Examination of the pupils can determine the risk of Alzheimer's early
Alzheimer's damages and changes the brain long before the first symptoms appear. Examination of the eyes together with cognitive tests could determine the risk of Alzheimer's early.
A recent study by the University of California San Diego School of Medicine has now found that including pupil movement together with cognitive tests can lead to an improved determination of Alzheimer's risk. The results of the study were published in the English-language journal "Neurobiology of Aging".
Alzheimer's damages the brain long before the first symptoms appear
Alzheimer's disease changes and damages the brain years or even decades before the first symptoms appear. Therefore, early detection of the risk of Alzheimer's is of the utmost importance. By measuring how quickly a person's pupil dilates while doing cognitive tests, an increased genetic risk for Alzheimer's can be identified long before the cognitive decline begins.
Why can the pupil reaction indicate Alzheimer's?
When examining the pathology of Alzheimer's, attention has so far focused primarily on two causal or contributing factors: the accumulation of protein plaques in the brain (amyloid beta) and clumping of a protein (tau). Both factors have previously been linked to neuron damage and killing, leading to progressive cognitive dysfunction, the researchers report.
The new study focused on pupil responses that are controlled by the locus coeruleus, a cluster of neurons in the brain stem that helps regulate arousal and modulate cognitive function. Tau is the earliest known biomarker for Alzheimer's. Dew first appears in the locus coeruleus and is more cognitive than amyloid beta, the researchers explain. The locus coeruleus controls the pupil reaction, the changing diameter of the pupils, while the participants are performing cognitive tasks. In a previously published research report, it was reported that adults with mild cognitive impairment showed greater pupil dilation and cognitive exertion than cognitively normal people, even though both groups achieved equivalent results.
Measuring pupil reactions as a reliable screening tool?
It is crucial that the researchers linked the pupil dilation reactions with identified risk genes for Alzheimer's in the latest study. Given the evidence between pupil responses, locus coeruleus, and tau, and the association between pupil responses and polygenic risk assessments for Alzheimer's (an aggregate calculation of the factors used to determine a person's inherited risk for Alzheimer's), the results show that measuring pupil responses during cognitive tasks is another The screening tool can be used to detect Alzheimer's before the first symptoms appear, the researchers explain. (as)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
- William S. Kremen, Matthew S. Panizzon, Jeremy A. Elman, Eric L. Granholm, Ole A. Andreassen et al .: Pupillary dilation responses as a midlife indicator of risk for Alzheimer's Disease: Association with Alzheimer's disease polygenic risk, in Neurobiology of Aging (Query: 09/11/2019), Neurobiology of Aging