Post-stroke apathy: A case series investigation of neuropsychological and lesion characteristics

Apathy is a multi-dimensional syndrome associated with reduced initiation, executive function and emotion toward goal-directed behaviour. Affecting ~30% of stroke patients, apathy can negatively impact rehabilitation outcomes and increase caregiver burden. However, relatively little is known about the multi-dimensional nature of post-stroke apathy and whether these dimensions map onto neuropsychological and neuroanatomical correlates. The present study aimed to address this question in a case series of stroke patients with apathy. 65 patients with acute stroke were assessed on a comprehensive battery of neuropsychological tasks and 12 patients were identified as having clinically significant apathy on one or more domains on the Dimensional Apathy Scale. Individual scores were compared to a group of healthy controls and normative data where available. Lesion mapping was completed from clinical CT and MRI scans to characterise the extent and locations of each patient's lesion. All participants performed significantly poorer than controls on one or more tasks. Difficulties with inhibition were observed across all dimensions. Prospective memory deficits were also common, while speed and social cognition were only reduced in initiation and emotional apathy, respectively. Verbal fluency was not impaired in any of the patients, despite previously established relationships with apathy. Lesions were predominantly located in right subcortical regions, with some additional frontal, temporal and cerebellar/brainstem involvement. There was substantial overlap in lesion locations within and between dimensions, such that similar apathy symptoms occurred in patients with very different lesion sites. Overall, our results suggest that neuropsychological and lesion profiles of apathy in stroke patients may be more complex and heterogenous than in neurodegenerative disease, possibly due to functional changes occurring beyond the lesion site.