Carpal tunnel syndrome. Testing the sensitivity and validity of four "localized discomfort" instruments.

A convenience sample of 52 participants was used to examine the construct validity and sensitivity of four "localized discomfort" instruments and the severity of clients with carpal tunnel syndrome, using the "known group" method. Three groups known to have severe, mild, or no carpal tunnel syndrome based on either nerve conduction studies or an inability to complete a physical challenge (exercise) were used. The participants rated the amount of localized discomfort for one hand, wrist, and arm on four different instruments. Following a physical challenge, strenuous enough to result in an increase in localized discomfort, the four instruments were readministered. The difference in the pre- and posttest scores was compared for both sensitivity and validity. The ease of administration of the four instruments was also assessed. All four instruments were found to demonstrate sensitivity. Two of the four instruments, the Unipolar Borg Scale and the first Visual Analog Scale, were found to be most valid and easiest to administer. Occupational health nurses could use these two valid and sensitive tools as early markers for future injury. The tools also could be used to measure the progress of an intervention or therapy following an injury and gauge readiness for return to work.