Daniel Cipriani | PubMed Health

PubMed2005

Comparing Rasch analyses probability estimates to sensitivity, specificity and likelihood ratios when examining the utility of medical diagnostic tests.

INTRODUCTION: Medical diagnostic tests are evaluated based on measures of sensitivity (Sn), specificity (Sp), and likelihood ratios (LR). These procedures are limited in the event of a biased gold standard or missing data. Interpretations of these measures are frequently inappropriate. PURPOSE: The Rasch measurement model (RMM) was examined as a method to provide evidence of diagnostic test utility in order to overcome the limitations of Sn, Sp, and LR. METHODS: Patients suspected of a knee ligament tear (n = 825) were studied, by evaluating four diagnostic tests. The RMM probability estimates for each test were compared to estimates of Sn, Sp, and LR. RESULTS: The RMM provided probability estimates for the diagnosis that were comparable to likelihood ratios. These probability estimates correlated with the estimates of Sn, Sp, and LR. The RMM estimates were not affected by missing data. DISCUSSION: The RMM may provide an alternative means to study the utility of medical diagnostic tests to estimate the probability of disease presence/absence.

Anterior Cruciate Ligament Injuries↗

PubMed2003

A comparison of two stretching protocols on hip range of motion: implications for total daily stretch duration.

It is theorized that the total stretch time in a day is more important than the actual single stretch duration time. The purpose of this study was to compare 2 stretching protocols, keeping total stretching time equivalent. The 2 protocols were a 10-second duration stretch and a 30-second duration stretch. Although the stretch durations differed, the total stretching time over the course of a day was held constant at 2 minutes for both protocols. Participants were randomly assigned a protocol to each of their legs: subjects stretched 1 leg with the 10-second protocol and the opposite leg with the 30-second protocol. The 10-second stretch was repeated 6 times for a total of 1 minute; the 30-second protocol was repeated 2 times for a total of 1 minute. Stretching was performed twice daily (a total of 2 minutes each day) for 6 weeks. All stretching was performed to the hamstring muscles. Hip flexion measurements were recorded at pretest, 3-weeks, and 6-weeks. Subjects demonstrated significant gains in range of motion for hip flexion over the course of 6 weeks, p = 0.000. No differences existed between the 2 protocols. Range of motion gains were equal between the 2 stretching protocols. The common denominator was total stretch time for a day. Regardless of the duration of a single stretch, the key to improvement was the total daily stretch time. These findings are important as they allow clinicians and individuals to customize stretching protocols to meet individual needs.

Adult↗