Cerebral structural and functional changes in diabetes mellitus

Diabetes mellitus (DM) is a metabolic disease that is accompanied by brain injury manifested as cognitive impairment (CI). Objective : to study cerebral structural and functional changes in patients with DM according to the presence of CI. Patients and methods . Examinations were made in 60 patients with type 1 DM and 60 with type 2 DM who were divided into groups according to the presence of CI. The Montreal Cognitive Assessment (MoCA test) was used to evaluate CI. Glycemia and its variability and the level of glycated hemoglobin (HbA1c) were analyzed. MRI brain images were segmented using the FreeSurfer program and the Recon-all software package. Brain functional MRI was performed using paradigms (for Broca's, Wernicke's and primary motor areas). Results and discussion . Patients with type 1 DM and CI were found to have reduced volumes of the entire white matter and the right hippocampus; those with type 2 DM had decreased gray and white matter volumes. The functional activities of the primary motor and Broca's areas were reduced by 50% in patients with types 1 and by 80% in those with type 2 when conducting the tasks. A relationship was established between disease duration, patient age, glycemic variability index, MoCA test results, and decreases in the volumes of the hippocampus and white and gray matter and in the activity of motor areas in types 1 and 2 DM. Conclusion . Gray and white matter atrophy and impaired motor area functional activity are more significant in type 2 DM. These changes are associated with CI and glycemic variability.