ObjectiveDeficits in spatial navigation are characteristic and disabling features of typical Alzheimer's disease (tAD) and posterior cortical atrophy (PCA). Visual cues have been proposed to mitigate such deficits; however, there is currently little empirical evidence for their use.MethodsThe effect of visual cues on visually guided navigation was assessed within a simplified real‐world setting in individuals with tAD (n = 10), PCA (n = 8), and healthy controls (n = 12). In a repeated‐measures design comprising 36 trials, participants walked to a visible target destination (an open door within a built environment), with or without the presence of an obstacle. Contrast and motion‐based cues were evaluated; both aimed to facilitate performance by applying perceptual changes to target destinations without carrying explicit information. The primary outcome was completion time; secondary outcomes were measures of fixation position and walking path directness during consecutive task phases, determined using mobile eyetracking and motion capture methods.ResultsResults illustrate marked deficits in patients’ navigational ability, with patient groups taking an estimated two to three times longer to reach target destinations than controls and exhibiting tortuous walking paths. There were no significant differences between tAD and PCA task performance. Overall, patients took less time to reach target destinations under cue conditions (contrast‐cue: 11.8%; 95% CI: [2.5, 20.3]) and were more likely initially to fixate on targets.InterpretationThe study evaluated navigation to destinations within a real‐world environment. There is evidence that introducing perceptual changes to the environment may improve patients’ navigational ability.

New train stock or train services are continually being added to the network in the UK. Their design, in conjunction with European Regulations on train floor and rail height, means there is often a gap between train and platform necessitating at least one physical step. This paper presents the results from a series of experiments testing the time required to board or alight a train across three different gap heights. The experiments were designed to test for the effect of age and luggage type on the time to board or alight. As expected, more steps result in a longer time required to board or alight. More interesting is the effect of age and luggage on time to board and alight with younger people being relatively unaffected by the presence of steps and luggage, whereas both these factors hinder elderly people. The quantification of these effects has implications for accessibility of train services and for train dwell times and can be used by others in the design and planning stages of rail projects.

Introduction Clinical reports describe patients with Alzheimer's disease (AD) exhibiting atypical adaptive walking responses to the visual environment; however, there is limited empirical investigation of such behaviors or factors modulating their expression. We aim to evaluate effects of lighting‐based interventions and clinical presentation (visual‐ vs memory‐led) on walking function in participants with posterior cortical atrophy (PCA) and typical AD (tAD). Methods Participants with PCA (n = 10), tAD (n = 9), and healthy controls (n = 12) walked to visible target destinations under different lighting conditions within two pilot repeated‐measures design investigations (Experiment 1: 32 trials per participant; Experiment 2: 36 trials per participant). Participants walked to destinations with the floorpath interrupted by shadows varying in spatial extent (Experiment 1: no, medium, high shadow) or with different localized parts of the environment illuminated (Experiment 2: target, middle, or distractor illuminated). The primary study outcome for both experimental tasks was completion time; secondary kinematic outcomes were proportions of steps identified as outliers (Experiment 1) and walking path directness (Experiment 2). Results In Experiment 1, PCA participants overall demonstrated modest reductions in time taken to reach destinations when walking to destinations uninterrupted by shadows compared to high shadow conditions (7.1% reduction [95% confidence interval 2.5, 11.5; P = .003]). Experiment 2 found no evidence of differences in task performance for different localized lighting conditions in PCA participants overall. Neither experiment found evidence of differences in task performance between conditions in tAD or control participants overall. Completion time in both patient groups was longer relative to controls, and longer in PCA relative to tAD groups. Discussion Findings represent a quantitative characterization of a clinical phenomenon involving patients misperceiving shadows, implicating dementia‐related cortico‐visual impairments. Results contribute to evidence‐based design guidelines for dementia‐friendly environments.

This study aimed to examine simple locomotion and eye behaviour of individuals with Posterior Cortical Atrophy (PCA) and typical Alzheimer's disease (tAD) within a simulated real-world environment. Posterior cortical atrophy (PCA) is a neurodegenerative condition characterised by parietal, occipital and occipito-temporal tissue loss and progressive impairment of higher-order visual function in contrast to relatively spared memory and language. Targeted types of locomotion were walking in a series of corridors, up or down stairs, and across an open room with or without the presence of an obstacle. Eye tracking measures and inertial moment units (IMU) were used in this experiment, and resultant acceleration of left foot and fixation duration were extracted. Findings from three participants are presented as a case series: one control, one PCA and one tAD patient. The averaged resultant acceleration of PCA patient was the slowest in all types of locomotion, especially in stairs. The averaged resultant accelerations of PCA and tAD participants were slower than the control participant. The PCA participant had longer mean fixation durations than the tAD and control participants, however, mean fixation duration was similar between tAD and control participants. Results may help characterise locomotion and eye behaviour in PCA and tAD and may suggest ways to support effective diagnosis and assessment of disease progression.

The aim of the study was to understand how patients with dementia were able to navigate in a domestic environment, and whether the presence of visual cues could assist in route finding. A simulated domestic environment was created in the Pedestrian Accessibility and Movement Environment Laboratory (PAMELA) comprising three different types of corridors and an open room with three doors. Three groups of subjects were studied: i) posterior cortical atrophy; ii) typical Alzheimer's disease; iii) age-and gender matched controls. Foot-mounted inertial measurement units (IMUs) were used to measure accelerations in 3D. Data from the sensors was transmitted wirelessly to a laptop computer. Local accelerations were converted to global accelerations, and double integration was performed to calculate displacement; corrections for sensor drift were performed during this process.