Estimating the accuracy of muscle response testing: two randomised-order blinded studies.

BACKGROUND: Manual muscle testing (MMT) is a non-invasive assessment tool used by a variety of health care providers to evaluate neuromusculoskeletal integrity, and muscular strength in particular. In one form of MMT called muscle response testing (MRT), muscles are said to be tested, not to evaluate muscular strength, but neural control. One established, but insufficiently validated, application of MRT is to assess a patient's response to semantic stimuli (e.g. spoken lies) during a therapy session. Our primary aim was to estimate the accuracy of MRT to distinguish false from true spoken statements, in randomised and blinded experiments. A secondary aim was to compare MRT accuracy to the accuracy when practitioners used only their intuition to differentiate false from true spoken statements. METHODS: Two prospective studies of diagnostic test accuracy using MRT to detect lies are presented. A true positive MRT test was one that resulted in a subjective weakening of the muscle following a lie, and a true negative was one that did not result in a subjective weakening of the muscle following a truth. Experiment 2 replicated Experiment 1 using a simplified methodology. In Experiment 1, 48 practitioners were paired with 48 MRT-naïve test patients, forming unique practitioner-test patient pairs. Practitioners were enrolled with any amount of MRT experience. In Experiment 2, 20 unique pairs were enrolled, with test patients being a mix of MRT-naïve and not-MRT-naïve. The primary index test was MRT. A secondary index test was also enacted in which the practitioners made intuitive guesses ("intuition"), without using MRT. The actual verity of the spoken statement was compared to the outcome of both index tests (MRT and Intuition) and their mean overall fractions correct were calculated and reported as mean accuracies. RESULTS: In Experiment 1, MRT accuracy, 0.659 (95% CI 0.623 - 0.695), was found to be significantly different (p < 0.01) from intuition accuracy, 0.474 (95% CI 0.449 - 0.500), and also from the likelihood of chance (0.500; p < 0.01). Experiment 2 replicated the findings of Experiment 1. Testing for various factors that may have influenced MRT accuracy failed to detect any correlations. CONCLUSIONS: MRT has repeatedly demonstrated significant accuracy for distinguishing lies from truths, compared to both intuition and chance. The primary limitation of this study is its lack of generalisability to other applications of MRT and to MMT. STUDY REGISTRATION: The Australian New Zealand Clinical Trials Registry (ANZCTR; www.anzctr.org.au ; ID # ACTRN12609000455268 , and US-based ClinicalTrials.gov (ID # NCT01066312 ).

The Impact of Using Emotionally Arousing Stimuli on Muscle Response Testing Accuracy.

INTRODUCTION: Muscle response testing (MRT) is an assessment method used by 1 million practitioners worldwide, yet its usefulness remains uncertain. The aim of this study, one in a series assessing the accuracy of MRT, was to determine whether emotionally arousing stimuli influence its accuracy compared to neutral stimuli. METHODS: To assess diagnostic test accuracy 20 MRT practitioners were paired with 20 test patients (TPs). Forty MRTs were performed as TPs made true and false statements about emotionally arousing and neutral pictures. Blocks of MRT alternated with blocks of intuitive guessing (IG). RESULTS: MRT accuracy using emotionally arousing stimuli was different than when using neutral stimuli. However, MRT accuracy was found to be significantly better than IG and chance. Similar to previous studies in this series, this study failed to detect any characteristic that consistently influenced MRT accuracy. CONCLUSION: Using emotionally arousing stimuli had no effect on MRT accuracy compared to using neutral stimuli. This study would have been strengthened by adding personally relevant lies instead of impersonal stimuli. A limitation of this study is its lack of generalizability to other applications of MRT. This study shows that a simple yet robust methodology for assessing MRT as a diagnostic tool can be implemented effectively.

Does evidence-based practice improve patient outcomes? An analysis of a natural experiment in a Spanish hospital.

RATIONALE, AIMS AND OBJECTIVES: Evidence-based practice (EBP) is widely promoted, but does EBP produce better patient outcomes? We report a natural experiment when part of the internal medicine service in a hospital was reorganized in 2003 to form an EBP unit, the rest of the service remaining unchanged. The units attended similar patients until 2012 permitting comparisons of outcomes and activity. METHODS: We used routinely collected statistics (2004-11) to compare the two different methods of practice and test whether patients being seen by the EBP unit differed from standard practice (SP) patients. Data were available by doctor and year. To check for differences between the EBP and SP doctors prior to reorganization, we used statistics from 2000 to 2003. We looked for changes in patient outcomes or activity following reorganization and whether the EBP unit was achieving significantly different results from SP. Data across the periods were combined and tested using Mann-Whitney test. RESULTS: No statistically significant differences in outcomes were detected between the EBP and the SP doctors prior to reorganization. Following the unit's establishment, the mortality of patients being treated by EBP doctors compared with their previous performance dropped from 7.4% to 6.3% (P < 0.02) and length of stay from 9.15 to 6.01 days (P = 0.002). No statistically significant improvements were seen in SP physicians' performance. No differences in the proportion of patients admitted or their complexity between the services were detected. Despite this, EBP patients had a clinically significantly lower risk of death 6.27% versus 7.75% (P < 0.001) and a shorter length of stay 6.01 versus 8.46 days (P < 0.001) than SP patients. Readmission rates were similar: 14.4% (EBP); 14.5% (SP). EBP doctors attended twice as many patients/doctor as SP doctors. CONCLUSION: The EBP unit was associated with better patient outcomes and more efficient performance than achieved by the same physicians previously or by SP concurrently.