Researchers have found in a new study that pupil dilation could serve as an indicator of attention and mental effort in individuals with mild cognitive impairment, suggesting its potential as a simple, noninvasive marker of early cognitive changes. The study was published in the Alzheimer’s & Dementia journal by Alina Z. and colleagues.Pupil dilation can be considered a response to cognitively demanding stimuli that are salient in nature. This can be considered beneficial in a population where cognitive testing might be limited. The results of the study have shown that a correlation exists between pupil dilation and attentional control in all three groups: young adults, elderly subjects, and patients with mild cognitive impairment.The study included an assessment of pupil dilations in three different groups of participants: young adults, older adults, and those suffering from mild cognitive impairments. Pupil dilations were monitored in two standardized cognitive tests, namely, an oddball test that focuses on attention allocation, and a Simon test that focuses on cognitive effort. These tests provided a comprehensive assessment of cognitive attention and cognitive effort. Cognitive attention and cognitive effort are two important cognitive processes that can be comprehensively evaluated through these two tests.Key findings:An evaluation of the pupil dilations of three different groups of participants, namely young adults, older adults, and those experiencing mild cognitive impairments, was also included in this study. Pupil dilations were monitored for two standardized cognitive tests, namely, an oddball test that measures attention allocation and a Simon test that measures cognitive effort. These two tests comprehensively evaluate two important cognitive processes, namely cognitive attention and cognitive effort.The inclusion of pupil dilation measurement in clinical and research practices may aid in the early detection and monitoring of cognitive decline. This is due to its sensitivity to attention and executive control. This offers a multi-dimensional approach to brain functioning. Further research is required to standardize the measurement and validate it for use in a wider clinical population, including those suffering from neurodegenerative diseases.Pupil dilation acts as a reliable non-invasive indicator of attentional processes and cognitive efforts. It provides an effective tool for the assessment of cognitive functions in patients with mild cognitive impairment and aging populations.Reference:Zhunussova A, Loane C, Kurt E, et al. Pupil dilation as a marker of attention/effort in aging and mild cognitive impairment. Alzheimer’s Dement. 2026;22:e71180. https://doi.org/10.1002/alz.71180