Does the Hawthorne effect influence gait assessment in stroke patients?

Abstract

Background

Gait assessments are essential in post-stroke rehabilitation to quantify impairments, identify underlying causes, and guide treatment. Gait assessments may, however, be influenced by the “Hawthorne effect”, the phenomenon of behavioral change in response to observation. This has not been studied properly in people post-stroke. This study examined the Hawthorne effect during post-stroke gait assessment, distinguishing between observation only and observation plus awareness of gait measurement.

Methods

Twenty adults post-stroke walked during three gait conditions: unobserved walking, walking while being observed, and walking with observation plus awareness of gait measurement. Spatiotemporal gait parameters were collected using inertial measurement units. Primary outcome was gait speed. Secondary outcomes were stride length, stride time, stride time variance and stance time symmetry.

Results

A repeated measures ANOVA revealed significant differences in gait speed, stride length, and stride time. Post-hoc tests showed that observation plus awareness of measurement led to higher gait speed (p = 0.004, diff=0.05 m/s) and stride length (p = 0.010, diff=0.03 m), and shorter stride time (p = 0.020, diff=-0.03 s) compared to unobserved walking. Gait speed was also higher (p = 0.004, diff=0.03 m/s) and stride time was also shorter (p = 0.040, diff=-0.02 s) in the observed plus measured condition compared to the observed condition. No significant differences were found between the observed and unobserved condition, or for stride time variance and stance time symmetry.

Conclusion

While observation plus awareness of gait measurement significantly influenced gait parameters post-stroke, changes were small and did not exceed the minimal clinical important differences. Thus, the Hawthorne effect is unlikely to influence clinical decision-making during post-stroke gait assessment.