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: 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.
