Clinical profiles of apathy in dementia
What is it about?
Apathy (i.e., the reduction of behaviors directed towards a goal) is highly frequent in dementia, especially in behavioral variant frontotemporal dementia (bvFTD), and presents a lot of debilitating consequences for patients and their caregivers. Our objective was to disentangle different clinical profiles of apathy among these patients using a technique of data-driven clustering from validated measures of apathy forms. Thanks to behavioral measures obtained in a naturalistic context (observation of patients' behavior in a waiting room) combined with MRI neuroimaging of patients' brain, we have been able to precisely describe the profiles of identified clusters (or subgroups) of patients. One subgroup, which presented the smallest pattern of brain damage (including in particular the orbitofrontal cortex) with a right asymmetry, was characterized by a difficulty to self-initiate goal-directed behaviors but could initiate them with the external attribution of a goal-directed activity (i.e. filling a questionnaire). In two other subgroups showing more diffuse bilateral brain atrophies extending to lateral prefrontal cortex, we observed more difficulty to focus on goal-management and even with the external attribution of a goal, these patients did not increase their production of goal-directed behaviors.
Why is it important?
These findings have implications for clinicians in a perspective of precision medicine as they could contribute to personalize treatments of apathy. Until now, treatments for apathy have not been effective. One possible reason to explain the poor efficiency of current treatments may be that several different mechanisms contribute to reduce goal-directed behaviors and if the mechanisms underlying apathy are qualitatively different, they are likely to require different therapeutic interventions. The identification of a profile in which initiation of goal-directed behaviors can be maintained with external guidance is particularly interesting for the purpose of testing new behavioral interventions.