Visual Search Efficiency in Mild Cognitive Impairment and Alzheimer’s Disease: An Eye Movement Study

Article type: Research Article

Authors: Pereira, Marta Luísa Gonçalves de Freitas^{a; *} | Camargo, Marina von Zuben de Arruda^a | Bellan, Ariella Fornachari Ribeiro^a | Tahira, Ana Carolina^{a; b} | dos Santos, Bernardo^c | dos Santos, Jéssica^d | Machado-Lima, Ariane^d | Nunes, Fátima L.S.^d | Forlenza, Orestes Vicente^a

Affiliations: [a] Laboratório de Neurociências (LIM-27), Departamento e Instituto de Psiquiatria HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil | [b] LIM-23, Departamento e Instituto de Psiquiatria HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil | [c] Escola de Enfermagem, Universidade de São Paulo, São Paulo, Brazil | [d] Laboratório de Aplicações de Informática em Saúde, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, SP, Brazil

Correspondence: [*] Correspondence to: Marta Luísa Gonçalves de Freitas Pereira, Laboratory of Neuroscience (LIM-27), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, Rua Dr. Ovídio Pires de Campos 785, CEAPESQ, third floor, room 2, 05403-010 São Paulo, SP - Brazil. E-mail: [email protected].

Abstract: Background:Visual search abilities are essential to everyday life activities and are known to be affected in Alzheimer’s disease (AD). However, little is known about visual search efficiency in mild cognitive impairment (MCI), a transitive state between normal aging and dementia. Eye movement studies and machine learning methods have been recently used to detect oculomotor impairments in individuals with dementia. Objective:The aim of the present study is to investigate the association between eye movement metrics and visual search impairment in MCI and AD. Methods:127 participants were tested: 43 healthy controls, 51 with MCI, and 33 with AD. They completed an eyetracking visual search task where they had to find a previously seen target stimulus among distractors. Results:Both patient groups made more fixations on the screen when searching for a target, with longer duration than controls. MCI and AD fixated the distractors more often and for a longer period of time than the target. Healthy controls were quicker and made less fixations when scanning the stimuli for the first time. Machine-learning methods were able to distinguish between controls and AD subjects and to identify MCI subjects with a similar oculomotor profile to AD with a good accuracy. Conclusion:Results showed that eye movement metrics are useful for identifying visual search impairments in MCI and AD, with possible implications in the early identification of individuals with high-risk of developing AD.

Keywords: Alzheimer’s disease, eye movements, eyetracking, machine learning, mild cognitive impairment, visual attention, visual impairments, visual search

DOI: 10.3233/JAD-190690

Journal: Journal of Alzheimer's Disease, vol. 75, no. 1, pp. 261-275, 2020