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Published on: August 14, 2021
Function of the Normal Neuromuscular Junction in Young Children
Márk Kozák1, Katalin Szatmári2, Erzsébet Németh2
1Department of Neurology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
Insights
Repetitive nerve stimulation (RNS) testing in young children shows normal amplitude decrement but potentially higher area decrement. Further studies are needed to understand neuromuscular junction function in pediatric patients.
Area of Science:
- Neurology
- Pediatric Medicine
- Neurophysiology
Background:
- Repetitive nerve stimulation (RNS) is crucial for assessing neuromuscular junction integrity.
- Limited RNS data exists for newborns and young children, hindering early diagnosis of neuromuscular diseases.
Purpose of the Study:
- To conduct RNS in young children to establish normative data.
- To investigate age-related changes in RNS parameters in pediatric populations.
Main Methods:
- RNS of the axillary nerve was performed in 34 healthy children aged 0-48 months under sedation.
- Compound muscle action potentials (CMAPs) were recorded from the deltoid muscle.
- Analyzed CMAP amplitude and area decrement, post-tetanic facilitation, and twitch-to-tetanus ratio.
Main Results:
- CMAP amplitude decrement was generally within adult normal ranges (median 1%).
- CMAP area decrement showed a positive correlation with age, exceeding 10% in infants under 6 months.
- Post-tetanic facilitation and twitch-to-tetanus ratio also correlated positively with age.
Conclusions:
- While CMAP amplitude decrement is comparable to adults, CMAP area decrement may differ in young children.
- Further research on RNS in other nerves and in unsedated children is warranted.
Introduction/Aims:
The repetitive nerve stimulation (RNS) test is fundamental to test the functional integrity of the neuromuscular junction. RNS data are scarce for newborns and young children, limiting early diagnostic efforts to identify children with neuromuscular diseases. Here, we performed RNS in young children.
Methods:
RNS of the axillary nerve was performed in 34 otherwise healthy young children (0 to 48 months of age) undergoing procedural sedation or analgesia. Compound muscle action potentials (CMAP) were recorded over the deltoid muscle. CMAP amplitude and area decrement between the 1st and 4th potential were determined at 3 Hz stimulation. Post-tetanic facilitation, twitch-to-tetanus ratio, and heart rates were recorded.
Results:
The largest CMAP amplitude decrement value was 7% at rest, having a median of 1%, and an interquartile range of 1%-3%. There was no correlation between the CMAP amplitude decrement and age. In contrast, a moderate positive correlation was found between the CMAP area decrement and age, occasionally exceeding 10% in infants younger than 6 months. Both post-tetanic facilitation and twitch-to-tetanus ratio exhibited a moderate positive correlation with age.
Discussion:
While the CMAP amplitude decrement in young children was within the adult normal range, the area decrement may be higher. Studies of RNS on other nerves in unsedated children are needed to investigate the findings from this study further.
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