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October 1962


Author Affiliations

New England Deaconess Hospital Boston 15, Mass.

Arch Neurol. 1962;7(4):365-367. doi:10.1001/archneur.1962.04210040117015

To the Editor:  We are grateful for the interest in our paper (Motor Nerve Conduction Velocity in Diabetes, Arch. Neurol. 5:483-489, 1961) expressed by Dr. Johnson, whose own work in the field of clinical electrophysiology is well known. The opportunity to clarify the points he raises is welcome.In order to minimize the errors of instrumentation in our study, an external time signal was employed, and the stability of sweep speed was evaluated by repeated measurements from sweep to sweep and from day to day. Each biological response was paired with a time signal so that neither a dial setting nor a permanent standard was employed for measurement. The internal consistency of the oscilloscope was checked by comparing measurements of standard time interval displayed at various sweep speeds (Figure 17). Variation from sweep to sweep for a given set of observations was virtually nonexistent; maximum variation of sweep speed