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Contribution of Age and Balance Confidence to Functional Mobility Test Performance: Diagnostic Accuracy of L Test and Normal-Paced Timed Up and Go

Medley, Ann PT, PhD, CEEAA; Thompson, Mary PT, PhD, GCS

Journal of Geriatric Physical Therapy: January/March 2015 - Volume 38 - Issue 1 - p 8–16
doi: 10.1519/JPT.0000000000000015
Research Reports

Background and Purpose: Falls are a public health priority. Contribution of age and balance confidence to functional mobility is unknown. Appropriate cutoff scores for normal-paced Timed Up and Go (TUG) and L test may improve ability to determine fall risk. Purposes were to determine the contribution of age and balance confidence to functional mobility, determine the association between balance confidence and fall risk, and propose cutoffs.

Methods: A prospective, descriptive study was conducted in the community with 105 apparently healthy adults at the age of 60 to 96 years. Participants provided fall history. Examiners administered the Activities-Specific Balance Confidence Scale, Dynamic Gait Index (DGI), Functional Gait Assessment, TUG, and L test. Linear regression determined the balance confidence contribution. Multivariate analysis of covariance determined differences between participants with high and low confidence. Sensitivity, specificity, overall diagnostic accuracy, and receiver operating characteristics curves were used to estimate cutoffs.

Results: Performance across functional mobility tests declined with age. A total of 46 participants had low balance confidence. Depending on the outcome measure, 16% to 30% of participants' balance confidence and physical performance did not match. Regression analysis revealed that the best model combines age and balance confidence. Regardless of age, participants with high and low balance confidence differed on the basis of multivariate analysis of covariance. Receiver operating characteristics curves supported the diagnostic accuracy of 12 or more seconds (normal-paced TUG) and 25.5 or more seconds (L test) cutoffs.

Discussion: We confirmed that functional mobility, as measured by the L test, declines with age similar to other outcome measures. Balance confidence contributes to functional mobility performance, and the 2 constructs do not match about 25% of the time. Because these constructs may not match, the need to formally assess balance confidence is warranted when concerned about fall risk. Cutoff scores to predict fall risk for the L test and normal-paced TUG are proposed using the DGI cutoff (≤19) as the reference standard. The proposed cutoff scores merit further testing with prospective fall data as the reference standard.

Conclusions: Older adults would benefit if clinicians would assess balance confidence.

School of Physical Therapy, Texas Woman's University, Dallas.

Address correspondence to: Ann Medley, PT, PhD, CEEAA, School of Physical Therapy, Texas Woman's University, 5500 Southwestern Medical Ave, Dallas, TX 75235 (smedley@twu.edu).

Preliminary data for this study were presented as a poster at the American Physical Therapy Association Annual Conference, San Antonio, Texas, in 2008 and at the American Physical Therapy Association, Combined Sections Meeting, New Orleans, Louisiana, in 2011.

Conflict of interest and source of funding: None declared.

Bernadette Williams-York was the Decision Editor.

© 2015 Academy of Geriatric Physical Therapy, APTA