A test to determine the site of abnormal neuromuscular refractoriness
| Autor: | Hugh Bostock, Peter Grafe, Hatice Tankisi |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
business.industry
Refractory period Interstimulus interval Recovery cycle Healthy subjects Neurosciences. Biological psychiatry. Neuropsychiatry Nerve excitability Refractoriness Wrist Stimulus (physiology) Cooling the nerve RCSM protocol Median nerve Neuromuscular junction medicine.anatomical_structure Neurology Physiology (medical) Anesthesia medicine Neurology (clinical) business Cooling the muscle Research Paper RC321-571 |
| Zdroj: | Tankisi, H, Bostock, H & Grafe, P 2022, ' A test to determine the site of abnormal neuromuscular refractoriness ', Clinical Neurophysiology Practice, vol. 7, pp. 1-6 . https://doi.org/10.1016/j.cnp.2021.11.001 Clinical Neurophysiology Practice, Vol 7, Iss, Pp 1-6 (2022) Clinical Neurophysiology Practice |
| ISSN: | 2467-981X |
| DOI: | 10.1016/j.cnp.2021.11.001 |
| Popis: | Highlights • A recovery cycle (RC) protocol is described with an added supramaximal stimulus (RCSM). • Unlike with conventional RC, RCSM refractoriness is unaffected by cooling the muscle. • RCSM may help to localize abnormal neuromuscular refractoriness in neuropathies. Objective The relative refractory period (RRP) of motor axons is an important parameter in nerve excitability tests of the recovery cycle (RC). Abnormalities may have a site in the axonal membrane, the neuromuscular junction, or in a dysfunction of the muscle. We aimed in this study to determine the site of abnormality, using a modified protocol of the conventional RC test, whereby an additional supramaximal stimulus is added at the same interstimulus interval as in RC recordings (RCSM). Methods Twenty-four healthy subjects aged 37.8 ± 2.4 years (mean ± SE) were examined with median nerve excitability testing using RC and RCSM protocols at normal temperature (34.1 ± 0.2 °C). The recordings were repeated in 12 subjects after selective cooling of the thenar muscle (25.2 ± 0.7 °C) and in 12 subjects after cooling the nerve trunk at the wrist (24.9 ± 0.3 °C). Results After cooling the nerve, RRP measured with RC and RCSM were prolonged similarly (medians by 1.8 ms, and 2.1 ms respectively). In contrast, cooling the muscle prolonged RRP measured with RC (by 1.3 ms), but did not significantly prolong RRP measured with RCSM. RRPs measured by RC and RCSM were significantly different when cooling was at the muscle (P = 5.10-4), but not when cooling was at the nerve (P = 0.57). Conclusions A difference between RC and RCSM indicates abnormal excitability distal to the axonal membrane under the stimulating electrode. Significance Combining RCSM with the conventional RC protocol should help to localize the site of abnormal neuromuscular refractoriness. |
| Databáze: | OpenAIRE |
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