Evaluation of two-point discrimination in children: reliability, effects of passive displacement and voluntary movements.

Two-point discrimination (2-PD) thresholds were studied at three sites (tip of index finger, thenar eminence, external malleolus) and under various testing conditions (dynamic vs static, with and without displacement of instrument on skin; and active vs passive, with and without voluntary movement of subject) in 47 healthy children between 6 and 13 years of age. Reliability was fair to moderate, with slightly better perception (learning effect) during the second testing session. The threshold values of these children were similar to those of adults. For the passive conditions, the threshold values were lower for dynamic than for static tests at all sites. For the active condition at the index finger, there were no differences between dynamic and static values and there was no active/passive main effect. It is concluded that: (1) the hand is more sensitive than the ankle, with the finger being the most sensitive area, (2) the 2-PD test procedure used was most reliable at the index finger and least reliable at the external malleolus and (3) displacement of the instrument on the skin can improve 2-PD threshold values in children but the discrimination thresholds are not changed by active movement of the subject.