Apathy, but not depression, is associated with executive dysfunction in cerebral small vessel disease

Abstract

Objective: To determine the prevalence of apathy and depression in cerebral small vessel disease (SVD), and the relationships between both apathy and depression with cognition. To examine whether apathy is specifically related to impairment in executive functioning and processing speed.

Methods: 196 patients with a clinical lacunar stroke and an anatomically corresponding lacunar infarct on MRI were compared to 300 stroke-free controls. Apathy and depression were measured using the Geriatric Depression Scale, and cognitive functioning was assessed using an SVD cognitive screening tool, the Brief Memory and Executive Test, which measures executive functioning/processing speed and memory/orientation. Path analysis and binary logistic regression were used to assess the relation between apathy, depression and cognitive impairment.

Results: 31 participants with SVD (15.8%) met criteria for apathy only, 23 (11.8%) for both apathy and depression, and 2 (1.0%) for depression only. In the SVD group the presence of apathy was related to global cognition, and specifically to impaired executive functioning/processing speed, but not memory/orientation. The presence of depression was not related to global cognition, impaired executive functioning/processing speed or memory/orientation.

Conclusions: Apathy is a common feature of SVD and is associated with impaired executive functioning/processing speed suggesting the two may share biological mechanisms. Screening for apathy should be considered in SVD, and further work is required to develop and evaluate effective apathy treatment or management in SVD.

Fig 1. Path analysis model.

Path analysis model showing that the magnitude of apathetic symptoms, but not depressive symptoms, is associated with memory/orientation and executive functioning/ processing speed. Premorbid IQ and age were both regressed into the model (not displayed). There was a strong covariance between age and depressive symptoms (β = -.30, p < .001), and between premorbid IQ and executive function/processing speed (β = .35, p < .001) and memory/orientation (β = .16, p = .019). * p < .05; ** p < .005.