Does change in neuromuscular jitter predict or correlate with clinical change in MG?

INTRODUCTION

The objective of this study was to determine if single-fiber electromyography (SFEMG) jitter accurately reflects change in severity in myasthenia gravis (MG).

METHODS

We reviewed jitter and outcome data from all MG patients in our clinic who had at least 2 jitter measurements in the extensor digitorum or frontalis muscle.

RESULTS

Change in all parameters of jitter measured with SFEMG electrodes predicted clinical change with acceptable accuracy. Absolute and percentage change in mean value of consecutive interval differences were equally accurate in predicting clinical change and were more accurate than change in the proportion of fiber pairs with blocking or normal jitter.

CONCLUSIONS

Jitter is a sensitive measure of severity in MG and has a potential role as a biomarker in clinical trials and the clinic. Absolute or percentage change in mean jitter is the best jitter parameter to follow. The accuracy of change in jitter measured with other electrodes has yet to be determined. Muscle Nerve 56: 45-50, 2017.