N-BACK TASK IN PATIENTS WITH DEMENTIA AND DEPRESSION COMPARED TO PATIENTS WITH ONLY DEPRESSION: CARDIOVASCULAR PATHOLOGY WITHOUT AND WITH DIABETES MELLITUS

Abstract

The role of diabetes mellitus (DM) in cognitive decline in Alzheimer Disease (AD) remains unclear. In our previous study we did not find any additional impact of DM on the cognitive performance in demented patients with cardiovascular pathology (Bragin et al., 2013). The goal of this study is to implement the more challenging N-back task to investigate possible impact of DM in patients with dementia and depression and patients with depression alone. Data was collected from the charts of 409 patients (133 males, 276 females), mean age 76.7 ± 6.1, education 13.8 ± 2.5 yrs, all with cardiovascular pathology and with or without DM. All patients were divided into 2 groups: group 1 - patients with dementia and depression (N=318) and group 2 - patients with Depression alone (N=91). The patients in each group were further divided into subgroups of patents with No DM and DM. The cognitive battery included the MMSE, the clock drawing (CDT), the verbal fluency category (VFC) and letters (VFL) tasks, computerized simple (SRT), complex (CRT) reaction time tasks and the N-2 Back Task with non-verbal stimuli (textures) as a target. Statistical analysis was done on SPSS-21. There were no statistically significant differences in most of the cognitive tasks between No DM and DM subgroups in group 1 (dementia and depression). In group 2 (depression), the only difference between DM and No DM subgroups was on mean reaction time in N-back task. It was 1030.87± 224.87ms for no DM and 1202 ± 352.70 ms for DM (p<0.037). The N-back task reaction time is slower only in the subgroup of patients with depression and diabetes. For patients with dementia, depression and diabetes, practical application of N-back task to differential diagnostics needs further investigation.