A prospective blinded evaluation of nerve conduction velocity versus Pressure-Specified Sensory Testing in carpal tunnel syndrome.
The aim of this study was to compare the sensitivity, specificity, and pain associated with nerve conduction velocity testing and a new modality, the Pressure-Specified Sensory Device, in the diagnosis of carpal tunnel syndrome. The authors evaluated 79 patients, including 26 control subjects, and made the diagnosis of carpal tunnel syndrome based on the patient's history and physical examination. Both tests were then performed on each patient. The testers were blinded to the diagnosis and to any other test results. A 0 to 10-point visual analog pain scale was used to record the patient's reported testing discomfort. The sensitivity, specificity, and mean pain scale scores were calculated for each testing modality and compared. The nerve conduction velocity test had a sensitivity of 80% and a specificity of 77% whereas the sensitivity of the Pressure-Specified Sensory Device was 91% and the specificity was 82%. The difference between the tests was not significant. There was, however, a significant difference in the pain scores: nerve conduction velocity, 2.7 points; Pressure-Specified Sensory Device, 0.9 points (p < 0.001). This study shows that the Pressure-Specified Sensory Device is as sensitive and specific as nerve conduction velocity testing in the diagnosis of carpal tunnel syndrome, and is significantly less painful for the patient.