title: Exploring Visual Selective Attention towards Novel Stimuli in Alzheimer's Disease Patients.
abstract: BACKGROUND
  Alzheimer's disease (AD) is associated with selective attention impairments, which could contribute to cognitive and functional deficits. Selective attention can be explored through examination of novelty preference.
  
  
  OBJECTIVE
  In this study, we quantified novelty preference in AD patients by measuring visual scanning behaviour using an eye tracking paradigm.
  
  
  METHODS
  Mild-to-moderate AD patients and elderly controls viewed slides containing novel and repeated images simultaneously. The outcome measure was time spent on specific images, with novelty preference defined by greater relative fixation time (RFT) on novel versus repeated images. Cognitive status (Standardized Mini-Mental State Examination, SMMSE) and attention (Digit Span, DS) were also measured.
  
  
  RESULTS
  AD patients (age 79.2 ± 6.7 years, SMMSE 22.2 ± 4.0, n = 41) and controls (age 76.2 ± 6.4 years, SMMSE 28.1 ± 2.0, n = 24) were similar in age, education and sex. Compared with controls, AD patients had lower RFT on novel than on repeated images (F1,63 = 11.18, p = 0.001). Further, reduced RFT was associated with lower scores on SMMSE (r63 = 0.288, p = 0.020) and DS (r63 = 0.269, p = 0.030). Within individuals, novelty preference was detected in 92.3% of patients and in 100% of controls.
  
  
  CONCLUSIONS
  These findings suggest that novelty preference, measured by visual scanning behaviour, can differentiate cognitively healthy and impaired people and may offer a nonverbal, less cognitively demanding method of assessing selective attention.
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ont., Canada; Departments of Pharmacology and Toxicology, University of Toronto, Toronto, Ont., Canada.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Chau
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ont., Canada; Departments of Psychiatry, University of Toronto, Toronto, Ont., Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Herrmann
authors.affiliation: Departments of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ont., Canada; Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ont., Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ont., Canada.
authors.forename: Moshe
authors.initials: M
authors.lastname: Eizenman
authors.affiliation: Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ont., Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ont., Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chung
authors.affiliation: Neuropsychopharmacology Research Group, Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ont., Canada; Departments of Pharmacology and Toxicology, University of Toronto, Toronto, Ont., Canada; Departments of Psychiatry, University of Toronto, Toronto, Ont., Canada.
authors.forename: Krista L
authors.initials: KL
authors.lastname: Lanctôt
keywords: Alzheimer's disease; Attention dysfunction/cognition; Novelty preference; Selective attention; Visual attention; Visual scanning