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it Is known that Alzheimer’s disease (AD) begins to alter and damage the brain years, even decades, before the first symptoms appear, making its early identification is paramount to slow its progression.
Now, a study published in “Neurobiology of Aging”, scientists of the Faculty of Medicine of the University of California, San Diego (USA) ensure that the speed with which dilates the pupil when a person is performing cognitive tests may be a method of low cost and non-invasive to help in the detection of individuals with increased genetic risk of alzheimer’s disease before the start of the cognitive impairment.
In recent years, researchers have turned their attention to two causal factors or contributory : the buildup of plaque proteins in the brain called beta amyloid and tangles of a protein called tau. Both have been linked to damage and kill neurons, resulting in progressive cognitive dysfunction.
The new study focuses on the responses pupillary that are driven by the locus coeruleus (LC), a group of neurons in the brainstem involved in the regulation of arousal and in the modulation of cognitive function.
Tau, a biomarker known most ancient to the disease of alzheimer’s disease, appears for the first time in the LC, and is more associated with the cognition that the protein beta-amyloid. The LC drives the pupillary responses (the diameter changing of the pupils of the eyes) during cognitive tasks. (The pupils become larger the more difficult is the task of the brain).
The results are a proof-of-concept to assess the pupillary responses during cognitive tasks could be another screening tool to detect alzheimer’s before symptoms appear
In a previously published work, the researchers led by William S. Kremen and Carol E. Franz, they saw that the adults with mild cognitive impairment, often a precursor to Alzheimer’s disease, showed a pupil dilation and a cognitive effort higher than the individuals as cognitively normal, even if both groups produced equivalent results.
Now, in this latest article, linking the responses of pupil dilation with risk genes for AD have been identified.
“Because of the evidence that links the responses pupillary, LC and tau, and the association between pupillary response and the risk scores of polygenic modifiers of alzheimer’s disease (an accounting aggregate of the factors to determine the risk of AD is inherited from an individual), these results are a proof-of-concept to assess the pupillary responses during cognitive tasks could be another screening tool to detect alzheimer’s before symptoms appear,” concludes Kremen.
