Post-Stroke Depression, Apathy and Alexithymia

Introduction: Several behavioural changes can occur as a consequence of stroke. A large number of studies have evaluated the frequency and severity of post-stroke depression, apathy and alexithymia that result from stroke, however the published data is contradictory. Aim: The aim of this article is to present a literature review of the concepts of depression, apathy and alexithymia and post-stroke neuroanatomical findings that support these psychopathological observations. Methods: Literature review of selected articles and books deemed relevant by the authors, using Medline/Pubmed database with the combination of the following key-words: "stroke", "apathy", "alexithymia", "depression", published between 1973 and 2013. References of the selected articles and books were also considered. Results and Conclusions: After stroke, many patients are left with variable levels of disability, resulting in a mourning process, and this emotional response is thought to be a normative one to post-stroke problems. It has been understood that the depressive dimension is associated with left frontal lobe functioning (the so-called left frontal lobe theory), whereas the apathetic dimension is associated with the basal ganglia. The rate of apathy is lower in patients without previous cerebrovascular disease; the rate of 'pure' apathy (without concomitant depression) is twice as frequent as the rate of 'pure' depression (without concomitant apathy). Apathetic patients are more frequently and severely depressed and cognitively impaired in comparison to nonapathetic patients. The mechanisms underlying reduced emotional consciousness and emotional blunting following stroke of the MCA are still poorly understood. Apathy and adynamia can be attributed to lesions in the insula and basal ganglia, however reduced emotional awareness can occur as a consequence of changes in the cerebral activity of distant regions. Functional and structural alterations in the anterior cingulate cortex have been implicated with the mechanisms of alexithymia. The right hemisphere seems to be superior in the processing and organization of emotional experience when compared with the left hemisphere. Acquired alexithymia can occur as a consequence of lesions in the right MCA territory and this can be significant as it alters the traditional presentation of a depressive episode. Future research should evaluate if these differences in the lesion localization and their influence in functional recovery can, separately or together, originate different patterns of response to treatment.