Higher visual reliance during single-leg balance bilaterally occurring following acute lateral ankle sprain: A potential central mechanism of bilateral sensorimotor deficits.

BACKGROUND

Single-leg balance (SLB) impairment from eyes-open to eyes-closed trials is significantly greater in patients with chronic ankle instability than in uninjured controls, indicating higher reliance on visual information. It is of clinical interest to see if the visual adaptation occurs immediately after injury.

RESEARCH QUESTION

We aimed to investigate visual reliance in patients with acute lateral ankle sprain (ALAS) during SLB with both injured and uninjured limbs and during double-leg balance (DLB).

METHODS

The study assessed visual reliance of 53 participants: 27 ALAS patients and 26 persons without a history of ALAS. All participants executed DLB with eyes open and closed, and then completed SLB with both the injured and uninjured limbs (side-matched limbs of the uninjured control group) in both visual conditions. Order of limb and visual condition for SLB was randomly selected. Visual reliance was quantified for each postural task with a percent change between the two visual conditions, with the greater change representing higher visual reliance. We performed separate group-by-limb analysis-of-variance with repeated measures for SLB percent scores and independent t-tests for DLB outcomes.

RESULTS

For all SLB measures there were no significant group-by-limb interactions (p > 0.05) but significant group main effects (p = 0.013-0.029). With no side-to-side differences, the ALAS group presented higher declines in SLB from the eyes-open to eyes-closed conditions than did the uninjured control group, indicating higher visual reliance. Similarly, for DLB there were significant group differences for almost all measures (p = <.001-0.037), with the ALAS group showing greater visual reliance.

SIGNIFICANCE

Moderately higher visual reliance occurs acutely and bilaterally during SLB in ALAS patients. Similar visual adaptions also occur during DLS. These findings will provide insight into a central mechanism underlying bilateral sensorimotor deficits following ALAS and allow clinicians to improve current rehabilitation strategies for acute patients.