Measuring balance confidence after spinal cord injury: the reliability and validity of the Activities-specific Balance Confidence Scale

Abstract

Context/Objective: The study objectives were to evaluate the test-retest reliability, convergent validity, and discriminative validity of the Activities-specific Balance Confidence (ABC) scale in individuals with incomplete spinal cord injury (iSCI).

Design: Prospective, cross-sectional study.

Setting: Laboratory.

Participants: Twenty-six community-dwelling individuals with chronic iSCI (20 males, 59.7 + 18.9 years old) and 26 age- and sex-matched able-bodied (AB) individuals participated.

Interventions: None.

Outcome Measures: Measures of balance and gait were collected over two days. Clinical measures included the ABC scale, Mini-Balance Evaluation System’s Test, 10-meter Walk Test, SCI Functional Ambulation Profile, manual muscle testing of lower extremity muscles, and measures of lower extremity proprioception and cutaneous pressure sensitivity. Biomechanical measures included the velocity and sway area of centre of pressure (COP) movement during quiet standing.

Results: The ABC scale demonstrated high test-retest reliability (intraclass correlation coefficient = 0.93) among participants with iSCI. The minimal detectable change was 14.87%. ABC scale scores correlated with performance on all clinical measures (ρ=0.60-0.80, P<0.01), with the exception of proprioception and cutaneous pressure sensitivity (P=0.20–0.70), demonstrating convergent validity. ABC scale scores also correlated with overall COP velocity (ρ=-0.69, P<0.001) and COP velocity in the anterior-posterior direction (ρ=-0.71, P<0.001). Participants with iSCI scored significantly lower on the ABC scale than the AB participants (P<0.001), and the area under the receiver operating characteristic curve was 0.95, demonstrating discriminative validity.

Conclusion: The ABC scale is a reliable and valid measure of balance confidence in community-dwelling, ambulatory individuals with chronic iSCI.

Keywords:

• Spinal cord injuries, Balance confidence, Validity, Reliability

Acknowledgements

Funding for this research was provided by the Saskatchewan Health Research Foundation (grant to KEM and ARO) and the Ontario Neurotrauma Foundation (grant to KEM).

Disclaimer statements

Contributors None.

Funding Saskatchewan Health Research Foundation and Ontario Neurotrauma Foundation.

Declaration of interest None.

Conflicts of interest None.

Ethics approval University of Saskatchewan Research Ethics Board.