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The primary goal of this study was to test the reliability of presurgical language lateralization in epilepsy patients with functional magnetic resonance imaging (fMRI) with a 1.0-T MR scanner using a simple word generation paradigm and conventional equipment. In addition, hemispherical fMRI language lateralization analysis and region of interest (ROI) analysis in the frontal and temporo-parietal regions were compared with the intracarotid amytal test (IAT). Twenty epilepsy patients under presurgical evaluation were prospectively examined by both fMRI and IAT. The fMRI experiment consisted of a word chain task (WCT) using the conventional headphone set and a sparse sequence. In 17 of the 20 patients, data were available for comparison between the two procedures. Fifteen of these 17 patients were categorized as left hemispheric dominant, and 2 patients demonstrated bilateral language representation by both fMRI and IAT. The highest reliability for lateralization was obtained using frontal ROI analysis. Hemispherical analysis was less powerful and reliable in all cases but one, while temporo-parietal ROI analysis was unreliable as a stand-alone analysis when compared with IAT. The effect of statistical threshold on language lateralization prompted for the use of t-value-dependent lateralization index plots. This study illustrates that fMRI-determined language lateralization can be performed reliably in a clinical MR setting operating at a low field strength of 1 T without expensive stimulus presentation systems. [ABSTRACT FROM AUTHOR]

Introduction: Rapidly increasing aging of the world's population is causing a heightened prevalence of Alzheimer's disease (AD) and mild cognitive impairment (MCI). The global burden, caused by this, is tremendous. In order to slow down the progression of the disease and preserve quality of life as much as possible, early identification of subjects at risk is indispensable within this framework., Methods: In the present study, we combined independent component analysis and statistical parametric analysis to identify and compare the default-mode network (DMN) in healthy elderly and patients with MCI, with a special interest for hippocampal and lateral temporal involvement., Results: Functional results indicated reduced cortical activation in the DMN for MCI patients, compared with age- and education-matched healthy elderly controls, mainly in the retrosplenial region/posterior cingulate cortex, left hippocampus, and bilateral inferior and middle frontal areas. Increased activation for patients was observed in the medial prefrontal and bilateral middle temporal/angular cortex. Lateral temporal involvement in the DMN was in both the elderly control samples, and the patient group detected and suggested a slightly increased activation, more right than left, in middle temporal areas in the MCI patients, compared with healthy elderly., Conclusion: Results are discussed with reference to the existing literature on early pathological changes in MCI and AD and subsequent compensation mechanisms in resting state and memory circuits.