| Context: An individual's risk of injury and his/her ability to balance is linked in a cyclical relationship that outlines the necessity of balance assessment tools in the diagnosis, prevention and rehabilitation of injuries. Despite this necessity, many challenges present in relation to assessment protocols and utility. For concussion assessment, the Balance Error Scoring System and Sensory Organization Test provide tools that are sensitive and cost effective but neither measure is both. The unique nature of the Star Excursion Balance Test (SEBT) may provide both a cost effective and sensitive measure of balance for concussion assessment though the current protocol may not even be sufficient. The Condition-Modified Star Excursion Balance Test (CM-SEBT) uses the original SEBT protocol under conditions of altered sensory inputs to challenge the balance mechanism. Objective: To examine reliability and validity of the CM-SEBT in comparison to other commonly used balance measures. Design: Repeated measures design. Setting: Research laboratory. Participants: Forty-seven healthy, young adults (20 males: 21.15+/-2.48 yrs, 82.72+/-14.62 kg, 179.36+/-7.55 cm; 27 females: 22.70+/-4.21 yrs, 66.56+/-14.47 kg, 162.51+/-7.08 cm) voluntarily participated in this study. All participants reported no pathologies or medicinal intake that altered balance while enrolled in the study. Interventions: Each participant underwent testing on three different measures of balance during two test sessions. Test sessions were separated by 57.72+/-24.19 (median=50) days. Each participant performed on the Balance Error Scoring System, Sensory Organization Test, and the CM-SEBT. The altered conditions of the CM-SEBT included: stable surface-eyes open (SO), stable surface-eyes closed (SC), unstable surface-eyes open (UO), and unstable surface-eyes closed (UC). Main Outcome Measures: Intra-class correlation coefficients [ICC(2,1)&ICC(2,k)] were calculated using singular and average measures for reach direction by condition to evaluate test-retest reliability. These values were used in the determination of clinically applicable guidelines in the detection of pathological conditions. Additionally, CM-SEBT reach distance was compared to posturography measures, the Sensory Organization Test, and the Balance Error Scoring System. Results: The reliability of the CM-SEBT was best when using an average of three measured trials, ranging between 0.73-0.92 depending on gender, condition and reach direction. At the 95% confidence interval, clinical cut-off scores for normalized average scores were determined for each direction and condition since these scores indicated the highest reliability. Combined gender cut-off scores by direction and condition are as follows: anterior reach direction - SO=0.08, SC=0.10, UO=0.16, UC=0.08; medial reach direction: SO=0.11, SC=0.17, UO=0.08, UC=0.13; and posterior reach direction: SO=0.18, SC=0.11, UO=0.23, UC=0.20. Male and female differences were minimal but increases in the posterior direction, especially on an unstable surface. No consistent relationships were elucidated between the CM-SEBT reach distance and outcomes related to the other measures of balance. Conclusions: Reliability of the CM-SEBT, spanning test separation of approximately eight weeks, is well within clinical standards. Eliminating visual input while performing on an unstable surface produced the lowest reliability in all directions; yet, these values were still above previous reports of commonly used balance measures; rendering the CM-SEBT as a potential tool in clinical decision making regarding balance performance. The CM-SEBT, as a measure of balance, is a unique assessment of balance that is not correlated to outcomes of the SOT and/or BESS. Despite these findings, the clinical utility of the CM-SEBT is in need of continued investigation; including examinations of performance in pathological populations to further develop interpretive guidelines. |
