THE IMPACT OF EXTRINSIC VISUAL FEEDBACK AND ADDITIONAL COGNITIVE OR PHYSICAL DEMANDS ON SINGLE-LIMB POSTURAL CONTROL IN INDIVIDUALS WITH ANKLE INSTABILITY Jacob Miller, SPT 1 ; You-jou Hung, PT, MS, PhD, CSCS 1 1 Department of Physical Therapy, Angelo State University, San Angelo, TX The purpose of this study was to compare the default setting the Athletic Single Leg Stability Test of the Biodex Balance System to some modified protocols that better resemble real-life scenarios, and to investigate the results’ correlation to the severity of ankle instability, quantified by the Cumberland Ankle Instability Tool (CAIT). Ankle instability is a very common problem for individuals with a history of ankle sprains. About 73% of the individuals who once sprained their ankles are likely to experience recurrent injuries. Single-limb postural control testing using the Biodex Balance System has been considered an objective measurement of ankle stability. However, the machine provides direct extrinsic visual feedback to the subject from a monitor and compromises its functional significance. Seventeen individuals (4 males, 13 females) aged participated in the study. The inclusion criteria includes: 1) have one or more ankle sprains over the injured ankle, 2) have the latest ankle sprain occurred within the past year, 3) have no pain or discomfort over the injured ankle at participation, 4) have no other prior injury that received medical attention for the injured ankle. The CAIT score ranges from 10 to 28 for the participants. The default setting of the Athletic Single Leg Stability Test consists of 3 trials with 20 seconds per trial at platform level 4. The 4 testing protocols are shown in the middle panel. For the protocol with added cognitive demands, subjects were asked to continue subtracting 7 from at set of predetermined numbers (eg, 110). For the protocol with added physical demands, subjects were asked to catch and throw a basketball with an examiner located 6 feet away once every second (guided by a metronome), while maintaining the balance with the support leg. PURPOSE ANALYSES CONCLUSIONS SUBJECTS One-way ANOVA with repeated measures was used to compare the 4 different testing protocols. Pearson Correlation was used to examine the correlations between the Biodex and the CAIT scores. Significance level (p-values) was set at 0.05 for all comparisons. The subject’s single-limb postural control varied significantly among different protocols (F=103; p<.01). Pairwise comparison shows subjects performed significantly worse in all modified protocols (p<.01 in all comparisons) compared to the default protocol, but there is no significant difference between “no extrinsic visual feedback” and “no extrinsic visual feedback with cognitive demands” protocols. Scores from all 3 modified protocols are significantly correlated with the default protocol. However, scores from none of the 4 protocols are significantly correlated with the CAIT scores. Although The Athletic Single Leg Stability Test is an established objective test, subjects performed much worse in other modified testing protocols that better resemble real-life scenarios and merit a larger functional significance. Without extrinsic visual feedback, adding a cognitive demand did not further compromise ankle stability. However, adding a physical demand that simulate sport activities (eg, basketball) can greatly compromise ankle stability. The validity of the default and modified single-limb testing should be further examined with a larger sample size. dback from a monitor and/or with added physical Using the Athletic Single Leg Stability Test, results show single-limb postural control is much worse without extrinsic visual feedback from a monitor and/or with added physical demands. Clinicians and researchers should consider the specificity of a patient’s sport/activity and incorporate proper physical demands in ankle stability testing and rehabilitation. BACKGROUNDS RESULTS CLINICAL RELEVANCE METHODS 1.Default with extrinsic visual feedback from the monitor 2. No extrinsic visual feedback from the monitor 3. No extrinsic visual feedback with cognitive demands 4. No extrinsic visual feedback with physical demands