Visual Scanning and Attentional Biases in Alzheimer's Disease: Assessing Symptoms and Outcomes

Current assessments of cognition and behaviour in Alzheimer’s disease (AD) rely on indirect evaluations and are complicated by communication deficits, hampering ability to effectively prescribe and monitor pharmacotherapy. The purpose of this thesis was to determine whether direct measurements of visual scanning behaviour can optimize symptom and outcome assessments in this patient population. In the four studies conducted, a non-verbal eye tracking technique was used to characterize visual scanning behaviour in order to quantify methods of measuring cognition, behaviour and pharmacotherapy-induced changes in AD patients. To evaluate selective attention towards novel stimuli or novelty preference in AD, mild-to-moderate AD patients (n=41) and elderly controls (n=24) viewed novel and repeated images simultaneously. Compared with controls, AD patients spent less time on novel than repeated images (F(1,63)=11.18, p=0.001). Reduced novelty preference was associated with worse cognition (Standardized Mini-Mental State Examination, sMMSE, r(63)=0.29, pPh.D