25 studies in the past 20 years have indicated that the current most commonly used methods of classifying validity of effort during FCE are not accurate. They have an error rate of at least 30%—-this translates to failure to detect feigned weakness, and sadly also to misclassification of cooperative persons.
In the so-called “evidence-based” FCE world, this level of error in unsatisfactory. For this reason, and possibly others, even the American Physical Therapy Association has recommended against validity or sincerity of effort testing in FCEs.
We say, “What’s the point in doing an FCE if you don’t know whether the patient is giving the best safe effort?”
There’s got to be a better way. We know there is. Here’s the short answer.
A primary study, which is the foundation for our FCE protocol, was published in 2002 in the Journal of Hand Therapy and has never been refuted or contested. It demonstrates 99.5% accuracy in classifying validity of effort during a hand strength assessment. We use standard gauges and cross-validate all the data by including simultaneous testing of both hands in the protocol.
There are seven statistically-based validity criteria that were formulated to essentially eliminate false positives—-while keeping sensitivity to feigned weakness at 99%. The odds of a cooperative person failing two of the validity criteria are 1 in 10,000 and it holds up in court. The odds of failing several criteria are exponentially higher up to 1 in 25 trillion if one should fail all seven validity criteria!
In 2010 another similar study was done, this time with a patient population, those that had pain. The results were similar and indicate that “pain” did not change the outcome of the 2002 study; feigned weakness in the upper extremities can be identified with excellent accuracy, thus lending substantial credibility when used within a FCE.
Why would anyone want to do a FCE without this important element to ensure the credibility and value of the performance data?