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J Alzheimers Dis. 2016;51(3):837-46. doi: 10.3233/JAD-151026.

Apathy and Attentional Biases in Alzheimer's Disease.

Author information

1
Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada.
2
Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada.
3
Institute of Biomaterials and Biomedical Engineering, University of Toronto, ON, Canada.
4
Department of Electrical and Computer Engineering, University of Toronto, ON, Canada.
5
Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
6
Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada.

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 (F(1,32) = 4.31, p = 0.046) and fixation frequency (F(1,32) = 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, F(3,32) = 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

PMID:
26890774
DOI:
10.3233/JAD-151026
[Indexed for MEDLINE]

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