P30: Attentional allocation in dual-task walking: effects of hypermobile Ehlers-Danlos syndrome and cognitive demand

International audience; Hypermobile Ehlers–Danlos syndrome (hEDS) is a connective tissue disorder characterized by proprioceptive impairments. Previously, it has been shown that hEDS patients have altered gait patterns; however,no study has investigated how hEDS patients spontaneously allocate attention during dual-task walking under varying cognitive demand. A low cognitive demand would allow patients to allocate sufficient attention to both tasks; conversely, a high cognitive demand would require them to prioritize gait control over the cognitive task performance.12 hEDS patients and 12 controls walked on a self-paced treadmill for 2 minutes during single-task and dual-task (while performing an auditory 0-back or 2-back task) in a virtual environment. Separates ANOVAs were conducted for cognitive (d-prime, reaction time) and gait (mean and standard deviation of spatio-temporal parameters, statistical persistence/anti-persistence in step speed time series) dependent variables.Patients showed lower cognitive and gait performance compared to controls. Cognitive performance further declined with a concurrent walking task in patients only. However, dual-task-related changes in gait were similar in both groups, revealing beneficial and detrimental effects under low and high cognitive demand, respectively.Gait relies more on cognitive control mechanisms in patients so that, as the demand increases, hEDS patients are more likely to prioritize gait control at the expense of cognitive performance.