Uncorrected Author Proof Journal of Alzheimer’s Disease xx (20xx) x–xx DOI 10.3233/JAD-190981 IOS Press 1 Visual Search in Behavioral Variant Frontotemporal Dementia 1 2 Amanda Douglass a,b,∗ , Mark Walterfang c,d,e , Dennis Velakoulis c,d and Larry Abel b 3 a Optometry, School of Medicine, Deakin University, Waurn Ponds, Australia 4 b Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia 5 c Department of Psychiatry, The University of Melbourne, Melbourne, Australia 6 d Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, Australia 7 e Florey Institute of Neuroscience and Mental Health, Melbourne, Australia 8 Accepted 2 October 2019 Abstract. 9 Background: Changes to visual search have shown specific patterns in a number of dementia subtypes. The cortical regions involved in the control of visual search overlap with the regions affected in behavioral variant frontotemporal dementia (bvFTD). Previous literature has examined visual search in bvFTD with smaller array sizes. 10 11 12 Objective: To examine the pattern of behavior shown by bvFTD patients while undertaking visual search in the presence of larger numbers of distractors to model increased cognitive load. 13 14 Methods: 15 bvFTD and 17 control participants undertook three visual search tasks: color, orientation, and conjunction searches. A wide range of array sizes was used, from 16 to 100 items arranged as a square. Behavior was quantified using accuracy, response time, and eye movements. 15 16 17 Results: bvFTD participants displayed a reduction in accuracy and an increased response time across all task types. bvFTD participants displayed an increase in number of objects examined and number of fixations made for color and conjunction tasks. Fixation duration was increased for orientation and conjunction (the more difficult tasks) but not color search. Results indicated the increase in fixation duration to be due to an increased intercept, with no significant difference in slope for the different tasks. 18 19 20 21 22 Conclusion: bvFTD participants display a pattern of visual search behavior consisting of a decrease in accuracy, an increase in response time, and a corresponding increase in the number and length of eye movements made during visual search. The pattern seen corresponds to studies of frontal lobe damage, while differing in pattern from that seen in a range of other cognitive conditions. 23 24 25 26 Keyword: Eye movements, frontotemporal dementia, search, visual scan-paths 27 INTRODUCTION 28 In everyday life, we are constantly presented with 29 search tasks: finding your keys, a familiar person 30 in a crowd, or locating an item on a supermarket 31 shelf. Common visual search tasks often include a 32 significant number of distractors, and the behavior 33 displayed in visual search can be examined in a 34 ∗ Correspondence to: Amanda Douglass, Optometry, School of Medicine, Faculty of Health, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC 3216 Australia. Tel.: +61 3 522 78565; E-mail: Amanda.douglass@deakin.edu.au. laboratory or clinical setting, including dissecting 35 the search task into different components. Differ- 36 ent search behaviors can be elicited by different 37 instructions or by changing the target or number of 38 distractors. Broadly, search tasks can be broken into 39 feature and conjunction tasks. Feature search tasks 40 are those in which the target is clearly identified by 41 one aspect (e.g., color or orientation), while conjunc- 42 tion search tasks are those in which more than one 43 feature must be combined to identify the target (e.g., 44 color and orientation together). Using different search 45 paradigms, different areas of cognitive processing 46 ISSN 1387-2877/19/$35.00 © 2019 – IOS Press and the authors. All rights reserved