Cognitive Fatigue As a Moderator of the Relationship Between Depression and Visual Memory in MS

Background: Previous research has found that depression negatively impacts visual memory, and that visual learning and memory is usually impaired in MS. Cognitive fatigue usually negatively impacts performance on cognitive testing, especially in MS. This study looked at the relationship between visual memory and depression in MS, and to determine how cognitive fatigue affects this relationship.

Objectives: To determine the relationship between visual memory, cognitive fatigue, and depression specifically in MS.

Methods: This research was conducted at the MS Center of Holy Name Medical Center in Teaneck, NJ. N=117 patients with definite MS who had participated in neuropsychological testing were used in the analyses. From a longer battery, the Hospital Anxiety and Depression Scale depression subscale (HADS D) was selected to measure self-reported depressive symptoms. Cognitive fatigue was measured using The Fatigue Scale for Motor and Cognitive Functions (FSMC) cognitive subscale, a well-validated measure of cognitive fatigue in MS.  Patients were also administered the Brief Visuospatial Memory Test-Revised (BVMT-R), a neuropsychological measure of visual learning and memory. A moderation analysis was conducted looking at the relationship between the HADS D and the BVMT with the FSMC cognitive subscale as a moderator.

Results: The FSMC cognitive subscale moderated the relationship between the HADS D Total Score and BVMT Total Score b = -0.80, 95% CI [-1.42, -0.17], t = -2.51, p < .05.

Conclusions: Cognitive fatigue moderates the relationship between depression and visual memory in MS. There is a significant relationship between depression and visual memory only at high levels of cognitive fatigue, and not at moderate or low levels.