Powered attendant-propelled wheelchair with assist-as-needed control based on individual physical capabilities

This paper discussed if a powered attendant propelled wheelchairs (PAPW) with assist-as-needed control reduces energy consumption and maximise attendant's physical activity in powered system use. This study introduced a PAPW with force velocity assist control (FVAC) based on individual capability of pushing force velocity relationship. This PAPW assists attendant pushing when more pushing force is needed over usual range of individual physical capabilities of pushing. With the PAPW, we investigated the performance of the FVAC and compared it with proportional assist control (PAC) on a flat level surface and a longitudinal slope (6.5%) with three participants. The experimental results showed that the PAPW with the FVAC reduced 50% of pushing force on the slope and this was similar performance of the PAC in terms of assisting. The FVAC also reduced 79% of mean mechanical assisting power on the flat against the PAC. These results support that the PAPW with the FVAC has flexibilities to adapt to individual physical capabilities and provides certain level of physical activities with sufficient assisting when needed, and low energy consumption for long time and distance operations for attendants

Assessment of Tripping Hazards by a Single Step Evaluated by Principal Component Analysis of Pedestrian Feet Movements and Eye Behaviours

The aims in this study was to investigate feet movements and eye behaviours of young and older people when stepping over a small single step up to 25 mm height while walking. In addition, this study investigated what factors in feet movements and eye behaviours can be used to show effectiveness of the preventive measures of tripping. Healthy 12 young and 5 older participants joined this study. A walkway (9.6 m length × 1.2 m width) with a single step chosen from 0, 10, and 25 mm in one of three positions 4.8, 6, and 7.2 m from the start line, was used for measurement of feet movements and eye behaviours in stepping over. Principal component analysis demonstrated to evaluate pedestrian capability of stepping over the single step and showed differences between young and older groups. First principal component might show different walking style, second principal component might show foot strategy of stepping over the single step, and third principal component might show that awareness of the single step. The awareness level of 25 mm step by older group was similar level of the awareness of 10 mm by young group, and older group was struggle to aware 10 mm step, compared with 0 mm case. These findings might be useful to consider how to improve outdoor and indoor environments as well as to assess how physical training, preventive measures, and assistive technologies to reduce the risk of tripping in stepping over the single step

Effects of lighting variability on locomotion in posterior cortical atrophy

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