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Sensitive median–ulnar motor comparative techniques in carpal tunnel syndrome
Author(s) -
Sander Howard W.,
Quinto Christine,
Saadeh Peter B.,
Chokroverty Sudhansu
Publication year - 1999
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199901)22:1<88::aid-mus13>3.0.co;2-c
Subject(s) - carpal tunnel syndrome , wrist , median nerve , medicine , ulnar neuropathy , carpal tunnel , ulnar nerve , latency (audio) , concomitant , significant difference , surgery , polyneuropathy , elbow , electrical engineering , engineering
We describe two modified methods for median‐to‐ulnar motor conduction comparison in the diagnosis of median neuropathy at the wrist: the median–thenar to ulnar–thenar latency difference (TTLD), and the median–thenar to ulnar–hypothenar latency difference (THLD). We also describe an F‐wave ulnar‐to‐median comparative test, the F‐wave latency difference (FWLD). The abnormal cutoffs based upon 34 normal controls are: TTLD, 0.8 ms; THLD, 1.2 ms; FWLD, 0.6 ms. In 50 patients (79 hands) with clinically defined carpal tunnel syndrome and electrophysiological evidence of median neuropathy at the wrist (based upon a prolonged median nerve palm–wrist latency), the diagnostic sensitivities were: 95–98%, 85–88%, and 75–78%, respectively. These tests are therefore highly sensitive. They are easily performed and require minimal additional effort to incorporate into commonly used clinical electrodiagnostic routines. They may be advantageous when a concomitant polyneuropathy is present, and they may also help avoid technical pitfalls and aid in identification of anatomic variants. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 88–98, 1999