Major depressive disorder (MDD) is characterized by symptoms such as depressed mood and loss of interests, but also accompanies disruptions to cognition, sensation, and perception. New research published in BMC Psychiatry showed that patients with MDD performed poorer on visual memory tasks and have higher levels of pattern glare compared to a control group without MDD.
People with MDD can demonstrate poorer performance on tests of memory, information processing, and attention compared to those without MDD. However, memory impairment is one of the most common cognitive disruptions experienced by those with MDD.
“Previous clinical studies have established that patients with acute depression show deficits in various memory domains, including but not limited to visual memory, visuospatial working memory, verbal memory, immediate memory, and delayed memory,” wrote study author Min Wang and colleagues. “In addition, memory impairment not only affects function during acute episodes of the illness, as recent evidence suggests that cognitive dysfunction persists following symptomatic remission.”
Researchers were interested in comparing visual memory and pattern glare (visual distortions and/or physical discomfort form viewing repetitive striped patterns) levels between people with and without MDD. For this study, researchers recruited 62 inpatients with MDD from the Mental Health Centre of West China Hospital and 49 people without MDD from the community. All participants completed tests of visual memory and pattern glare.
The MDD patient group and control group did not differ on any demographic variable measured (age, gender, education). In general, those with MDD had lower visual memory task scores compared to the no-MDD control group. MDD patients also had higher pattern glare scores overall than the control group.
“One with elevated pattern glare will experience visual perceptual or physical discomfort when viewing repetitive stripes. Distractions when representing information can damage storage mediated by the visual cortex and lead to disruptions in working memory. Therefore, individuals with elevated pattern glare may have an accompanying visual memory impairment in conditions where the brain’s essential function is coordinated and stable.”
The authors cite some limitations to this work including the relatively small sample size and the inclusion of only currently unmedicated MDD patients. Future work can use a longitudinal approach to assess the impact of MDD on visual memory over time and with medication use.
The study, “The pattern glare and visual memory are disrupted in patients with major depressive disorder“, was authored by Min Wang, Xiongwei Qi, Xiao Yang, Huanhuan Fan, Yikai Dou, Wanjun Guo, Qiang Wang, Eric Chen, Tao Li, and Xiaohong Ma.
