Objective:To estimate jitter parameters in myasthenia gravis in stimulated frontalis and extensor digitorum muscles using the concentric needle electrode.Methods:Forty-two confirmed myasthenia gravis patients, being 22 males (aged 45.6±17.2 years-old) were studied. Jitter was expressed as t...

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Bibliographic Details
Main Authors: João Aris Kouyoumdjian, Erik Stålberg
Format: Article
Language:English
Published: Thieme Revinter Publicações 2013-04-01
Series:Arquivos de Neuro-Psiquiatria
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-282X2013000400237
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Summary:Objective:To estimate jitter parameters in myasthenia gravis in stimulated frontalis and extensor digitorum muscles using the concentric needle electrode.Methods:Forty-two confirmed myasthenia gravis patients, being 22 males (aged 45.6&#177;17.2 years-old) were studied. Jitter was expressed as the mean consecutive difference (MCD). Results: MCD in extensor digitorum was 61.6 &#181;s (abnormal in 85.7%) and in frontalis 57.3 &#181;s (abnormal in 88.1%). Outliers represented 90.5% for extensor digitorum and 88.1% for frontalis. At least one jitter parameter was abnormal in 90.5% of the combined studies. Acetylcholine receptor antibody was abnormal in 85.7% of the cases. Conclusions:Stimulated jitter recordings measured from muscles using concentric needle electrode can be used for myasthenia gravis diagnosis with high sensitivity. Extensive normative studies are still lacking and, therefore, borderline findings should be judged with great caution.<br>Objetivo:Mensurar os valores do jitter em pacientes com miastenia gravis nos m&#250;sculos frontalis e extensor digitorum pela t&#233;cnica estimulada, utilizando-se eletrodo de agulha conc&#234;ntrica.M&#233;todos:Foram estudados 42 pacientes, sendo 22 homens (idade 45,6&#177;17,2 anos), com miastenia gravis confirmada. O jitter foi expresso como a m&#233;dia das diferen&#231;as consecutivas (MDC).Resultados: A MDC para o extensor digitorum foi 61,6 &#181;s (anormal em 85,7%) e para o frontalis 57,3 &#181;s (anormal em 88,1%). Outliers representaram 90,5% para o extensor digitorum e 88,1% para o frontalis. Pelo menos um par&#226;metro do jitter foi anormal em 90,5% dos estudos combinados. Anticorpo receptor de acetilcolina estava anormal em 85,7% dos casos. Conclus&#245;es:Jitter estimulado mensurado por meio de eletrodo de agulha conc&#234;ntrica pode ser utilizado para diagn&#243;stico de miastenia gravis com elevada sensibilidade. Estudos normativos mais amplos ainda s&#227;o necess&#225;rios e, portanto, valores lim&#237;trofes devem ser avaliados com cautela.
ISSN:0004-282X
1678-4227