Ambulatory actigraphy correlates with apathy in mild Alzheimer’s disease

Aim: Apathy is one of the most common behavioral symptoms in Alzheimer’s disease (AD). The aim of our study was to assess the relationship between apathy and locomotor activity in mild Alzheimer’s disease (AD). Methods: Thirty AD subjects and fifteen healthy controls were recruited from the Nice Memory Center. Apathy was assessed with the Apathy Inventory (AI). Patients with a score greater than three on the AI caregiver version are considered in this report as having apathy. Locomotor activity was assessed using a wrist-worn actigraph for 75 minutes, during which a neuropsychological and behavioral examination were performed (60 minutes) followed by 15 minutes of free activity. Results: AD patients shown lower motor activity than healthy subjects. AD patients with apathy had lower motor activity than AD patients without apathy. Apathy total score correlated negatively with mean motor activity. Most of the total score correlation was accounted for by correlations between the apathy dimensions lack of initiative and lack of interest, with mean motor activity. Conclusion: Ambulatory actigraphy could be a simple technique to assess apathy objectively as part of routine assessment of AD patients.