Evaluation of motor endplate functions with single fiber electromyography in patients with migraine

INTRODUCTION: Migraine is a common headache disorder that is widespread, recurrent, mostly unilateral, severe, throbbing and cause temporary disability. There are basically 2 types of migraine with and without aura. The common forms of migraine have previously been demonstrated by the single-fiber electromyography (SFEMG) method in which neuromuscular transmission is abnormal in migraine with and without aura. SFEMG is the best and safest electrophysiological method to evaluate in vivo neuromuscular junction performance in human subjects. In our study, we aimed to show whether the subclinical neuromuscular transmission was affected in the motor end plate due to possible underlying canalopathy in P/Q type calcium channels in different migraine types with migraine patients, to confirm the results of previous studies and to understand the pathophysiology of migraine. MATERIALS AND METHODS: 25 healthy volunteers (19 females 6 males) aged between 18-55 years old, 30 migraine patients without aura (26 females 4 males, 30 migraine patients without aura (28 female and 2 male) ) that diagnosed according to the criteria determined by the International Headache Society (IHS) in 2013, similar age range with control group, total of 85 people were included in the study. Disability status of migraine patients included in the study was evaluated by Migraine Disability Assesment Scale (MIDAS) and pain severity by Numeric Pain Rating Scale (NRS). Voluntary TLEMG was performed from the frontalis muscle to the patients and healthy volunteers. The mean individual jitter values ​​of the migraine group, the number of fibers with increased jitter, mean MCD (Mean Consecutive Difference), lowest and highest jitter values ​​were compared with the control group. Motor end plate functions were interpreted according to the number of fibers recorded from individuals and increased jitter. Accordingly, in the case that all recorded jitter values ​​were normal or 1 was above 55 microseconds, the motor end plate functions were considered normal. In patients with 2 more than 55 microseconds of 20 jitter values, there was a borderline defect in the motor end plate functions, and in patients with an elevation of 3 or more, the motor end plate function was considered to be defective and analyzed accordingly. RESULTS: The total number of patients was 60. Among these, 5 of 30 patients with migraine with aura had neuromuscular conduction disorder, 8 had neuromuscular conduction disorder, and 17 had normal. Neither 30 patients with a migraine without aura and 25 of the control group had no neuromuscular conduction disorder (3 had borderline disorder, 27 were normal). In our study, the highest jitter values ​​of migraine patients were found to be higher when the highest jitter mean values ​​of the patients in the control group and migraine patients were compared. In addition, the average MCD values ​​of individuals with aura are higher than those without aura and controls. DISCUSSION: These findings suggest that migraine patients with aura and without aura have a tendency to abnormal motor end-plate functions compared to controls in the migraine group compared to healthy controls. Although there is a common evidence that migraine is a polygenetic and multifactorial disease, the pathogenesis of migraine has still not been fully elucidated. Clinical features, genetic and environmental factors, and possibly neurophysiological tests will be informative to reveal the pathogenesis. The neuromuscular conduction disorder detected by SFEMG may also be effective in identifying the phenotype of migraine patients who are candidates for further genetic testing, as well as treatment selection. As a result, in this study which is performed by voluntary SFEMG from frontalis muscle, compared than other studies in literature, in migraine, especially in migraine with aura, than migraine without aura and patients with migraine without any aura there is a tendency to disorder in motor end plate functions compared to the control group and the idea of that this may be due to a genetical susceptibility channelopathies has been supported. Keywords: jitter, mean consecutive difference, migraine, neuromuscular transmission, single-fiber electromyography