Objective
We measured current perception threshold (CPT) with transcutaneous electrical nerve stimulation (TENS) to prove the selective increment of the threshold of C sensory fiber and to determine onset time and duration of effect for application of TENS.

Method
TENS were applied to fifteen control volunteers for 20 minutes on hand three times per week for 2 weeks duration. The CPT was tested at the distal interphalangeal joint of the second finger with 5 Hz, 250 Hz, and 2,000 Hz in frequency, respectively. The test was repeated immediately and 30 minutes after cessation of TENS. These tests were performed on the first, eighth, and fifteenth day on application of TENS.

Results
The baseline CPT of C fiber was 32.7⁑6.4 10^⁣2 mA, Aδ fiber 23.2⁑9.4 10^⁣2 mA, and Aβ fiber 83.9⁑18.1 10^⁣2 mA. At 30 minutes after cessation of TENS in the fifteenth day, the CPT of C fiber increased markedly and that of Aδ fiber increased a little. The CPT of Aβ fiber didn't increase for 2 weeks.

Conclusion
With application of TENS, the threshold of C and Aδ fibers selectively increased, especially 30 minutes after removal of TENS application. This effect was outstanding after 2 weeks' application. (J Korean Acad Rehab Med 2002; 26: 161-166)