title: Increasing cognitive load attenuates right arm swing in healthy human walking.
abstract: Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task-primarily involving left hemisphere structures-would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18-80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry-an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right-increased significantly under dual-task conditions in those aged 40-59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Tim
authors.identifier: 0000-0001-8246-4957
authors.initials: T
authors.lastname: Killeen
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Easthope
authors.affiliation: Department of Neurology , University Hospital Zurich , Frauenklinikstrasse 26, 8091 Zurich , Switzerland.
authors.forename: Linard
authors.initials: L
authors.lastname: Filli
authors.affiliation: Department of Neurology , University Hospital Zurich , Frauenklinikstrasse 26, 8091 Zurich , Switzerland.
authors.forename: Lilla
authors.initials: L
authors.lastname: Lőrincz
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Miriam
authors.initials: M
authors.lastname: Schrafl-Altermatt
authors.affiliation: Department of Neurology , University Hospital Zurich , Frauenklinikstrasse 26, 8091 Zurich , Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Brugger
authors.affiliation: Department of Neurology , Helios-Klinik Hagen-Ambrock , Ambrocker Weg 60, 58091 Hagen , Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Linnebank
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Armin
authors.initials: A
authors.lastname: Curt
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Björn
authors.initials: B
authors.lastname: Zörner
authors.affiliation: Spinal Cord Injury Center , University Hospital Balgrist , Forchstrasse 340, 8008 Zurich , Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Bolliger
keywords: arm swing; central pattern generator; cognitive control; dual-task; gender; motor control