Nodoka Kimura1, Robert van Deursen2. 1. Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), 1-4 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address: kimura.nodoka.86n@kyoto-u.jp. 2. School of Healthcare Sciences, Cardiff University, Heath Park Campus, Cardiff CF14 4XN, Wales, UK. Electronic address: vandeursenr@cardiff.ac.uk.
Abstract
BACKGROUND: Visual dual-task skills are essential for stable ambulation in everyday life such as walking while reading text. Gait analysis in a virtual environment can provide insight into altered walking performance while visual dual-tasking. RESEARCH QUESTION: How visual dual-tasking including cognitive load of reading text and altered optical flow influences walking speed and stability in healthy adults? Also, is there a relationship between the mediolateral centre of mass(CoM) displacement and mediolateral trunk movement? METHODS: Nineteen able-bodied young adults performed self-selected walking on a treadmill in a virtual environment under the following three conditions; single-task walking, walking while viewing scrolling lines, and walking while reading text scrolling on the screen. Three-dimensional motion analysis was used to measure the effect of dual-tasking on gait velocity, step length, mediolateral CoM displacement, and mediolateral thorax inclination. RESULTS: The effect of visual dual-tasking showed significantly increased walking speed and longer step length compared to single-tasking. The cognitive load of reading text while walking had a significant impact on reduced step length variability and greater mediolateral CoM displacement. This was related to the mediolateral thorax inclination. SIGNIFICANCE: A visual dual-task influences gait through altered optical flow and a cognitive load effect. Altered optical flow increased walking speed whilst the visual attention to read text affected foot placement and upright trunk posture, together with greater mediolateral CoM displacement. Thus, dual-tasking of reading text in a virtual environment substantially affected walking stability in healthy young people. This paradigm is therefore useful for assessment of walking stability in daily life and in the clinical setting.
BACKGROUND: Visual dual-task skills are essential for stable ambulation in everyday life such as walking while reading text. Gait analysis in a virtual environment can provide insight into altered walking performance while visual dual-tasking. RESEARCH QUESTION: How visual dual-tasking including cognitive load of reading text and altered optical flow influences walking speed and stability in healthy adults? Also, is there a relationship between the mediolateral centre of mass(CoM) displacement and mediolateral trunk movement? METHODS: Nineteen able-bodied young adults performed self-selected walking on a treadmill in a virtual environment under the following three conditions; single-task walking, walking while viewing scrolling lines, and walking while reading text scrolling on the screen. Three-dimensional motion analysis was used to measure the effect of dual-tasking on gait velocity, step length, mediolateral CoM displacement, and mediolateral thorax inclination. RESULTS: The effect of visual dual-tasking showed significantly increased walking speed and longer step length compared to single-tasking. The cognitive load of reading text while walking had a significant impact on reduced step length variability and greater mediolateral CoM displacement. This was related to the mediolateral thorax inclination. SIGNIFICANCE: A visual dual-task influences gait through altered optical flow and a cognitive load effect. Altered optical flow increased walking speed whilst the visual attention to read text affected foot placement and upright trunk posture, together with greater mediolateral CoM displacement. Thus, dual-tasking of reading text in a virtual environment substantially affected walking stability in healthy young people. This paradigm is therefore useful for assessment of walking stability in daily life and in the clinical setting.