Apathy and Attentional Biases in Alzheimer’s Disease

Article type: Research Article

Authors: Chau, Sarah A.^{a; b} | Chung, Jonathan^{c; d} | Herrmann, Nathan^{a; e} | Eizenman, Moshe^{c; d; f} | Lanctôt, Krista L.^{a; b; e; *}

Affiliations: [a] Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada | [b] Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada | [c] Institute of Biomaterials and Biomedical Engineering, University of Toronto, ON, Canada | [d] Department of Electrical and Computer Engineering, University of Toronto, ON, Canada | [e] Department of Psychiatry, University of Toronto, Toronto, ON, Canada | [f] Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada

Correspondence: [*] Correspondence to: Krista Lanctôt, Neuropsychopharmacology Research Group, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Suite FG08, Toronto, ON M4 N 3M5, Canada. Fax: +1 416 480 6022; Email: Krista.Lanctot@sunnybrook.ca.

Abstract: Background:Apathy, one of the most prevalent neuropsychiatric symptoms in Alzheimer’s disease (AD), can be difficult to assess as cognition deteriorates. There is a need for more objective assessments that do not rely on patient insight, communicative capacities, or caregiver observation. Objective:We measured visual scanning behavior, using an eye-tracker, to explore attentional bias in the presence of competing stimuli to assess apathy in AD patients. Methods:Mild-to-moderate AD patients (Standardized Mini-Mental Status Examination, sMMSE >10) were assessed for apathy (Neuropsychiatric Inventory [NPI] apathy, Apathy Evaluation Scale [AES]). Participants were presented with 16 slides, each containing 4 images of different emotional themes (2 neutral, 1 social, 1 dysphoric). The duration of time spent, and fixation frequency on images were measured. Results:Of the 36 AD patients (14 females, age = 78.2±7.8, sMMSE = 22.4±3.5) included, 17 had significant apathy (based on NPI apathy ≥4) and 19 did not. These groups had comparable age and sMMSE. Repeated-measures analysis of covariance models, controlling for total NPI, showed group (apathetic versus non-apathetic) by image (social versus dysphoric) interactions for duration (F1,32 = 4.31, p = 0.046) and fixation frequency (F1,32 = 11.34, p = 0.002). Apathetic patients demonstrated reduced duration and fixation frequency on social images compared with non-apathetic patients. Additionally, linear regression models suggest that more severe apathy predicted decreasing fixation frequency on social images (R2 = 0.26, Adjusted R2 = 0.19, F3,32 = 3.65, p = 0.023). Conclusion:These results suggest that diminished attentional bias toward social-themed stimuli is a marker of apathy in AD. Measurements of visual scanning behavior may have the potential to predict and monitor treatment response in apathy.

Keywords: Alzheimer’s disease, apathy, attention, cognition, eye movements

DOI: 10.3233/JAD-151026

Journal: Journal of Alzheimer's Disease, vol. 51, no. 3, pp. 837-846, 2016