Objective: In clinical electromyography, motor unit potential(MUP) size is use d to indicate the myo-or neurogenic origin of the pathological process, whereas the irregularity of MUP shape is considered not useful in ...Objective: In clinical electromyography, motor unit potential(MUP) size is use d to indicate the myo-or neurogenic origin of the pathological process, whereas the irregularity of MUP shape is considered not useful in this respect. The aim of the present study was to find a method to improve classification of MUPs usi ng a combined analysis of the size and irregularity of the potential. Methods: T he records with at least 20%of irregular potentials from 14 healthy subjects an d 34 patients were analysed. Principal Component Analysis (PCA) was applied in t he analysis of data to find a linear function combining the size and the irregul arity of a MUP. Results: The linear combination of size and irregularity measure s, i.e. size index (SI) and irregularity coefficient (IR) obtained using Princip al Component Analysis (PCA) did not increase the discriminating ability incompar ison to SI.We have defined a non-linear function of the SI and IR called SIIR, which modifies SI values for irregular potentials only. Its discriminating abili ty is higher than that of SI. Conclusions: By combined assessment of the size of a MUP and its irregularity, the differentiation between neurogenic and myopathi c potentials could be considerably improved. Significance:The proposed coefficie nt SIIR seems to be more discriminating than others presently used. When applied in clinical studies it may be useful in the evaluation of confusing,atypical mo tor unit potentials.展开更多
Objective: Motor unit potential (MUP) morphology can bequantified using parame ters describing electrophysiological size and shape (complexity). Traditionally, MUP complexity has been estimated using parameters number...Objective: Motor unit potential (MUP) morphology can bequantified using parame ters describing electrophysiological size and shape (complexity). Traditionally, MUP complexity has been estimated using parameters number of phases and turns. Recently, ‘irregularity coefficient’(IR), measuring the length of the MUP curv e normalized with its amplitude, has been introduced. The aim of this study was to evaluate IR in the external anal sphincter muscle. Methods: Sensitivity was e xamined in 61 patients with chronic cauda equina lesions, and specificity in 75 controls using a standard concentric EMG needle and EMG system with multi-MUP a nalysis. Results: When evaluated separately the sensitivity of IR was 16%lower, and specificity 5%higher compared to number of turns, with both differences de creasing to only 2 and 1%, respectively, when each of these parameters was adde d to MUP area and duration.Conclusions: Our present results suggest that IR prov ides a similar diagnostic usefulness, but a more appropriate description of MUP complexity compared to traditional MUP parameters.Significance: IR seems to be s uitable to complement one of MUP parameters measuring electrophysiological MUP s ize in the future quantitative EMG.展开更多
文摘Objective: In clinical electromyography, motor unit potential(MUP) size is use d to indicate the myo-or neurogenic origin of the pathological process, whereas the irregularity of MUP shape is considered not useful in this respect. The aim of the present study was to find a method to improve classification of MUPs usi ng a combined analysis of the size and irregularity of the potential. Methods: T he records with at least 20%of irregular potentials from 14 healthy subjects an d 34 patients were analysed. Principal Component Analysis (PCA) was applied in t he analysis of data to find a linear function combining the size and the irregul arity of a MUP. Results: The linear combination of size and irregularity measure s, i.e. size index (SI) and irregularity coefficient (IR) obtained using Princip al Component Analysis (PCA) did not increase the discriminating ability incompar ison to SI.We have defined a non-linear function of the SI and IR called SIIR, which modifies SI values for irregular potentials only. Its discriminating abili ty is higher than that of SI. Conclusions: By combined assessment of the size of a MUP and its irregularity, the differentiation between neurogenic and myopathi c potentials could be considerably improved. Significance:The proposed coefficie nt SIIR seems to be more discriminating than others presently used. When applied in clinical studies it may be useful in the evaluation of confusing,atypical mo tor unit potentials.
文摘Objective: Motor unit potential (MUP) morphology can bequantified using parame ters describing electrophysiological size and shape (complexity). Traditionally, MUP complexity has been estimated using parameters number of phases and turns. Recently, ‘irregularity coefficient’(IR), measuring the length of the MUP curv e normalized with its amplitude, has been introduced. The aim of this study was to evaluate IR in the external anal sphincter muscle. Methods: Sensitivity was e xamined in 61 patients with chronic cauda equina lesions, and specificity in 75 controls using a standard concentric EMG needle and EMG system with multi-MUP a nalysis. Results: When evaluated separately the sensitivity of IR was 16%lower, and specificity 5%higher compared to number of turns, with both differences de creasing to only 2 and 1%, respectively, when each of these parameters was adde d to MUP area and duration.Conclusions: Our present results suggest that IR prov ides a similar diagnostic usefulness, but a more appropriate description of MUP complexity compared to traditional MUP parameters.Significance: IR seems to be s uitable to complement one of MUP parameters measuring electrophysiological MUP s ize in the future quantitative EMG.
