Related Experiment Video
Updated: May 5, 2026
EEG Mu Rhythm in Typical and Atypical Development
Published on: April 10, 2014
Discrimination of spontaneous activity in needle EMG based on the quantitative assessment of the discharge rhythm
Taiji Mukai1, Takamichi Kanbayashi1, Masahito Kobayashi2
1Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan.
Objective:
Discrimination between EMG activity such as fibrillation potentials/positive sharp waves (Fib/PSW), end plate spikes (EPS), fasciculation potentials (FP), and contaminating voluntary motor unit potentials (MUP) is mandatory for EMG diagnosis. Discharge rhythm is the key for discrimination. We devised a new parameter, Random Index (RI), which quantifies the rhythm and takes a value from 0 to 1, smaller for regular trains of discharges. This study evaluated the utility of RI as well as modified versions of the regularity indices proposed in past reports.
Methods:
EMG records of patients with amyotrophic lateral sclerosis were retrospectively reviewed. EPS were collected also from a healthy volunteer. The EMG activity was classified by an expert. RI and other regularity indices as well as the median instantaneous firing rate (IFRm) were calculated.
Results:
Analyzed sequences were 73 Fib/PSW, 27 EPS, 24 FP, and 36 MUP. The four types were clearly separated over the 2-dimensional plots of regularity indices vs. IFRm. Especially, Fib/PSW and EPS were far separated in these plots. RI achieved significantly better discrimination between Fib/PSW and MUP than other indices.
Conclusion:
RI is a robust tool for discriminating EMG activity.
Significance:
RI and other regularity indices would be useful for educational purpose.
