ABSTRACT
INTRODUCTION: Little research has been conducted on applying the statistical estimation of the number of motor units (the MUNE statistic) in the diagnosis of neurogenic processes. AIMS: To determine the sensitivity of this test in patients with different neurogenic processes and to disseminate and clarify its basic methodological aspects. SUBJECTS AND METHODS: Both the conventional calculation and the modified version of the MUNE-Poisson put forward by Shefner et al (MUNEm) were used to carry out unilateral studies of the extensor digitorum brevis muscle in 82 patients who had previously been clinically and electromyographically diagnosed with sensory-motor axonal polyneuropathy (36 cases), unilateral L5 radiculopathy (26 patients) and second motor neuron disease (20 cases). RESULTS: Overall sensitivity of the two methods was 81.7% and 82.9%, respectively, with no significant differences between them. Similarly, the sensitivity of the MUNE studies does not differ statistically according to the diagnosis. Patients who had a compound muscle action potential (CMAP) with a reduced amplitude displayed significantly higher sensitivity in MUNE studies (94.8%) than those who exhibited a normal CMAP (69.7%) (p < 0.001). CONCLUSIONS: Although routine use of the MUNE statistical method is unnecessary in daily practice, it should be considered for use in processes in which conventional muscle electromyography, especially involving distal ones, offers doubtful results or the aim is to follow the progression of certain neurogenic processes.
Subject(s)
Action Potentials/physiology , Data Interpretation, Statistical , Electromyography , Motor Neurons/physiology , Neuromuscular Diseases/diagnosis , Neuromuscular Diseases/physiopathology , Adolescent , Adult , Child , Humans , Male , Middle Aged , Motor Neurons/cytology , Neuromuscular Diseases/surgery , Poisson Distribution , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Introducción. Existe poca experiencia sobre la aplicación de la estimación estadística del número de unidades motoras (MUNE estadístico) en el diagnóstico de procesos neurogénicos. Objetivos. Determinar la sensibilidad de dicho test en pacientes con distintos procesos neurogénicos y difundir y aclarar los aspectos metodológicos fundamentales de aquél. Sujetos y métodos. Se ha estudiado mediante MUNE-Poisson, utilizando el calculo convencional y el modificado propuesto por Shefner et al (MUNEm), unilateralmente el músculo extensor digitorum brevis de 82 pacientes previamente diagnosticados clínica y electromiográficamente de polineuropatía axonal sensitivomotora (36 casos), radiculopatía L5 unilateral (26 pacientes) y enfermedad de la segunda motoneurona (20 casos). Resultados. La sensibilidad global de ambos métodos ha sido de 81,7 y 82,9%, respectivamente, sin diferencias significativas entre ellos. La sensibilidad de los estudios MUNE tampoco es estadísticamente diferente según el diagnóstico. Los pacientes que presentaron amplitud del potencial muscular compuesto (CMAP) reducida en amplitud mostraron significativamente mayor sensibilidad en los estudios MUNE (94,8%) que los que exhibieron un CMAP normal (69,7%) (p < 0,001). Conclusión. Aunque es innecesario utilizar rutinariamente en la práctica diaria el método MUNE estadístico, sí se debe considerar su empleo en procesos en los que la electromiografía convencional de músculos, sobre todo distales, presenta resultados dudosos, o se pretende seguir la evolución de ciertos procesos neurogénicos
Introduction. Little research has been conducted on applying the statistical estimation of the number of motor units (the MUNE statistic) in the diagnosis of neurogenic processes. Aims. To determine the sensitivity of this test in patients with different neurogenic processes and to disseminate and clarify its basic methodological aspects. Subjects and methods. Both the conventional calculation and the modified version of the MUNE-Poisson put forward by Shefner et al (MUNEm) were used to carry out unilateral studies of the extensor digitorum brevis muscle in 82 patients who had previously been clinically and electromyographically diagnosed with sensory-motor axonal polyneuropathy (36 cases), unilateral L5 radiculopathy (26 patients) and second motor neuron disease (20 cases). Results. Overall sensitivity of the two methods was 81.7% and 82.9%, respectively, with no significant differences between them. Similarly, the sensitivity of the MUNE studies does not differ statistically according to the diagnosis. Patients who had a compound muscle action potential (CMAP) with a reduced amplitude displayed significantly higher sensitivity in MUNE studies (94.8%) than those who exhibited a normal CMAP (69.7%) (p < 0.001). Conclusions. Although routine use of the MUNE statistical method is unnecessary in daily practice, it should be considered for use in processes in which conventional muscle electromyography, especially involving distal ones, offers doubtful results or the aim is to follow the progression of certain neurogenic processes
