title: Response inhibition and avoidance of virtual obstacles during gait in healthy young and older adults.
abstract: Adjustments of preplanned steps are essential for fall avoidance and require response inhibition. Still, inhibition is rarely tested under conditions resembling daily living. We evaluated the ability of young and older adults to modify ongoing walking movements using a novel precision step inhibition (PSI) task combined with an auditory Stroop task. Healthy young (YA, n=12) and older (OA, n=12) adults performed the PSI task at 4 individualized difficulty levels, as a single and dual task (DT). Subjects walked on a treadmill by stepping on virtual stepping stones, unless these changed color during approach, forcing the subjects to avoid them. OA made more failures (40%) on the PSI task than YA (16%), but DT did not affect their performance. In combination with increased rates of omitted Stroop task responses, this indicates a "posture first" strategy. Yet, adding obstacles to the PSI task significantly deteriorated Stroop performance in both groups (the average Stroop composite score decreased by 13% in YA and 27% in OA). Largest deficit of OA was observed in rates of incorrect responses to incongruent Stroop stimuli (OA 35% and YA 12%), which require response inhibition. We concluded that the performance of OA suffered specifically when response inhibition was required.
authors.affiliation: KU Leuven, Department of Kinesiology, Tervuursevest 101 - Box 1501, 3001 Heverlee, Belgium. Electronic address: zrinka.potocanac@faber.kuleuven.be.
authors.forename: Zrinka
authors.initials: Z
authors.lastname: Potocanac
authors.affiliation: Tolbrug Specialized Rehabilitation, Henri Dunantstraat 7, 5223 GZ 's-Hertogenbosch, The Netherlands; Radboud UMC, Department of Rehabilitation, Centre of Evidence Based Practice, Reinier Postlaan 4, 6525 GC Nijmegen, The Netherlands. Electronic address: ellen.smulders@radboudumc.nl.
authors.forename: Ellen
authors.initials: E
authors.lastname: Smulders
authors.affiliation: Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. Electronic address: m.pijnappels@vu.nl.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Pijnappels
authors.affiliation: KU Leuven, Department of Rehabilitation Sciences, Tervuursevest 101 - Box 1501, 3001 Heverlee, Belgium. Electronic address: sabine.verschueren@faber.kuleuven.be.
authors.forename: Sabine
authors.initials: S
authors.lastname: Verschueren
authors.affiliation: KU Leuven, Department of Kinesiology, Tervuursevest 101 - Box 1501, 3001 Heverlee, Belgium; Sint Maartenskliniek Nijmegen, Department of Research, Development and Education, Postbus 9011, 6500 GM Nijmegen, The Netherlands. Electronic address: jacques.duysens@faber.kuleuven.be.
authors.forename: Jacques
authors.initials: J
authors.lastname: Duysens
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000367:Age Factors; D000368:Aged; D000465:Algorithms; D001288:Attention / Q000502:physiology; D003116:Color; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D009048:Motor Skills; D011187:Posture; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time; D015203:Reproducibility of Results; D057190:Stroop Test; D013647:Task Performance and Analysis; D016138:Walking / Q000502:physiology; D055815:Young Adult
keywords: Accidental falls; Dual task; Obstacle avoidance; Older adults; Response inhibition; Stroop task