Dr Radoff's concerns about the accuracy and reproducibility of our conduction technique are understandable. Regarding the location of the recording electrode, this is standardized at 3 cm proximal to the metacarpophalangeal joint of the fifth finger; however, hands will, of course, vary in size, making the actual anatomical location of the recording electrode slightly different. Regarding the location of the site of stimulation, the 2- to 3-cm variability of location is to some extent unavoidable, since the dorsal cutaneous branch of the ulnar nerve arises at a variable distance proximal to the ulnar styloid process.1The lack of an absolutely constant interelectrode distance does make for a greater degree of inaccuracy when comparing latency values; therefore, we would place greater value on conduction velocity values, as well as the presence or absence of a recordable nerve action potential. We would also stress the necessity of very careful measurement of the
Kim D, Wainapel SF, Kalantri A, Guha S. Dorsal Cutaneous Ulnar Nerve Conduction-Reply. Arch Neurol. 1982;39(1):67–68. doi:10.1001/archneur.1982.00510130069026
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