Evidence of impaired facial emotion recognition in mild Alzheimer’s disease: A mathematical approach and application

Objectives: The first objective of this paper is to show the improved binary outcomes resulting from using MARIE as a diagnostic instrument that allows valid and reliable visual recognition of facial emotional expressions (VRFEE) in an objective and quantitative manner. The second objective is to demonstrate mathematical modeling of binary responses that allow the measurement of categorical dimension, sensitivity, camber, equilibrium points, transition thresholds, etc. The final objective is to illustrate the use of this test for 1) testing a homogeneous sample of healthy young participants; and 2) applying this method to a sample of 12 participants with early Alz-heimer disease compared to a matched control sample of healthy elderly participants. Design: Transforming the binary outcomes of MARIE in mathematical variables (experiment 1), allowing verification of a disorder of VRFEE in early Alzheimer’s disease (experiment 2). Measures: Comparison of numerical variables and graphic representations of both samples. Results: The objective measurement of VRFEE is possible in a healthy population. The application of this methodology to a pathological population is also made possible. The results support the current literature. Conclusion: The combination of the mathematical method with the diagnostic instrument MARIE shows its power and ease of use in clinical practice and research. Its application in many clinical conditions and in clinical research can be useful for understanding brain function. This method improves 1) the inter-examiner comparison and standardizes the quantification of VRFEE for use by multiple researchers; 2) the follow-up of a sample over time; 3) the comparison of two or more samples. This method is already available in clinical work for refining the diagnosis of Alzheimer’s Disease (AD) in our department.