Study design: Three factors mixed-design with 1 between-subject and 2 within-subject factors.
Objective: To compare the main effects and interactions of postural and cognitive difficulty on quiet stance between subjects with and without nonspecific low back pain (LBP).
Summary of background data: The interference between postural control and cognitive tasks depends on factors such as sensorimotor/cognitive integrity. Changes in peripheral sensory and muscular systems as well as cognitive processes have been observed in LBP patients. It was hypothesized that the effect of cognitive task on postural performance might be different in subjects with nonspecific LBP as compared with healthy individuals. To the authors' knowledge this has not been investigated before.
Methods: Postural stability was measured by center of pressure parameters while nonspecific LBP (n = 22) and healthy (n = 22) subjects randomly performed quiet standing task with 3 levels of difficulty (rigid-surface eyes open, rigid-surface eyes-closed, and foam-surface eyes-closed) in isolation or concurrently with an easy or difficult digits backward cognitive task.
Results: Subjects with nonspecific LBP had less postural sway than healthy subjects, while postural sway decreased with increase in the level of cognitive difficulty. Nonspecific LBP and healthy subjects had larger postural sway at more difficult sensory conditions such as rigid-surface eyes-closed and foam-surface eyes-closed. The response to dual-tasking was not significantly different between the 2 groups.
Conclusion: The dual-tasking did not change the postural performance of nonspecific LBP subjects with low level of pain and disability differently compared to healthy subjects.