Single fiber electromyography: neuromuscular junction microphysiology study during reinnervation

• Grant number: 17/13262-4
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2018
• End date: April 30, 2020
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: João Aris Kouyoumdjian
• Grantee: João Aris Kouyoumdjian
• Host Institution: Faculdade de Medicina de São José do Rio Preto (FAMERP). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São José do Rio Preto , SP, Brazil

Abstract

Single fiber electromyography (SFEMG), an in-vivo neurophysiological technique, was developed in 1966 by Erik Stålberg in Sweden and is the gold-standard study for neuromuscular junction (NMJ) diseases, as in the Myasthenia Gravis. However, abnormal jitter values, although specific to junction disorders may be present in cases with axonal degeneration, followed by reinnervation, mainly in the first 6 months after the event. During this reinnervation time both axons and NMJs are immature and the neurophysiological parameters (jitter values) may be abnormally high, but not representing a primary NMJ disorder. The purpose of this study is to quantify the jitter values of the Extensor Digitorum or Tibialis Anterior muscles in patients that present axonal degeneration with on-going or chronic reinnervation. Such conditions are found in a wide conditions as in peripheral nerve injuries, amyotrophic lateral sclerosis, poliomyelitis, acute inflammatory demyelinating polyneuropathy (Guillain-Barrè syndrome) and chronic inflammatory demyelinating polyneuropathy. There are two SFEMG techniques used to measure jitter: (1) minimum voluntary contraction with activation of pairs of single fiber action potentials (SFAPs); (2) intramuscular microaxonal stimulation with activation of SFAPs. Recording is done through disposable concentric needle electrodes inserted into the studied muscle. The jitter values obtained from stimulated technique, in health subjects, is 20 to 30% less than the obtained in the voluntary technique. The excitability of immature axons and the generation of end-plate potentials also at the immature NMJs, studied by the microaxonal stimulation will be compared to the voluntary recruitment of SFAPs from immature axons and NMJs. The results obtained will help us to better understanding of the micro-physiology of immature axons and NMJs during reinnervation, not yet well-studied in the literature. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SANDERS, DONALD B.; KOUYOUMDJIAN, JOAO A.; STALBERG, ERIK V.. Single fiber electromyography and measuring jitter with concentric needle electrodes. MUSCLE & NERVE, v. N/A, p. 13-pg., 2022-06-13. (17/13262-4, 08/10082-6)

JOÃO ARIS KOUYOUMDJIAN; EDUARDO DE PAULA ESTEPHAN. Avaliação eletrofisiológica da junção neuromuscular: breve revisão. Arquivos de Neuro-Psiquiatria, v. 81, n. 12, p. 1040-1052, 2024-01-15. (17/13262-4, 22/02291-1, 08/10082-6)

KOUYOUMDJIAN, JOAO ARIS; RONCHI, LUIS GUILHERME; DE FARIA, FELIPE OLIVEIRA. Jitter evaluation in denervation and reinnervation in 32 cases of chronic radiculopathy. CLINICAL NEUROPHYSIOLOGY PRACTICE, v. 5, p. 165-172, 2020. (17/13262-4)