Pattern of impaired working memory during major depression.
BACKGROUND
The aim of this study was to assess working memory (WM) in patients with major depressive disorder (MDD), using a robust parametric WM task (the n-back task).


METHODS
Twenty patients with MDD and twenty healthy controls completed a visual version of the paradigm, comprising four levels of task difficulty (i.e. 0-, 1-, 2-, and 3-back). Performance accuracy and reaction time (RT) were measured at each difficulty level.


RESULTS
In comparison with controls, patients with MDD exhibited slower RTs (F((1,38)) = 25.16, p < 0.001), and reduced accuracy (F((1,38)) = 5.93, p < 0.001). There was no diagnosis-specific effect of task difficulty on performance accuracy. However, the faster response to memory (1-3-back) than to shadowing (0-back) tasks observed in controls was not as pronounced in patients.


CONCLUSIONS
These observations support a relatively specific impairment of WM/central executive function in MDD, which may potentially mediate the diverse pattern of cognitive dysfunction noted in MDD. The parametric n-back task is applicable to subjects with MDD and yields results interpretable across the dimensions of task difficulty and performance in controls and patients.
Rose
E J
EJ
National Institute on Drug Abuse, Intramural Research Programme, Baltimore, MD, USA.
Ebmeier
K P
KP
D000328:Adult; D001288:Attention; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000175:diagnosis / Q000523:psychology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D009949:Orientation; D010364:Pattern Recognition, Visual; D010555:Personality Inventory / Q000706:statistics & numerical data; D011594:Psychometrics; D011930:Reaction Time; D012691:Serial Learning; D013223:Statistics as Topic