Abstract
Objective Compared to individuals without cognitive impairment (CI), those with CI exhibit differences in both basic oculomotor functions and complex viewing behaviors. However, the characteristics of the differences and how those differences relate to various cognitive functions have not been widely explored. In this work we aimed to quantify those differences and assess general cognitive impairment and specific cognitive functions.
Methods A validated passive viewing memory test with eyetracking was administered to 348 healthy controls and CI individuals. Spatial, temporal, semantic, and other composite features were extracted from the estimated eye-gaze locations on the corresponding pictures displayed during the test. These features were then used to characterize viewing patterns, classify cognitive impairment, and estimate scores in various neuropsychological tests using machine learning.
Results Statistically significant differences in spatial, spatiotemporal, and semantic features were found between healthy controls and individuals with CI. CI group spent more time gazing at the center of the image, looked at more regions of interest (ROI), transitioned less often between ROI yet in a more unpredictable manner, and had different semantic preferences. A combination of these features achieved an area under the receiver-operator curve of 0.78 in differentiating CI individuals from controls. Statistically significant correlations were identified between actual and estimated MoCA scores and other neuropsychological tests.
Conclusion Evaluating visual exploration behaviors provided quantitative and systematic evidence of differences in CI individuals, leading to an improved approach for passive cognitive impairment screening.
Significance The proposed passive, accessible, and scalable approach could help with earlier detection and a better understanding of cognitive impairment.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This research was supported by funding from the James M. Cox Foundation, the Goizueta Foundation and the Goizueta Alzheimer Disease Research Center at Emory University (P50 AG025688), and the Emory Healthy Brain Study (R01 AG070937).
Author Declarations
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Ethics committee/IRB of Emory University gave ethical approval for this work
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Footnotes
This research was supported by funding from the James M. Cox Foundation, the Goizueta Foundation and the Goizueta Alzheimer Disease Research Center at Emory University (P50 AG025688), and the Emory Healthy Brain Study (R01 AG070937).
Data Availability
Raw data cannot be shared publicly since it contains personal identifiable information (video recordings of participants' faces). Although participants agreed to be recorded for purposes of the work, there are restrictions in place for the release of PII. Additionally, due to the sensitive nature of the data that we collect, Certificates of Confidentiality are in place to prohibit disclosure of identifying information