Conduction time for a 6-cm segment of the ulnar nerve across the elbow: reference values for the 6-cm conduction time...

Current electrodiagnostic studies for Ulnar nerve mononeuropathy at the elbow have substandard sensitivity and specificity. Reference values for a novel, screening electrodiagnostic test for ulnar nerve mononeuropathy at the elbow were obtained bilaterally from 72 subjects without any upper extremity signs or symptoms. The test used two, 3-cm straight line distances, one proximal, and one distal to the medial epicondyle to avoid a curvilinear measurement. The mean conduction times (CTE) were 1.16 +/- 0.16 milliseconds, 1.23 +/- 0.18 milliseconds, 1.33 +/- 0.24 milliseconds, for subjects 20 to 40, 40 to 60, and >60 years old, respectively. A CTE >1.50 milliseconds, >1.60 milliseconds, and >1.80 milliseconds for each age group would be considered abnormal conferring 98% specificity. The median side-to-side difference of CTE (CTE-diff) was 0.10 milliseconds with a range of 0.00 to 0.55 milliseconds. A CTE-diff >0.45 milliseconds has a specificity of 97%. Potential advantages to this method include straight-line measurement distances to reduce experimental error, and a distance less than 10 cm to improve lesion detection.