dos pacientes. Utilizou-se o Coeficiente de Tau-b de Kendall, adotando-se como concordância excelente entre os métodos valores maiores ou iguais 80%. Resultados: Para a Avaliação Muscular Subjetiva os valores observados no teste de concordância inter e intra examinador foram 77% e 89%, respectivamente. Os grupamentos musculares que apresentaram maior percentual de alterações tróficas foram o temporal e masseter para ambos os sexos (F=53, 5%; M=82, 0%). Para o sexo feminino, o grau de concordância entre a Avaliação Muscular Subjetiva e os métodos objetivos foi baixo (<51%), exceto para albumina e músculo gastrocnêmio (83 0%). Encontrou-se para o sexo masculino, Coeficiente de Kendall com valores entre 60% e 70%, representando boa concordância (≥60% e ≤ 80%) ao compararmos o índice de massa corporal e a circunferência do braço com os músculos da deambulação, da mastigação e dos interósseos. Conclusões: 1. A Avaliação Muscular Subjetiva apresentou boa reprodutibilidade diagnóstica; 2. Alterações tróficas subjetivas foram prevalentes nos músculo temporal e masseter; 3. Não encontramos concordância excelente entre a Avaliação Muscular Subjetiva e os métodos objetivos de avaliação nutricional para ambos os sexos, exceto entre a albumina a o músculo gastrocnêmio para o sexo feminino. / Salvador

Considerada uma área segura, a região anterior da mandíbula, entre os forames mentuais, abriga muitas estruturas vitais e é passível de muitas intervenções cirúrgicas como colocação de implantes osseointegrados e alguns procedimentos da Cirurgia Ortognática. O Canal Incisivo (CI) é um importante reparo anatômico localizado nessa região e é muitas vezes desconsiderado e nesses casos pode acarretar complicações cirúrgicas. O planejamento radiográfico é um dos mais importantes aspectos pré-cirúrgicos para que não haja injúria dessas importantes estruturas, entretanto, as radiografias convencionais usadas atualmente (intraorais e panorâmica) apresentam uma grande limitação no que se trata da interpretação do CI. A Tomografia Computadorizada Volumétrica de Feixe Cônico (TCFC) oferece a obtenção da imagem do canal incisivo em três dimensões permitindo um completo estudo do seu trajeto e morfologia. Objetivo: Estabelecer as taxas de visibilidade, o comprimento, a localização, o diâmetro e o curso do CI por meio da TCFC e Panorâmica Digital. Material e Métodos: O grupo de estudo consistiu em 100 exames de mandíbula de pacientes adultos realizados por meio da TCFC com protocolo de aquisição padronizado e Panorâmica Digital dos mesmos pacientes obtidos dos arquivos de imagem do Departamento de Estomatologia da Faculdade de Odontologia de Bauru. As imagens foram obtidas pelo dispositivo i-CAT Classic e analisadas pelo i-CAT Vision software em sala adequada. As taxas de visibilidade do CI nas reformatações panorâmicas, digitais e coronais, seu comprimento e localização foram analisando bilateralmente a partir dos forames mentuais até a linha média mandibular. Posteriormente foi feita uma comparação da visibilidade do CI com a radiografia panorâmica digital dos mesmos pacientes. Resultados: Na Panorâmica Digital a visualização do CI foi em média de 20,5% enquanto que na reformatação panorâmica da TCFC a visibilidade foi em torno de 45%. O teste McNemar mostrou diferença estatística significante entre os métodos de aquisição de imagens, indicando a superioridade da TCFC sobre a Panorâmica Digital para a visualização do CI. Na Reformatação Parassagital, a média da visualização do CI foi na área pós-forame de 42%, na região de caninos de 28,5%, na região de incisivos laterais de 11,5% e na região de incisivos centrais foi de 4%. Na Reformatação Coronal, esses valores foram de 68%, 44%, 22% e 9% respectivamente, nas diferentes regiões. A média do comprimento visível do CI a partir do forame mentual foi de 9,2mm nas diferentes reformatações panorâmicas da TCFC. As distâncias médias da reformatação parassagital do CI à base da mandíbula foi de 10,10mm, CI ao ápice dental foi de 8,34mm, do CI ao rebordo alveolar foi de 12,88mm do C a tábua óssea vestibular foi de 4,04mm e do CI à tábua lingual foi de 5,21mm. A trajetória do CI foi de vestibular para lingual e descendente. Não foram encontradas diferenças estatísticas entre a visibilidade do CI em relação e o lado, idade e gênero do paciente. A trajetória do CI foi descendente de vestibular para lingual. Conclusão: A superioridade da TCFC em detectar o CI na região anterior da mandíbula, torna esta modalidade de exame imprescindível na avaliação pré-operatória para procedimentos cirúrgicos desta região. / The mandibular interforaminal region is usually considered a safe area. It heldsvital anatomical structures and common surgical interventions such as placement of dental implants and procedures of orthognathic surgery are performed in this area. The Mandibular Incisive Canal (MIC) is a significant anatomical feature located in this region, often overlooked and that can cause surgical complications.The radiographic planning is one of the most important aspects of presurgical assessment to avoid injuries to these important structures, however, conventional radiographs (intraoral and panoramic) used nowadays remains limited when it comes to interpretation of the incisive canal. Cone beam computed tomography (CBCT) offers tridimensional image of the incisive canal allowing a comprehensive study of its course and morphology Objective: To establish the rate of visibility, length, location and course of CI by means of cone beam computed tomography and on digital panoramic. Material and Methods: The study group consisted of 100 CBCT random scans obtained from the Department of Stomatology of Bauru Dental Schools files. The images were taken using i-Cat CBCT device, applying a standardized exposure protocol and analyzed by i-Cat Vision software. The visibility of IC was studied at panoramic, cross-section and coronal scans. Its length and location were also analyzed from mentual foramen to the mandible midline. Subsequently, a comparison was made with the rates of visibility at the digital panoramic radiography from the same patients. Results: The visualization of the incisive canal at digital panoramic averaged 20.5% while the reconstruction of the CBCT panoramic visibility was around 45%. The McNemar test showed statistical difference, indicating the superiority of CBCT over panoramic radiograph for CI visualization. In crossectional reformatation, the average between the sides in the postforament area was 42%, in the region of canines was 28.5%, in the region of the lateral incisors was 11.5% and in the region of central incisorswas 4%. In coronal reconstruction, these values were 68%, 44%, 22% and 9% in the different regions. The average length of IC visible from the mental foramen was 9.18 mm in the different panoramic reformations. The average distance of crossectional reformatations of IC to the mandibular base was 10.10, IC to the tooth apex was 8.34mm, the IC to the alveolar ridge was 12.87mm, IC to buccal plate was 4.04mm and CI to the lingual plate was 5.21mm. There were no statistical differences in relation to the side, age and gender of the patient.ICs route was downward from the vestibular to the lingual plate. Conclusion: The superiority in the detection and high appearance rates of IC with CBCT showed the great importance of preoperative examination using CBCT for surgical procedures in the anterior mandible.

Considerada uma área segura, a região anterior da mandíbula, entre os forames mentuais, abriga muitas estruturas vitais e é passível de muitas intervenções cirúrgicas como colocação de implantes osseointegrados e alguns procedimentos da Cirurgia Ortognática. O Canal Incisivo (CI) é um importante reparo anatômico localizado nessa região e é muitas vezes desconsiderado e nesses casos pode acarretar complicações cirúrgicas. O planejamento radiográfico é um dos mais importantes aspectos pré-cirúrgicos para que não haja injúria dessas importantes estruturas, entretanto, as radiografias convencionais usadas atualmente (intraorais e panorâmica) apresentam uma grande limitação no que se trata da interpretação do CI. A Tomografia Computadorizada Volumétrica de Feixe Cônico (TCFC) oferece a obtenção da imagem do canal incisivo em três dimensões permitindo um completo estudo do seu trajeto e morfologia. Objetivo: Estabelecer as taxas de visibilidade, o comprimento, a localização, o diâmetro e o curso do CI por meio da TCFC e Panorâmica Digital. Material e Métodos: O grupo de estudo consistiu em 100 exames de mandíbula de pacientes adultos realizados por meio da TCFC com protocolo de aquisição padronizado e Panorâmica Digital dos mesmos pacientes obtidos dos arquivos de imagem do Departamento de Estomatologia da Faculdade de Odontologia de Bauru. As imagens foram obtidas pelo dispositivo i-CAT Classic e analisadas pelo i-CAT Vision software em sala adequada. As taxas de visibilidade do CI nas reformatações panorâmicas, digitais e coronais, seu comprimento e localização foram analisando bilateralmente a partir dos forames mentuais até a linha média mandibular. Posteriormente foi feita uma comparação da visibilidade do CI com a radiografia panorâmica digital dos mesmos pacientes. Resultados: Na Panorâmica Digital a visualização do CI foi em média de 20,5% enquanto que na reformatação panorâmica da TCFC a visibilidade foi em torno de 45%. O teste McNemar mostrou diferença estatística significante entre os métodos de aquisição de imagens, indicando a superioridade da TCFC sobre a Panorâmica Digital para a visualização do CI. Na Reformatação Parassagital, a média da visualização do CI foi na área pós-forame de 42%, na região de caninos de 28,5%, na região de incisivos laterais de 11,5% e na região de incisivos centrais foi de 4%. Na Reformatação Coronal, esses valores foram de 68%, 44%, 22% e 9% respectivamente, nas diferentes regiões. A média do comprimento visível do CI a partir do forame mentual foi de 9,2mm nas diferentes reformatações panorâmicas da TCFC. As distâncias médias da reformatação parassagital do CI à base da mandíbula foi de 10,10mm, CI ao ápice dental foi de 8,34mm, do CI ao rebordo alveolar foi de 12,88mm do C a tábua óssea vestibular foi de 4,04mm e do CI à tábua lingual foi de 5,21mm. A trajetória do CI foi de vestibular para lingual e descendente. Não foram encontradas diferenças estatísticas entre a visibilidade do CI em relação e o lado, idade e gênero do paciente. A trajetória do CI foi descendente de vestibular para lingual. Conclusão: A superioridade da TCFC em detectar o CI na região anterior da mandíbula, torna esta modalidade de exame imprescindível na avaliação pré-operatória para procedimentos cirúrgicos desta região. / The mandibular interforaminal region is usually considered a safe area. It heldsvital anatomical structures and common surgical interventions such as placement of dental implants and procedures of orthognathic surgery are performed in this area. The Mandibular Incisive Canal (MIC) is a significant anatomical feature located in this region, often overlooked and that can cause surgical complications.The radiographic planning is one of the most important aspects of presurgical assessment to avoid injuries to these important structures, however, conventional radiographs (intraoral and panoramic) used nowadays remains limited when it comes to interpretation of the incisive canal. Cone beam computed tomography (CBCT) offers tridimensional image of the incisive canal allowing a comprehensive study of its course and morphology Objective: To establish the rate of visibility, length, location and course of CI by means of cone beam computed tomography and on digital panoramic. Material and Methods: The study group consisted of 100 CBCT random scans obtained from the Department of Stomatology of Bauru Dental Schools files. The images were taken using i-Cat CBCT device, applying a standardized exposure protocol and analyzed by i-Cat Vision software. The visibility of IC was studied at panoramic, cross-section and coronal scans. Its length and location were also analyzed from mentual foramen to the mandible midline. Subsequently, a comparison was made with the rates of visibility at the digital panoramic radiography from the same patients. Results: The visualization of the incisive canal at digital panoramic averaged 20.5% while the reconstruction of the CBCT panoramic visibility was around 45%. The McNemar test showed statistical difference, indicating the superiority of CBCT over panoramic radiograph for CI visualization. In crossectional reformatation, the average between the sides in the postforament area was 42%, in the region of canines was 28.5%, in the region of the lateral incisors was 11.5% and in the region of central incisorswas 4%. In coronal reconstruction, these values were 68%, 44%, 22% and 9% in the different regions. The average length of IC visible from the mental foramen was 9.18 mm in the different panoramic reformations. The average distance of crossectional reformatations of IC to the mandibular base was 10.10, IC to the tooth apex was 8.34mm, the IC to the alveolar ridge was 12.87mm, IC to buccal plate was 4.04mm and CI to the lingual plate was 5.21mm. There were no statistical differences in relation to the side, age and gender of the patient.ICs route was downward from the vestibular to the lingual plate. Conclusion: The superiority in the detection and high appearance rates of IC with CBCT showed the great importance of preoperative examination using CBCT for surgical procedures in the anterior mandible.

Dans le cadre de l’évaluation pré-chirurgicale de patients épileptiques, il est impératif de déterminer la spécialisation hémisphérique du langage, ainsi que de localiser les aires du langage au sein de cet hémisphère. De nouvelles méthodes d’évaluation non- invasives doivent être mises au point afin de diminuer les risques associés aux méthodes plus invasives telles que le test à l’amobarbital intracarotidien (TAI). L’objectif principal de cette thèse est donc de développer un protocole d’évaluation pré-chirurgicale alternatif et non-invasif à l’aide de la magnétoencéphalographie (MEG) pour la latéralisation et la localisation du langage, incluant la mémoire verbale qui serait éventuellement accessible à une population pédiatrique francophone épileptique. L’article 1 présente une recension de la littérature résumant les différentes études en MEG ayant pour objectif l’évaluation pré-chirurgicale du langage. Trente-sept articles en MEG ont été analysés pour déterminer quelles tâches permettaient d’obtenir les meilleurs résultats de latéralisation intrahémisphérique et de localisation du langage pour l’évaluation du langage réceptif et expressif chez des sujets neurologiquement sains et épileptiques. Parmi les tests retenus, l’épreuve de reconnaissance de mots permet d’évaluer le langage réceptif et la mémoire verbale, tandis que des épreuves de fluence verbale telles que la génération de verbes permettent d’évaluer le langage expressif de façon à obtenir de très bons résultats. L’article 2 a permis de valider un protocole auprès de sujets neurologiquement sains à l’aide des épreuves identifiées dans l’article 1. Le protocole utilisé comprend une tâche de langage réceptif et de mémoire verbale (une épreuve de reconnaissance de mots) et une tâche de langage expressif (une épreuve de fluence verbale). Suite à la validation du protocole à l’aide d’analyses par composantes principales, les épreuves ont été administrées à un groupe de patients épileptiques. Les index de latéralité et les analyses de sources i révèlent que la MEG permet de localiser et de latéraliser les fonctions langagières et pourrait donc être utilisée comme méthode d'évaluation du langage lors de l'évaluation pré- chirurgicale auprès de patients épileptiques. Toutefois, alors que l’épreuve de mémoire verbale a permis d’obtenir les meilleurs résultats auprès de l’ensemble des participants, l’épreuve de fluence verbale n’a fourni des informations supplémentaires que chez un seul patient et chez aucun participant neurologiquement sain. En résumé, les deux articles de cette thèse démontrent le potentiel clinique de la MEG pour l’évaluation pré-chirurgicale de patients souffrant d’une épilepsie réfractaire. / It is imperative to determine hemispheric dominance of language and to localize language areas in this hemisphere as part of the presurgical evaluation of epileptic patients. New non-invasive evaluation methods should be developed to reduce the risks associated with more invasive methods such as the intracarotid sodium amobarbital procedure (ISAP). The main objective of this dissertation is to develop an alternative non-invasive presurgical evaluation protocol using magnetoencephalography (MEG) to determine the lateralisation and localization of language and verbal memory that would eventually be accessible to a French-speaking paediatric population suffering from epilepsy. Article 1 is a literature review summarizing MEG studies on the presurgical evaluation of language. Thirty-seven articles were analyzed to determine which tasks allow to obtain the best results with regards to language lateralization and localization with MEG in the assessment of receptive and expressive language in neurologically healthy individuals as well as epileptic patients. We conclude that the word recognition task is well suited to assess receptive language and verbal memory, while a verbal fluency task, such as the verb generation task allows the assessment of expressive language with very good results. Article 2 allowed the validation of a language protocol with neurological healthy participants based on the tasks identified in article 1. The protocol included a task evaluating receptive language functions and verbal memory (word recognition task) and a task evaluation expressive language (verbal fluency). After having validated the tasks using principal component analysis, they were administered to a group of patients with epilepsy. Laterality findings and source analysis showed that MEG can be used to lateralize and localize language and could therefore be used in the presurgical assessment of patients with epilepsy. However, the verbal fluency task, when compared to the verbal memory task, provided additional information for only one patient and in none of the neurologically healthy participants. In summary, the two articles of this dissertation demonstrate the clinical potential of MEG for the presurgical evaluation of patients with refractory epilepsy.