Eye scanning to help identify Alzheimer's symptoms

Brain scientists at Sunnybrook are using an innovative eye-tracking technology to test memory, attention and behaviour in Alzheimer's patients, to help them better identify, differentiate and treat symptoms.

In a current ongoing study, the researchers are measuring visual attention scanning and patterns towards competing visual stimuli in real time, to successfully distinguish between apathy (loss of interest and motivation) and depression in patients with Alzheimer's disease (AD).

"Apathy and depression have distinct neurobiology and treatments, and to complicate matters, some treatments for depression may exacerbate symptoms of apathy," explains Dr. Krista Lanctôt, a co-investigator of the study and a neuropsychopharmacologist at Sunnybrook. "These symptoms often contribute to decline in quality of life for patients and their caregivers, and they are often difficult to assess in particular as cognition deteriorates."

"Better methods of differentiation are necessary to guide clinicians in determining the most beneficial treatment course," says Dr. Nathan Herrmann, co-investigator and head of Geriatric Psychiatry at Sunnybrook.

Applied to the AD population for the first time, this technology allowed the researchers to explore a way to assess symptoms of apathy and depression that does not rely on patient verbal skills or caregiver reports.

"This approach measures where the patient's gaze is focused and the preference for sad versus social or neutral images presented on a screen instead of relying on the patient to recognize and remember how they felt at different times," says Sarah Chau, lead author of the study abstract, research student at Sunnybrook, and PhD candidate in the department of Pharmacology/Toxicology at University of Toronto.

Preliminary findings suggest that interest in social stimuli using this technology can distinguish AD patients with different behavioural disturbances and is associated with severity of apathy. There was a significant difference in the number of fixations on social images between groups, specifically apathetic patients were less interested in social images compared with those without neuropsychiatric symptoms.