Jornal Internacional de Neurorreabilitação

Mismatch between Correlation Coefficient and Visually Evaluation for Similarity of F-wave Waveform

Abstract

Todo M, Fukumoto Y, Tani M and Suzuki T

Objective: F-wave is one of indexes for excitability of the spinal nerve function. Our previous study suggested the change in F-wave waveform also shows the state of voluntary movement. In our previous study, we reported correlation coefficient 0.95 to one of the same criteria of the F-wave waveform. However, there were F-wave waveform that judged to be the same waveform by visual observation despite of although low C.C. In this study, we consider factors.

Methods: We measured the F-waves, presented 5 trials of 30 F-wave to 3 people. As a result of analyzing the inconstancy between judged as same waveform and C.C. of each F-wave waveform, a pairs waveforms with C.C. of less than 0.95 were analyzed.

Results: The C.C. of the waveform in a pair of waves was 0.71. The waveform shifted while visually confirming that the onset latency of matched. As a result, latency was extended 0.625 ms and C.C. improved from 0.71 to 0.96.

Conclusions: It was suggested that the C.C. shows a low value even when slight latency deviation occurs.

Significance: It is appropriate to use objective evaluation of the C.C. when judging the same waveform.