Predicting falls in individuals with Parkinson disease: a reconsideration of clinical balance measures.

BACKGROUND AND PURPOSE: Postural control problems, falls, and fall-related injuries are a common source of morbidity in elderly individuals, especially those with Parkinson disease (PD). Clinical balance tests such as the Berg balance scale and the functional reach have been reported to be useful in assessing fall risk in elderly individuals. However, the utility of commonly used clinical balance tests as accurate screens for fall risk has not been sufficiently examined in persons with PD. The purposes of this study were to identify which commonly used clinical balance tests of persons with PD were predictive of falls, to re-examine the cutoff scores for these tests with the goal of maximizing sensitivity as well as minimizing the negative likelihood ratio, and to determine which of the clinical balance tests had the most value in predicting falls.

PARTICIPANTS: Forty-five persons with a diagnosis of idiopathic PD, aged 39-90 years (mean [sd] =69.94 [11.28]; mean [sd] Hoehn and Yahr level = 2.60 [.66]) participated.

METHODS: Upon initial contact with participants, demographics and fall history were gathered and baseline physical examinations were performed. Each individual underwent balance testing with the functional reach test, the Berg balance scale, the dynamic gait index, timed up and go, and the cognitive timed up and go. Fallers and nonfallers were divided based on fall history and groups were compared on balance test performance. Sensitivity, specificity, likelihood ratios, and receiver operator characteristic curves were calculated for all balance tests.

RESULTS: Twenty-five (55%) participants had a history of falls. Using cut-off scores reported in previous studies, the sensitivity of all tests was low (less than 0.60) and the specificity was high (greater than 0.85). Reconsideration of the cut-off scores resulted in increased sensitivity for all tests (greater than 0.75) and low negative likelihood ratios (less then .30).

DISCUSSION AND CONCLUSION: Given the large financial, psychological, and physical complications that are associated with a fall and relatively little harmful effects of fall prevention interventions, we propose consideration of cut-off scores that maximize sensitivity for individuals with PD. Regardless of the performance on any individual clinical balance test, the multifactorial nature of postural instability in PD may necessitate a battery of tests to provide the most accurate identification of fall risk.