The significance of second lumbrical-interosseous latency comparison in the diagnosis of carpal tunnel syndrome.
OBJECTIVE
To assess the significance of the second lumbrical-interosseous latency (2LI-DML) comparison in the diagnosis of carpal tunnel syndrome (CTS).


METHODS
We examined 150 consecutive hands of patients referred with suspected CTS, using the 2LI-DML test and other standard measures of median nerve function. Correlations of the 2LI-DML test with standard tests were computed.


RESULTS
Hundred and four hands were electrophysiologically confirmed to have CTS. The 2LI-DML test was abnormal in 99/104 (95.2%) hands with CTS with a mean value of 1.54 +/- 1.12 ms. Among the other measures, the orthodromic median-ulnar palmar velocity comparison was the most frequently abnormal test (95/104 hands, 91.3%), followed by the double-peak morphology of orthodromic sensory action potential from digit 4 (94/104, 90.4%). The 2LI-DML test significantly correlated, either positively or negatively, with all other standard tests.


CONCLUSIONS
The 2LI-DML comparison is highly sensitive in diagnosing CTS, even in mild cases in which standard tests fail to detect abnormalities.
Argyriou
A A
AA
Department of Neurology, Saint Andrew General Hospital of Patras, Patras, Greece. andargyriou@yahoo.gr
Karanasios
P
P
Makridou
A
A
Makris
N
N
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D012680:Sensitivity and Specificity