An alternative clinical postural stability test for patients with Parkinson's disease.

We compared the sensitivity and consistency of a new Push and Release Test versus the Pull Test (item 30 of the Unified Parkinson's Disease Rating Scale; UPDRS) as clinical measures of postural stability. Subjects with Parkinson's disease and age-matched control subjects participated in 3 protocols investigating: (1) the sensitivity and specificity of the two tests related to the subjects' balance confidence, as measured by the Activities-specific Balance Confidence (ABC) scale, (2) the inter-rater reliability of the two tests, and (3) the consistency of the perturbation forces applied to the subjects by each balance test. As a test for concurrent validity, the balance tests were also compared with the subjects' retrospective reports of fall frequency. Compared with the Pull Test, the Push and Release Test was more sensitive to subjects with low balance confidence, but less specific for subjects with high balance confidence. The inter-rater correlations were higher with the Push and Release Test. Examiners applied more consistent perturbation forces to the subjects with the Push and Release Test than with the Pull Test. The Push and Release Test correlated better with self-reported falls. Therefore, the Push and Release Test provided a more sensitive and consistent test of postural stability than the Pull Test.