According to the Centers for Disease Control, nearly 6 million Americans are living with Alzheimer’s Disease (AD), a devastating progressive disorder that impairs the parts of the brain that control thought, memory, and language. It can seriously affect a person’s ability to carry out daily activities. AD often starts with mild memory loss but can eventually result in the inability to carry on a conversation or respond to the environment.
Scientists do not fully understand the underlying causes of AD, and while limited treatments are available, there is no known cure.
Novel research from scientists in UW-Madison’s Department of Ophthalmology and Visual Sciences may lead to a new, non-invasive method for the early detection of AD. Thanks to funding from the Wisconsin Alzheimer’s Disease Research Center, Nader Sheibani, PhD and his team of researchers, including Christine Sorenson, PhD, UW-Madison Department of Pediatrics, Tyler Ulland, PhD, UW-Madison Department of Pathology, and Ramin Pahsaie, PhD, Florida Atlantic University, Department of Electrical Engineering and Computer Science, are exploring whether changes to the retinal neurovasculature function and integrity at the back of the eye can serve as an early warning sign for AD.
“Changes related to Alzheimer’s Disease occur in the brain and are not easy to assess,” said Sheibani. “Our team is developing non-invasive ocular vascular imaging as a way to utilize changes in retinal neurovasculature function as a means of predicting the progression and stage of Alzheimer’s Disease.”
In addition to cognitive decline and cortical changes, AD can also be characterized by declines in visual function, ranging from a diminished ability to differentiate among colors to complex object recognition.
“Visual deficit has been reported in the early stages of Alzheimer’s Disease, even before a diagnosis is clearly established,” Sheibani explains. “The effect of AD on visual attention and other higher visual functions can negatively impact a person’s daily activities such as reading, route finding, object localization, and recognition.”
Sheibani says the long-term goal is to advance understanding of the underlying causes of AD-associated visual dysfunction and whether they stem from similar or distinct retinal or cortical abnormalities.
“The objective of this grant is to determine the extent to which retinal neurovascular changes parallel AD etiology in the brain and whether they precede severe cognitive impairment. “
The hypothesis behind Sheibani’s research is that the production and accumulation of the amyloid β (Aβ) in the retina impedes normal ocular neurovascular development and function, as well as inducing swelling in the blood vessels.
“Our rationale is that the identification of Aβ-mediated ocular vascular changes will expedite the development of retinal biomarkers capable of identifying biological changes associated with AD and for tracking the progression of the disease’s severity over time. Ultimately, our findings could result not only in an improved understanding of the pathophysiology of this devastating disease but also in its earlier detection and better management.”