Evaluation of mechanomyogram efficacy as a tool for assessing paired‐pulse inhibition of blink reflex early R1 component

• Published in: Muscle & nerve Vol. 70; no. 2; pp. 279 - 283
• Main Authors: Bayasgalan, Borgil, Itoh, Yasushi, Shingaki, Megumi, Inui, Koji
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.08.2024; Wiley Subscription Services, Inc
• Subjects: Accelerometers; Amplitudes; Blink reflex; conditioning‐test interval; Correlation coefficient; Correlation coefficients; Electrical stimuli; Electrodes; Electromyography; EMG; Eyelid; MMG; Nerves; Paired-pulse inhibition; Paired-pulse stimulation; R1 component; Sensory evaluation; Stimulation; Waveforms; conditioning‐test interval; paired‐pulse inhibition; MMG; R1 component; EMG
• ISSN: 0148-639X; 1097-4598; 1097-4598
• DOI: 10.1002/mus.28172

Introduction/Aims Paired‐pulse stimulation provides clinically useful information regarding sensory inhibition. When supraorbital nerve stimulation is repeated within a short interval, the response to the second stimulation is reduced to varying degrees. This magnitude of change in stimulation response can be monitored by electromyogram (EMG) or by mechanomyogram (MMG) as in this report. MMG has some advantages such as being less time consuming and lacking stimulus artifact. We compared the use of MMG and EMG to validate MMG as an effective method of assessing blink reflex paired‐pulse inhibition. Methods Eight volunteers participated. Participants received electrical stimulation to the supraorbital nerve of each side. A paired‐pulse paradigm was employed, varying the conditioning‐test interval between 5 and 800 ms. The R1 component of the induced blink reflex was simultaneously recorded by EMG using a pair of electrodes placed on the lower eyelid and by MMG using an accelerometer placed between the electrodes. Results The correlation coefficient of the R1 amplitude between MMG and EMG of the grand‐averaged waveforms was 0.99. The average participant r value was .91 (range .76–.99). Similar analyses were performed for the amplitude variation of the second response relative to the first response. Results correlated well, yielding r values of .97 and .86 for the grand‐averaged waveform and the average for each subject. Discussion The present results demonstrate that MMG could be an alternative to EMG in assessing paired‐pulse inhibition of the electrical blink reflex R1 component.