Sensitivity, specificity, and variability of nerve conduction velocity measurements in carpal tunnel syndrome.
OBJECTIVE
To explore the diagnostic values of 8 commonly used electrodiagnostic techniques for measuring median nerve conduction velocity (NCV) in carpal tunnel syndrome (CTS).


METHODS
Sensitivity and specificity analyses.


METHODS
A hospital-based electrodiagnostic laboratory.


METHODS
Forty-four normal hands and 136 symptomatic hands.


METHODS
Not applicable.


METHODS
(1) Long-segment studies: antidromic wrist-to-digit sensory NCV without subtraction, (2) short-segment studies: transcarpal palm-to-wrist mixed NCV without subtraction, and (3) 2 segment studies: antidromic transcarpal sensory NCV with subtraction (differential calculation from wrist-to-digit and palm-to-digit segments). Both onset and peak latency values were obtained for calculating the NCV. Sensitivity, specificity, and coefficient of variance were calculated for each NCV study.


RESULTS
The short-segment, onset latency-based transcarpal mixed NCV yielded the highest sensitivity (75%).


CONCLUSIONS
Results from measurement of a single, short-nerve segment tended to be superior to results obtained by either long-segment studies or differential subtraction between 2 segments of the same nerve in the electrodiagnosis of CTS. Explanations for our results are offered from both electrophysiologic and statistical perspectives.
Lew
Henry L
HL
Physical Medicine and Rehabilitation Service, VA Palo Alto Health Care System, Palo Alto, CA 94304, USA. henrylew@stanford.edu
Date
Elaine S
ES
Pan
Steven S
SS
Wu
Peter
P
Ware
Paul F
PF
Kingery
Wade S
WS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis*; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D015588:Observer Variation; D011930:Reaction Time / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity