Clinical Usefulness of Retropulsion Tests in Persons with Mild to Moderate Parkinson's Disease

People with Parkinson's disease (PwPD) have an increased risk for falls and near falls. They have particular difficulties with maintaining balance against an external perturbation, and several retropulsion tests exist. The Unified PD Rating Scale item 30 (UPDRS30) is the most common, involving an expected shoulder pull. Others recommend using an unexpected shoulder pull, e.g., the Nutt Retropulsion Test (NRT). We aimed to evaluate the clinical usefulness of these tests for detecting future fallers. By using two different golden standards related to self-reported prospective falls and near falls over 6 months following two different time points with 3.5 years between, we estimated sensitivity/specificity, Youden index, predictive values, and likelihood ratios for each test. The different time points yielded a different prevalence of falls and near falls, as well as different predictive values. When comparing the performance of the NRT and UPDRS30 for detecting future fallers, we found that the NRT consistently performed better than UPDRS30. However, neither test exhibited optimal performance in terms of predictive values and associated likelihood ratios. Our findings speak against using either of these tests as a single assessment for this purpose and support previous recommendations of using a multifactorial approach when targeting balance problems in PwPD.