Comparison of two-point discrimination testing devices.

In order to provide hand therapists and physicians with information regarding instruments for testing two-point discrimination we evaluated 20 noninjured and 18 nerve-injured patients using the three-prong Aesthesiometer, a paper clip, and a Disk-Criminator. Two-point discrimination was tested by means of a randomized order for the two different discrimination tests and the three different testing devices. The measurement for either moving or static two-point discrimination, when obtained with the three-prong Aesthesiometer, was consistently less sensitive than with the Disk-Criminator, and the correlation coefficient was the least between these two testing devices. The Disk-Criminator measurement had the smallest standard deviation among the three testing devices. In terms of desirability of the testing device tip geometry, translation of interprong distance to numerical rating scale, and facility of alternating between one- and two-prong testing techniques, the paper clip was judged to be the least favorable and the Disk-Criminator to be the most favorable test device.