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.