Abstracts

Rationale:
Paired pulse stimulation provides clinically useful information regarding sensory inhibition. As mechanomyogram (MMG) is prone to electrical noise and the sensor attachment is less time consuming than electromyogram (EMG) electrode attachment, we compared MMG and EMG to evaluate the efficacy of MMG as a tool for blink reflex early R1 component in paired pulse inhibition.

Methods:
This experiment involved eight volunteers. Participants received electrical stimulation to the supraorbital nerve of each side. A paired pulse paradigm was employed, varying the conditioning-test interval (CTI) between 5 and 800 ms. The R1 component of the induced blink reflex was recorded by MMG and EMG simultaneously using a pair of disc electrodes placed on the lower eyelid and an accelerometer placed between the electrodes, respectively.

Results:
The Pearson’s correlation coefficient of the R1 amplitude between MMG and EMG of the grand-averaged waveforms was 0.99. The average participant r value was 0.91 (range 0.76‒0.99). Similar analyses were performed for the amplitude variation of the second response relative to the first response. Results showed good correlation with r values of 0.97 and 0.86 for the grand-average waveform and the average for each subject, respectively.

Conclusions:
In contrast to EMG, MMG does not require shielded room for noise protection and attaching the sensor is can be done is short time. The present results demonstrate that MMG is a useful alternative to EMG in assessing paired-pulse inhibition of the electrical blink reflex R1 component.

Funding:
This study was supported by JSPS KAKENHI grant number 20K16684.