A Review of Clinical Quantitative Electromyography

Abstract

Information regarding the morphology of motor unit potentials (MUPs) and motor unit firing patterns can be used to help diagnose, treat, and manage neuromuscular disorders. In a conventional electromyographic (EMG) examination, a clinician manually assesses the characteristics of needle-detected EMG signals across a number of distinct needle positions and forms an overall impression of the condition of the muscle. Such a subjective assessment is highly dependent on the skills and level of experience of the clinician, and is prone to a high error rate and operator bias. Quantitative methods have been developed to characterize MUP waveforms using statistical and probabilistic techniques that allow for greater objectivity and reproducibility in supporting the diagnostic process. In this review, quantitative EMG (QEMG) techniques ranging from simple reporting of numeric MUP values to interpreted muscle characterizations are presented and reviewed in terms of their clinical potential to improve status quo methods. QEMG techniques are also evaluated in terms of their suitability for use in a clinical decision support system based on previously established criteria. Aspects of prototype clinical decision support systems are then presented to illustrate some of the concepts of QEMG-based decision making.

Clinical Measures of Disease Progression in Amyotrophic Lateral Sclerosis

“…However, needle electromyography, which is so critical in helping establish the diagnosis of ALS, is not very useful in identifying disease progression. This is because the technique is generally employed in a subjective fashion and quantitative methods are timeconsuming to perform and require considerable expertise [44].…”

Motor Unit Potential Train Validation and Its Application in EMG Signal Decomposition

“…In addition, the characteristics of an EMG signal detected from a contacting muscle are related to the anatomical and physiological features of the muscle and therefore to its age and state of health or fatigue (Stalberg & Falck, 1997;Tröger & Dengler, 2000;Fuglsang-Frederiksen, 2006;Pino et al, 2008;Farkas et al, 2010). Some parameters of EMG signals for normal and abnormal muscles are compared in Table 1.…”

“…Once the decomposition process is completed, the prototypical MUP shape (MUP template) and MU firing pattern statistics for each extracted MUPT are estimated for future analysis (especially for quantitative electromyography). This provides information, regarding the temporal behaviour and morphological layout of the MUs that significantly contributed to the detected EMG signal, which can assist with the diagnosis of various neuromuscular diseases and the study of MU control, and lead to a better understanding of healthy, pathological, ageing or fatiguing neuromuscular systems ( De Luca et al, 1982a, 1982bStalberg & Falck, 1997;Tröger & Dengler, 2000;Stashuk, 2001;Fuglsang-Frederiksen, 2006;Calder et al, 2008;Farkas et al, 2010). However, this is achieved only when this information is valid.…”

“…The purpose of EMG signal decomposition is to provide an estimate of the firing pattern and motor unit potential (MUP) template of each active motor unit (MU) that contributed significant MUPs to the EMG signal. The extracted MU firing patterns, MUP templates, and their estimated feature values can assist with the diagnosis of neuromuscular disorders (Stalberg & Falck, 1997;Tröger & Dengler, 2000;Fuglsang-Frederiksen, 2006;Pino et al, 2008;Farkas et al, 2010), the understanding of motor control ( De Luca et al 1982a, 1982bContessa et al,2009), and the characterization of MU architecture (Lateva & McGill, 2001), but only if they are valid trains. Depending on the complexity of the signal being decomposed, the variability of MUP shapes and MU firing patterns, and the criteria and parameters used by the decomposition algorithm to merge or split the obtained MUPTs, several invalid MUPTs may be created.…”

Interfaces y Sistemas en Rehabilitación y Compensación Funcional para la Autonomía Personal y la Terapia Clínica

“…En el campo del tratamiento de los trastornos neuromusculares, la práctica común incluye la evaluación de la condición del músculo por la identificación de algunos patrones en señales EMG de aguja tales como la forma del potencial de acción de unidad motora (PAUM). Esta evaluación subjetiva es altamente dependiente de las habilidades y nivel de experiencia del médico, y es propenso a una alta tasa de error y el sesgo del operador (Farkas et al, 2010). Además, como es doloroso, invasivo y requiere especialistas altamente cualificados, no se recomienda para ser utilizado en el entorno de rehabilitación (Lauer et al, 2007).…”