Late-life depression is a complex condition impacted by both mental and physical health outcomes and psychosocial factors. Psychosocial predictors of depression are reliant on cultural factors including socioeconomic variables, stigmas, and cultural values. Most research on late-life depression and its effect on cognitive functioning has been completed in so-called Western, Educated, Industrialized, Rich, and Democratic (WEIRD) populations and findings may not generalize to older adults living in other areas of the world. The current study explored predictors of depressive symptoms as well as the association between depressive symptoms and neuropsychological functioning in Congolese older adults.

A total of 319 participants (mean age=72.7±6.15, mean education in years=7.6±4.56; 47% female) were randomly recruited. Depressive symptoms were assessed with the Geriatric Depression Scale. Given the exploratory nature of the current study, forward stepwise linear regression models were run to assess predictors of depressive symptoms. The independent variables assessed as potential predictors included age, years of education, gender, participant income, parental income, living arrangement (i.e., alone or with others), functional abilities (FAQ), fragility, and self-rated overall health. Analyses were run in the overall sample as well as stratified by gender. The association between depressive symptoms and performance on the Community Screening Instrument for Dementia (SCID) was also explored.

Higher depressive symptoms were found in women (ß=.228, p=0.036), those with lower parental income (ß=-.156, p=.005), higher fragility (ß=-.237, p<.001), and worse overall health (ß=-.311, p=.020). Among women, lower parental income, (ß=-.230, p=.002), higher fragility (ß=-.312, p<.001), and lower overall health (ß=-.235, p=.004) predicted higher depressive symptoms, while in men only higher fragility (ß=-.164, p=.041) and living alone (ß=-.184, p=.022) predicted higher depressive symptoms. There was also a significant association between depressive symptoms and lower scores on the CSID (ß=-.189, p=.001)

Similar to results in WEIRD populations, general health and fragility predicted depressive symptoms in Congolese older adults. However, parental income (more so than participant income) also predicted depressive symptoms in Congolese older adults, particularly in women, while living alone was a predictor in Congolese older men. It is possible that the difference in depressive symptoms between men and women is driven by underreporting of depressive symptoms among men. Our results also showed that there was an association between depressive symptoms and global cognitive functioning similar to prior findings in WEIRD populations. Our results are important for clinicians assessing depressive symptoms in patients in or from Congo or sub-Saharan Africa.

Hippocampal and medial temporal lobe structure atrophy is commonly observed in patients with mild neurocognitive disorders and dementias of various neurodegenerative conditions, with the degree of atrophy in these regions correlating with cognitive performance on memory tasks. This research has been conducted largely in western and educated countries. As cognitive aging, risk factors, clinical course, and neuropathology can differ between individuals of different races and ethnicities, our goal is to determine whether these findings also generalize to patients with suspected dementias living in the Democratic Republic of the Congo (DRC).

Neuroimaging and cognitive data have been collected on 40 subjects with probable dementia from the DRC and 40 age-, education-, and gender-matched controls. Patients were classified into groups based on scores on the Community Screening Instrument and the Alzheimer's Questionnaire. All participants completed the African Neuropsychological Battery. T1 MPRAGE images were acquired on Siemens 1.5T scanner. Freesurfer was used to derive volumes and cortical thickness of medial temporal lobe regions. Volumes of structures were divided by intracranial vault volumes to adjust for head size. T-tests were used to compare hippocampal volumes, entorhinal cortex thickness, and perirhinal cortex thickness between subjects with probable dementia compared to healthy age-, gender-, and education-matched controls. Bivariate correlations were conducted to determine whether the volumes of these structures correlate significantly with learning and memory measures on the ANB.

Results will be determined by the methods described previously.

Results from this study will demonstrate whether structural brain changes commonly seen in individuals with dementia living in western and educated countries also are observed in the DRC. Results will also demonstrate whether these brain changes coincide with the degree of impairments on tasks of memory, and whether these structures can be used to aid in clinical diagnosis of patients with dementia and support the use of the ANB and neuroimaging in clinical detection of dementias in the DRC.