Reliability of single- and paired-pulse transcranial magnetic stimulation for the assessment of knee extensor muscle function.
This study examined inter-session and intra-session transcranial magnetic stimulation (TMS) reliability at two test stimulus intensities in the knee extensors. Strong and weak TMS was delivered via single- and paired- (3-ms and 100-ms inter-stimulus interval) pulses on the same day and different days. All stimuli were delivered during isometric contractions of the knee extensors at 20% of maximal voluntary force. Motor-evoked potentials (MEP) were assessed in quadriceps femoris muscles. Relative (intra-class correlation coefficient, ICC) and absolute (standard error of measurement, SEM) reliability and variability (coefficient of variation) were assessed. MEPs elicited by strong and weak single-pulse TMS had excellent relative reliability in all muscles as did weak short-interval and strong long-interval paired-pulse TMS (all ICC>0.75). Conversely, relative reliability of strong short-interval and weak long-interval paired-pulse TMS was lower (ICC: 0.34-0.83 and 0.22-0.97, respectively). MEP size variability was lower (P<0.05) and SEM comparable or lower in strong compared to weak TMS conditions. These results suggest single- and paired-pulse TMS at both strong and weak intensities are generally reliable in the knee extensors. Strong (or both strong and weak) single-pulse TMS is recommended. The results indicate using weak test pulses for short-interval and strong test pulses for long-interval paired-pulse TMS are recommended.
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
John
J
Temesi
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
Sandy N
SN
Ly
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: gmillet@ucalgary.ca.
Guillaume Y
GY
Millet
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001703:Biophysics; D004558:Electric Stimulation; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007717:Knee / Q000294:innervation*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D015203:Reproducibility of Results; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
Corticospinal excitability; Inhibition; Knee extensor; Reliability; Transcranial magnetic stimulation