مرکز منطقه ای اطلاع رساني علوم و فناوري - The value of fourth finger sensory median-ulnar nerve latency difference test in grading carpal tunnel sydrome

Abstract :

Purpose: Fourth finger sensory median-ulnar nerve latency difference test is a frequently used method in detecting Carpal Tunnel syndromes of especially beginning stage. The objective of this study was to show the value of fourth finger sensory median-ulnar nerve latency difference test in grading Carpal Tunnel syndrome and to find out which value second finger sensory median nerve latency should exceed in order to make a comparative study with fourth finger sensory median-ulnar nerve study.Materials and methods: If routine nerve conduction studies were normal and the fourth finger sensory medianulnar nerve latency difference was 0.5 msec and above, CTS was considered to be very mild; if only median nerve sensory latency extension (over 3.5 msec) was present CTS was considered to be mild; if in addition to median sensory latency extension there was median sensory amplitude decrease and/or median nerve motor distal latency extension, CTS was considered to be moderate. 86 women, 35 men, 189 hands with diagnosis of carpal tunnel syndrome were evaluated in this study.Results: Latency difference and age in the moderate CTS group was statistically significantly higher when compared with other groups (p 0.001). The cases whose median-ulnar sensory nerve fourth finger latency difference was 0.5 msec and the cases above this had median sensory nerve distal latency values of 3.0 msec and above.Conclusion: While 1.9 msec and above fourth finger sensory median and ulnar nerve latency difference was helpful in making a diagnosis of moderate CTS, it did not have a contribution to making very mild and mild CTS diagnosis. In addition, we recommend this test to be used in cases with CTS clinic, normal EMG examination and a median sensory latency value of 3.0 msec and over.