Assessment of the Autonomic Response in Alzheimer's Patients During the Execution of Memory Tasks: A Functional Thermal Imaging Study

Abstract

Background: Alzheimer's disease (AD) is a form of dementia characterized by failure of memory that becomes more severe with the progression of the disease. The Free and Cued Selective Reminding Test (FCSRT) is a clinical test used to evaluate such a deficit. However, since the cognitive performances could depend also on the psychophysiological state of the individual, it is important to monitor that state through the peripheral autonomic activity during the execution of the test. Thermal infrared imaging has been used for this kind of assessment in order to preserve the free and unbiased interaction between doctor and patient, thanks to the contactless features of the technique.

Objective: To investigate whether the variation of facial temperature parameters during the FCSRT is indicative of different autonomic states in the early AD with respect to healthy controls (HC).

Results: At a group level, a greater sympathetic activity for the HC with respect to AD during the execution of the test was found, indicative of a suppression of anxiety associated with the performances of the FCSRT in AD patients.

Conclusion: These results indicate that AD and HC may present different autonomic activity associated with the execution of a cognitive task, thus suggesting a different modulation of high-cognition and emotion network.

Keywords: Alzheimer's disease; FCSRT; autonomic response; memory deficit; thermal imaging; visuospatial deficit..