title: Median and Ulnar 14-cm Antidromic Sensory Studies to the Third and Fifth Digits-A Comparison of Amplitude.
abstract: There are multiple reports of peripheral nerve injury following the implantation or removal of surgical hardware. Electrodiagnostic testing can be useful in assessing the chronicity, severity, and recovery of such a nerve injury. The purpose of this study is to establish a normative data set to allow for comparison of median and ulnar antidromic sensory peak-to-peak amplitude values. Median and ulnar antidromic sensory studies to digits 3 and 5 are commonly performed in electrodiagnosis to aid in the diagnosis of a variety of clinical conditions. Numerous studies have examined normal latency and amplitude values for these studies. To our knowledge there has been one other study that compared the relationship between median and ulnar sensory amplitude results taken from the same limb. That study had limited generalizability to the population at large. One hundred-nineteen volunteers were tested with antidromic sensory technique to digits 3 and 5 at 14-cm stimulation distance. Peak latency and peak-to-peak amplitude were recorded. Possible relationships between age, gender, height, weight, BMI, and median and ulnar amplitude were examined through simple linear regressions. Age, weight, height, and BMI were all found to negatively correlate with both median and ulnar amplitude. Female subjects were found to have statistically greater median and ulnar amplitudes than male subjects. Factors were said to be statistically significant at the P </= 0.05 level. The mean median peak latency was 3.2 +/- 0.3 ms. The mean ulnar peak latency was 3.2 +/- 0.4 ms. The mean median peak-to-peak amplitude was 87 +/- 36 muV. The mean ulnar peak-to-peak amplitude was 72 +/- 34 muV. The upper limit of normal difference (2.5th percentile) in median-versus-ulnar amplitude was a 56% drop from median-to-ulnar amplitude, or a 59% drop from ulnar-to-median amplitude. This allows for amplitude comparisons to be made between these two nerves.
authors.affiliation: Clinical Associate Professor & Interim Chair. Department of Physical Medicine&Rehabilitation, Indiana University School of Medicine,CL 368,541 North Clinical Drive, Indianapolis IN 46202, USA.
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Buschbacher
authors.forename: Andrew
authors.initials: A
authors.lastname: Berkson
authors.forename: Douglas
authors.initials: D
authors.lastname: Mottley
authors.forename: Zaliha
authors.initials: Z
authors.lastname: Omar