Analysis of electrical activity in healthy and dystrophic muscle in man

Willison, R. G.

doi:10.1136/jnnp.27.5.386

Cited by 190 publications

(75 citation statements)

References 10 publications

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“…'Turns analysis' has not been previously used in CP studies, but has been extensively used in clinical studies (Willison 1964, Fulsang-Frederiksen 1981, Liguori et al 1992. It provides information on the spatial and temporal summation of action potentials (Fulsang-Frederiksen 1981).…”

Section: Discussionmentioning

confidence: 99%

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Contributing factors to muscle weakness in children with cerebral palsy

Elder

BSc

Cook

et al. 2003

Develop Med Child Neuro

228

111

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The aim of this study was to determine the extent of ankle muscle weakness in children with cerebral palsy (CP) and to identify potential causes. Maximal voluntary contractions of plantar (PF) and dorsiflexors (DF) were determined at optimal angles in knee flexion and extension in both legs of 14 children with hemiplegia (7 males, 7 females) and 14 with diplegia (8 males, 6 females). Their results were compared to 14 age‐ and weight‐matched control participants (5 males, 9 females). Muscle cross‐sectional areas of soleus, posterior, and anterior compartment muscles were determined from MRIs in 14 children with CP (eight diplegia, six hemiplegia) and 18 control children. Specific tension (torque/unit area) of PF and DF was determined from torque and cross‐sectional area results. Muscle volumes of PF and DF were also determined in both legs of five control children and five with hemiplegia. Muscle EMG was recorded from soleus, medial gastrocnemius, and tibialis anterior during each maximal voluntary contraction. Mean amplitude was significantly reduced in PF and DF in both CP groups and significantly higher levels of coactivation of antagonists were found compared to control participants. Strength of PF and DF was significantly reduced in both CP groups, but more importantly the muscles were found to be weak based on significantly reduced specific tensions. The PF were most affected, particularly in the group with hemiplegia. It is believed that an inability to maximally activate their muscles contributed to this weakness. A combination of incomplete activation and high levels of PF coactivation are thought to have contributed to DF weakness.

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Section: Discussionmentioning

confidence: 99%

“…The EMG interference pattern was analyzed using a technique called 'turns analysis'. It was first described by Willison (1964), and has been extensively used in clinical studies (see Liguori et al 1995). The number of 'turns' recorded during a contraction is dependent on the number of active motor units and their firing frequencies.…”

Section: Methodsmentioning

confidence: 99%

Contributing factors to muscle weakness in children with cerebral palsy

Elder

BSc

Cook

et al. 2003

Develop Med Child Neuro

228

111

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“…The number of zero crossings of 100 µV or more per time unit increased with increasing submaximal force up to 40% to 60% of MVC and thereafter leveled off. 29, 35 Willison 207 found that the number of turns per time unit increased with force up to 2 kg in the brachial triceps muscle, corresponding to 12% to 30% of MVC. Later studies showed that the number of turns per time unit increased up to about 50% of MVC and above that leveled off (Fig.…”

mentioning

confidence: 99%

The utility of interference pattern analysis

Fuglsang-Frederiksen

2000

Muscle Nerve

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“…La mayoría de los equipos actuales cuentan con conversores de 16 bits, con lo cual se pueden obtener medidas del orden de nanovoltios metros. La actividad durante el máximo esfuerzo puede analizarse cuantitativamente midiendo el número y amplitud de los picos (giros) presentes en la señal con diferentes algoritmos, algunos ya implementados en los primeros sistemas modulares, como el analizador de Willison (Tabla 2) 9 . En lo que respecta al análisis de la FO del PAUM, los aparatos convencionales cuentan con algoritmos para determinar los puntos inicial y final de la curva (y la duración como la diferencia de tiempo entre ambos), la amplitud máxima (diferencia entre las muestras de menor y mayor valor), el área bajo la curva, el número de fases (partes de la curva a uno y otro lado de la línea de base) y el número de giros (cambios de dirección de la curva) ( Fig.…”

Section: Digitalizaciónunclassified

Electromyographic signal processing and analysis methods

Gila

Malanda

Carreño³

et al. 2010

An Sist Sanit Navar

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RESUMENLa electromiografía clínica es una metodología de registro y análisis de la actividad bioeléctrica del músculo esquelético orientada al diagnóstico de las enfermedades neuromusculares. Las posibilidades de aplicación y el rendimiento diagnóstico de la electromiografía han evolucionado paralelamente al conocimiento de las propiedades de la energía eléctrica y al desarrollo de la tecnología eléctrica y electrónica. A mediados del siglo XX se introdujo el primer equipo comercial de electromiografía para uso médico basado en circuitos electrónicos analógicos. El desarrollo posterior de la tecnología digital ha permitido disponer de sistemas controlados por microprocesadores cada vez más fiables y potentes para captar, representar, almacenar, analizar y clasificar las señales mioeléctricas. Es esperable que el avance de las nuevas tecnologías de la información y la comunicación pueda conducir en un futuro próximo a la aplicación de desarrollos de inteligencia artificial que faciliten la clasificación automá-tica de señales así como sistemas expertos de apoyo al diagnóstico electromiográfico.Palabras clave. Electromiografía. Potencial de acción de unidad motora. Procesamiento de señal. Estudios neurofisiológicos. ABSTRACTClinical electromyography is a methodology for recording and analysing the bioelectrical activity of the skeletal muscle tissue in order to diagnose neuromuscular pathology. The possibilities of application and the diagnostic performance of electromyography have evolved parallel to a growing understanding of the properties of electricity and the development of electrical and electronic technology. The first commercially available electromyography equipment for medical use was introduced in the middle of the 20th century. It was based on analog electronic circuits. The subsequent development of digital technology made available more powerful and accurate systems, controlled by microprocessors, for recording, displaying, storing, analysing, and classifying the myoelectric signals. In the near future, it is likely that advances in the new information and communication technologies could result in the application of artificial intelligence systems to the automatic classification of signals as well as expert systems for electromyographic diagnosis support.

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Analysis of electrical activity in healthy and dystrophic muscle in man

Cited by 190 publications

References 10 publications

Contributing factors to muscle weakness in children with cerebral palsy

Contributing factors to muscle weakness in children with cerebral palsy

The utility of interference pattern analysis

Electromyographic signal processing and analysis methods

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