Divided Attention Alters Trailing Limb Stepping activity– A Dual-task Study

Research Objectives: To investigate the changes of lower extremity joint kinematics and gait characteristics of the trailing leg during the dual-task obstacle crossing task (OCT).

Design: Observational study from a healthy cohort

Setting: Hospital and research institute setting

Participants: Nine young healthy participants (4 females and 5 males; age:27.8±4.1 years old) were recruited from University of Kansas Medical Center following the volunteer sample selection procedure. Key eligibility criteria included: (1) be able to independently walk for 30 minutes; (2) no neurological disorders that cause postural instability; (3) no recent ( < 6 months) lower extremity fracture.

Interventions: Participants were instructed to walk on the instrumented C-Mill VR treadmill (Motek, the Netherlands) and step over obstacle images projected on the treadmill belt using right legs as leading legs. During the dual-task OCT, an auditory Stroop test was administered concurrently. Eight-sensor APDM Moveo Explorer system (Portland, OR) was used to collect the trailing leg’s joint kinematics and spatiotemporal gait characteristics.

Main Outcome Measures: The trailing leg’s joint angles and spatiotemporal characteristics while stepping over the obstacle in a single- and dual- task condition were measured. We hypothesized that both joint angles and characteristics would be significantly altered in the dual-task setting.

Results: The maximal knee extension was significantly decreased. The double-support time was significantly extended while the stride length was significantly decreased. There has a trending that the height of foot elevation at mid-swing phase of stepping was decreased (ρ = 0.07).

Conclusions: Our hypothesis was supported through the decreased knee extension, stride length and increased double-support time. Future studies are warranted to identify trailing leg’s stepping strategies among aging or neurodegenerative populations.

Author(s) Disclosures: No conflict of interests was disclosed in this study.