Alzheimer's disease in the pupil : pupillometry as a biomarker of cognitive processing in Alzheimer's disease

Alzheimer’s disease (AD) is a neurodegenerative disorder and a major public health issue that is rising at an alarming rate as the population ages. Despite all the efforts to develop effective pharmacological therapies, AD is currently incurable. In light of the lack of efficient treatment, a main focus in AD management is the identification of individuals who are at risk of AD; this is to predict disease onset and, ideally, to maintain cognitive and functional abilities before substantial neurological decline. Two main biomarkers can be used to reflect the onset of AD, namely, the presence of amyloid-β (Aβ) and tau pathology in cerebrospinal fluid (CSF) and the reduced volume of the hippocampus as can be observed on structural magnetic resonance imaging (MRI). While these biomarkers are widely used to detect AD, there is still need to identify better markers of the disease, ideally, a noninvasive (as CSF tests require medical intervention) and inexpensive test (as MRI is typically expensive). To tackle this challenge, we investigate whether pupil dilation can offer a noninvasive and inexpensive marker of cognitive decline in AD. More specifically, we offer a case study in which we evaluate whether pupil dilation can index cognitive effort in a patient with AD. By doing so, we aim to reveal whether pupil dilation has the potential to mirror cognitive processing in AD.