Characterization of apathy in persons with frontotemporal dementia and the impact on family caregivers.

This study characterized daytime activity and apathy in patients with behavioral variant frontotemporal dementia (bvFTD) and semantic dementia (SD) and their family caregivers. Twenty-two patient-caregiver dyads were enrolled: 13 bvFTD and 9 SD. Data were collected on behavior and movement. Patients and caregivers wore Actiwatches for 2 weeks to record activity. We predicted that bvFTD patients would show greater caregiver report of apathy and less daytime activity compared with patients diagnosed with SD. Patients with bvFTD spent 25% of their day immobile, whereas patients with SD spent 16% of their day inactive. BvFTD caregivers spent 11% of their day immobile and SD caregivers were immobile 9% of their day. Apathy was present in all of the patients with bvFTD and in all but one patient with SD; the severity of apathy was greater in bvFTD compared with SD. Apathy correlated with caregiver emotional distress in both groups. In conclusion, apathy has been defined as a condition of diminished motivation that is difficult to operationalize. Among patients with frontotemporal dementia, apathy was associated with lower levels of activity, greater number of bouts of immobility, and longer immobility bout duration. Apathy and diminished daytime activity appeared to have an impact on the caregiver. Objective measures of behavioral output may help in formulation of a more precise definition of apathy.