In a new study published in the journal Neurobiology of Aging, UC San Diego School of Medicine suggests that measuring the speed of pupil dilation while cognitive testing is being performed may be an alternative, non-invasive, and economical method Affordable screening test that can detect those at higher risk of Alzheimer's disease before they develop. Cognitive decline.
Researchers studied the pathology of Alzheimer's disease and focused on two main factors that contribute to the disease - the accumulation of protein plaques in the brain (called amyloid beta) and tau protein tangles. Both factors are associated with cognitive impairment.
Pupillary reaction may indicate AD risk
The study shows how pupils respond to specific neurons in the brain called the locus coeruleus (LC), which are involved in cognitive function and arousal. One of the earliest biomarkers of AD, the protein tau, first appears in the locus coeruleus. Tau tangles are more associated with cognitive abilities than amyloid beta.
LC stimulates pupillary responses, such as changing the diameter of the eye's pupil during cognitive tasks. When brain tasks become more difficult or complex, a person's pupils become larger. In a previous study, researchers reported that people with mild cognitive impairment, a precursor to Alzheimer's disease, showed greater pupil dilation than people without any cognitive problems.
In this study, however, the researchers wanted to find an association between the pupil dilation response and identified AD risk genes.
Given the link between pupillary response, LC, and tau protein, and the association between pupillary response and the AD polygenic risk score (a summary of factors that determine an individual's inherited risk for AD), these results are a proof-of-concept for measuring pupils during cognitive tasks. Response could be another screening tool to detect Alzheimer's disease before symptoms appear.
Still no predictive test for Alzheimer's
Alzheimer's disease is a global health problem. In the United States, it is the sixth leading cause of death, with approximately 5.5 million Americans living with the disease.
Currently, there is no cure for Alzheimer's disease, and there are no predictive tests available. Diagnosis of this disorder is usually made through clinical consultation, which may be derived from history, medical interview, signs and symptoms, and assessment.
Testing including scans, blood and urine samples, and psychiatric evaluations can help rule out other health conditions with similar symptoms. The only way to confirm is when the patient dies and the brain tissue is examined.
Noble testing is less invasive, more targeted and easy to administer.
Identifying specific genes associated with pupillary response factors may improve understanding of LC-NE system function and the genetic mediators that influence the risk of MCI (mild cognitive impairment) and AD (Alzheimer's disease).
