Effective Spinal Rehab Starts with Accurate Performance Measures
Optimum management of spinal conditions is predicated upon accurate assessment. Without an accurate performance measure, you cannot know whether spinal rehab is needed, whether a recommended intervention is effective, or when to stop. Data from inaccurate measures can lead to poor clinical decisions. Therefore, the first step for practitioners is to select the best performance-based spinal assessment measures.
Qualities of a Good Physical Performance Measure
A good physical performance measure will demonstrate reliability, validity and clinical utility, and it will provide normative data.
Reliability in screening/diagnostic testing is how closely repeated measures on the same subject agree when made by different observers or the same observer at different times. If a test is unreliable, test results will change without the patient’s condition really changing.
Validity is the degree to which a measurement truly measures what it purports to measure. There are two primary methods of testing the validity of physical performance measures: discriminate validity and predictive validity. Ideally, a physical performance measure would demonstrate good validity for both testing models. However, it is acceptable for the measure to demonstrate good validity for just one of the testing models if the other testing model is absent, but has not failed. Moreover, a valid test finds almost all patients who have the condition and hardly any patients who do not have the condition.
Clinical utility is just as important as reliability and validity. Crucial components of clinical utility for a physical performance test include: 1) simple to administer and interpret, 2) requires a minimum amount of equipment, 3) requires a minimum amount of time to administer, 4) requires a minimum amount of space to administer, and 5) requires a minimum amount of cost to administer.
Normative data is important, because it provides a target of how things should be. It supplies a benchmark that allows for comparisons and monitoring progress. The minimum requirements for normative data for a physical performance measure are that the sample frame be from healthy controls and that the research team provide gender specifics (assuming the data is from a quality study).
The Search for Good Physical Performance Measures
The following electronic databases were used to search the literature for relevant studies: MEDLINE, EMBASE, and CINAHL. "Related articles" in relevant MEDLINE (PubMed) papers were accessed, and articles cited in the bibliographies of relevant papers were retrieved. Several popular spinal rehabilitation texts were reviewed (e.g., McGill, Liebenson).
Thirty-six physical performance measures failed to meet the above quality standards. Among the measures that failed were the popular cervical and lumbar muscle strength tests.
Five test met the standards of a test that provides good clinical guidance to the doctor and patient. These tests have sound psychometric qualities: they are reliable, valid (discriminate and/or predictive validity), provide clinical utility (inexpensive, quick and easy to perform) and have normative data from healthy controls with gender subgrouping. These tests are the exclusive tests used by practitioner members of the Institute of Evidence-Based Chiropractic.