Investigation of Neuropsychological Criteria in Neurodegenerative Processes with Structural Magnetic Resonance Imaging. Istanbul University Institute of Health Science, Department of Neuroscience

The aim of the study is to measure morphological changes using the Magnetic Resonance Imaging (MRI) method in individuals diagnosed with Mild Cognitive Impairment (MCI), which is defined as the prodromal stage in the course of Alzheimer's Disease (AD). For this purpose, MCI patients were divided into two groups based on their episodic memory performance and volumetric measures, cortical thickness, and white-matter hyperintensity load were analyzed between two groups. 49 patients diagnosed with amnestic MCI were divided into two groups as early stage (E-MCI) and late stage (L-MCI) of MCI according to an episodic memory test, Free and Clueless Selective Recall Test (FCSRT). Total cortical volume, hippocampal subfield volumes and cortical thickness values were measured using FreeSurfer (FS) program. White-matter hyperintensities were examined with the Age-Related White Matter Changes Scale (ARWMC). Statistical Package for Social Sciences Software (SPSS) was used for all statistical analyzes. Volumetric analysis results revealed no difference in total cortex, white-matter and left and right hippocampal volumes between the groups. According to the linear regression analysis, a significant relationship between left hippocampal fissure and FCSRT scores were found, [B= -0.39, p= 0,006 (<0,05)]. For cortical thickness measurements, no difference was observed between groups. L-MCI patients showed significantly increased white-matter hyperintensities in the left frontal (U= 187, p= 0,011) and right frontal (U= 197, p= 0,022) regions compared to E-MCI group. These findings show that white-matter hyperintensities might underlie the memory impairment seen in the MCI patients. Key words: Alzheimer's disease, mild cognitive impairment, episodic memory, white-matter hyperintensity.