Motor unit potentials with satellites in dystrophinopathies.
BACKGROUND
The objective of this study was to analyze the motor unit potentials (MUPs) with satellite components i.e., delayed by at least 2ms baseline from the main component, in the dystrophinopathies.


METHODS
The parameters of the MUPs recorded from the biceps brachii muscle in the Duchenne and Becker Muscle Dystrophy (DMD, BMD) were analyzed. The origin of the MUP satellite components was studied using a computer simulation.


RESULTS
As compared with normal potentials, both the main and the satellite MUP components are smaller in size, while the main components are more irregular. The computer simulation allows the range of muscle fiber diameters to be determined, and suggests that the variability characterizing diameters within the motor unit is responsible for generating the delayed, satellite components, via the linear relationship between the fiber diameter and the conduction velocity of the action potential.


CONCLUSIONS
The enhanced understanding of the origin of the MUP satellite components augments the knowledge about the relationship between muscle morphology and bioelectrical activity. The indirect evaluation of the range of muscle fiber diameters by means of a computer simulation may provide a new quantitative morphological data available from the EMG.
Nałęcz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland.
Ewa
E
Zalewska
Elzbieta
E
Szmidt-Salkowska
Katarzyna
K
Rowinska-Marcinska
Anna
A
Kaminska
Irena
I
Hausmanowa-Petrusewicz
D000200:Action Potentials / Q000502:physiology; D000293:Adolescent; D002648:Child; D003198:Computer Simulation; D004576:Electromyography; D006801:Humans; D009046:Motor Neurons / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology*; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology*; D009431:Neural Conduction / Q000502:physiology; D032496:Satellite Cells, Skeletal Muscle / Q000473:pathology / Q000502:physiology*; D034941:Upper Extremity / Q000503:physiopathology