American journal of physical medicine & rehabilitation
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Am J Phys Med Rehabil · Feb 1990
Randomized Controlled Trial Clinical TrialCan trials of physical treatments be blinded? The example of transcutaneous electrical nerve stimulation for chronic pain.
Therapeutic trials often attempt to "blind" patient and investigator to the true nature of treatments received, reducing the influences of conscious or subconscious prejudices. In drug trials, this is accomplished with placebo tablets, but blinding in trials of physical treatments is more problematic. This issue arose in a clinical trial of transcutaneous electrical nerve stimulation (TENS) for patients with chronic low back pain. ⋯ Clinicians guessed treatments correctly 61% of the time (as opposed to 50% expected by chance), again suggesting partial success in blinding. These efforts at blinding may partly explain the negative trial results for TENS efficacy. We conclude that complete blinding is difficult to achieve because of sensory difference in treatment and unintended communication between patient and examiner.(ABSTRACT TRUNCATED AT 250 WORDS)