Impaired neuromuscular transmission in facial muscles of amyotrophic lateral sclerosis: A single‐fiber electromyography study
Background Decremental responses in repetitive nerve stimulation studies have been reported in the limb muscles of patients with amyotrophic lateral sclerosis (ALS). Aim To reveal the function of neuromuscular junction (NMJ) in the frontalis muscle, which is less affected in ALS. Methods We performe...
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Published in | Neurology and clinical neuroscience Vol. 10; no. 2; pp. 78 - 82 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Tokyo
Wiley Subscription Services, Inc
01.03.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Background
Decremental responses in repetitive nerve stimulation studies have been reported in the limb muscles of patients with amyotrophic lateral sclerosis (ALS).
Aim
To reveal the function of neuromuscular junction (NMJ) in the frontalis muscle, which is less affected in ALS.
Methods
We performed axonal‐stimulated single‐fiber EMG studies in the frontalis muscles in 27 patients with ALS, 32 with myasthenia gravis (MG), and 12 healthy controls were performed.
Results
The mean value of mean consecutive difference (MCD) in ALS was greater than controls (P < .05), but smaller than MG (P < .01) [ALS; 26.5, MG;47.7, control;16.4 (µs)]. The percentage of endplates with increased jitter (MCD >51μs) in ALS was also greater than controls (P < .001) but smaller than MG (P < .001) [ALS; 7.7, MG; 29.4, control; 0.8 (%)]. In ALS, the mean MCD was negatively correlated with the bulbar subset of ALS functional rating scale revised (ALSFRS‐R) (r = −0.67, P < .01). No axonal blocking was observed in all cohorts. In the facial muscles that are relatively preserved in ALS, jitter in single‐fiber EMG was significantly increased, possibly caused by dysfunction of the presynaptic NMJ and motor nerve terminals.
Conclusions
Assessment of neuromuscular transmission could provide a new insight into the pathophysiology of motor nerve terminal dysfunction in ALS. |
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ISSN: | 2049-4173 2049-4173 |
DOI: | 10.1111/ncn3.12580 |