Diagnostic eye exams and smell tests can identify early
development of Alzheimer’s disease
Orange County, CA - July 28th 2016 - An emerging screening technique presented at the Alzheimer’s Association International Conference (AAIC) in Toronto suggests eye examinations as a means for early detection of this neurological disease. Researchers believe the eye may be used to implicate Alzheimer’s because it’s a part of the central nervous system and is easily accessible compared to the brain.
A noninvasive imaging tool developed and patented by Melanie Campbell, a professor of physics as well as optometry at the University of Waterloo, uses polarized light to illuminate amyloid protein deposits found at the back of patients’ retinas. Researchers believe this detection method will be able to identify the disease decades before cognitive decline occurs in patients.
Another study presented at AAIC indicated a strong association between thinning nerve layers in the retina and poor performance on a cognitive test related to memory, reasoning, and reaction time. In fact, a study released early this month from the Association for Research in Vision and Ophthalmology announced creation of a hyperspectral endoscopy to examine the eye for amyloid plaque.
Current early detection methods are expensive and painful. With Alzheimer’s being difficult to diagnose, doctors consider a combination of late-stage symptoms and diagnostic exams such as spinal taps and PET scans to measure amyloid plaque in the spine and brain, respectively.
But this is not the only identifying biomarker for early detection. There has been noted interest in producing a set of Alzheimer’s checks physicians can perform during routine exams. Findings from two other studies presented at AAIC from Columbia University propose a simple smell test to screen for the degenerative disease.
In both studies, the sample population comprised of individuals in their 60s or older was tasked with pinpointing familiar odors. Results from each study showcased that those who performed inadequately were more likely to have or soon develop cognitive complications.
Dr. William Kreisl, a neurologist from Columbia University that led one of the studies, explained that his team used the University of Pennsylvania Smell Identification Test (UPSIT), a scratch and sniff scent card test using familiar odors such as cinnamon and chocolate. Kreisl said its success in predicting memory decline had the same level of precision as PET scans or spinal taps. The other study followed 397 people over a four year period and found the odor test could accurately foresee which participants were likely to develop dementia.
Since odor identification insufficiency can stem from a variety of causes, such as Parkinson’s disease, smoking, and head injuries, consideration of several biomarkers can give physicians a better grasp on the diagnosis. Although limited by the lack of drugs that slow or stop the progression of the disease, early detection remains important. Not only does it provide patients with time to make necessary arrangements, this aspect of Alzheimer’s research will be critical while a cure for the disease is developed.
