Median mixed and sensory nerve conduction studies in carpal tunnel syndrome.
OBJECTIVE
To assess the sensitivities and specificities of velocity differences between median mixed nerve conduction across the wrist (Medmxpw) and (I) median mixed nerve conduction in the forearm (Medmxf) and (II) palm to D2 sensory conduction (MedpD2).


METHODS
We prospectively studied 67 limbs of patients with clinically definite carpal tunnel syndrome (CTS). Medmxf and Medmxpw were performed by stimulating the median nerve at the elbow and palm respectively and recording at the proximal wrist crease. We also compared conventional median sensory (D2-wrist) and mixed (palm-wrist) tests in all patients. Thirty limbs of asymptomatic subjects served as normal controls and 21 limbs of subjects with other neuropathies served as diseased controls; control data was collected prospectively.


RESULTS
The sensitivity of the MedpD2-Medmxpw difference (0.87) was significantly greater than that of the Medmxf-Medmxpw difference (0.61, P < 0.001). Both tests were similar and highly specific (0.98 and 0.96, respectively).


CONCLUSIONS
The MedpD2-Medmxpw study is among the most sensitive and specific electrophysiologic tests for CTS.
Scelsa
S N
SN
Department of Neurology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA.
Herskovitz
S
S
Bieri
P
P
Berger
A R
AR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D011446:Prospective Studies