J Korean Acad Rehabil Med.  1997 Feb;21(1):200-204.

The Effect of Thumb Position on Median-Radial Latency Difference

• Kim HW
• Cho EJ
• Ko YJ
• Kang SY

Abstract

In diagnosis of carpal tunnel syndrome, there are many techniques with high sensitivity Among them, the median-radial latency difference(MRLD) is one of the most useful technique in screening mild carpal tunnel syndrome w ith high sensitivity, no painful discomfort to patients and no motor artifact. In this study, we examined the effect of the thumb position (radial abduction and adduction) on the MRLD. Because the stimulation sites of the median sensory and superficial radial nerves are different from each other, the free movement of the thumb in this examinations is not avoidable. The results are 1) there is no significant effect of the thumb position on median sensory latency. 2) There is no significant effect of the thumb position on superficial radial latency. 3) There is significant effect of the thumb position on MRLD(P<0.01). Therefore, if we diagnose the mild carpal tunnel syndrome with MRLD, the thumb position must be maintained in neutral position through the examination.

Keyword

carpal tunnel syndrome; median-radial latency difference (MRLD); thumb position

MeSH Terms

Artifacts
Carpal Tunnel Syndrome
Diagnosis
Humans
Mass Screening
Radial Nerve
Thumb*