-Report on Experiments and Clinical Cases-

A New Mathematical Approach for Approximating the Baseline of F-waves Using Spreadsheet Software

Shunsuke Konno, Takafumi Aoki and Hiromoto Ito

Division for Restorative Medicine of Neuro-muscuroskeletal System, Graduate School of Medicine, Nippon Medical School

Objective: The aim of this study was to see if curved baselines of F-waves could be mathematically approximated with universal spreadsheet software.
Methods: The subjects were 3 healthy persons and 3 patients with cervical myelopathy. Supramaximal electrical stimuli were applied 200 times to the median nerve at the wrist. Compound muscle action potentials (CMAPs) of the abductor pollicis brevis were recorded. To make polynomial approximation equations that represent latter part of the M-waves, records without F-waves were analyzed.
Results: There were 193 CMAPs without F-waves out of all 1,200 records. Polynomial equations were made for each record. Determinant coefficients for all the approximation equations were greater than 0.998, and the overall standard deviation of the difference between original data and approximated value was 3.05 μV.
Conclusions: Curved baselines of F-waves were represented by approximation curves. Baselines of the F-waves could be approximated as flat lines by subtracting calculated values from the original data.
Significance: This method was useful for analyzing waveforms of F-waves.

J Nippon Med Sch 2008; 75: 274-279

Keywords
evoked potentials, regression analysis, mathematical computing

Correspondence to
Shunsuke Konno, Department of Orthopedic Surgery, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
konno@nms.ac.jp

Received, December 6, 2007
Accepted, July 23, 2008