A new method for measurement of motor unit action potential duration based on correlation, a pilot study.

We present a new, automatic, correlation-based method for measuring the duration of motor unit action potentials (MUAPs). The method seeks to replicate the way an expert elctromyographer uses his or her eyes, calculating the start and end of the MUAP waveform on the basis of the degree of similarity of non-excluded discharges. We analysed 68 potentials from normal deltoid muscles during slight contraction.

Application of a novel automatic duration method measurement based on the wavelet transform on pathological motor unit action potentials.

Objective: To evaluate a recently published automatic duration method based on the wavelet transform applied on normal and pathological motor unit action potentials (MUAPs).

Methods: We analyzed 313 EMG recordings from normal and pathological muscles during slight contractions. After the extraction procedure, 339 potentials were accepted for analysis: 68 from normal muscles, 124 from myopathic muscles, 20 from chronic neurogenic muscles, 83 from subacute neurogenic muscles and also 44 fibrillation potentials, as an example of very low duration muscular potentials.

Modelling fibrillation potentials--analysis of time parameters in the muscle intracellular action potential.

A single fiber action potential (SFAP) can be modelled as the convolution of a biolectrical source and a filter impulse response. In the Dimitrov-Dimitrova (D-D) convolutional model, the first temporal derivative of the intracellular action potential (IAP) is used as the source, and Tspl is a time parameter related to the duration of the IAP waveform. This paper is centred on the relation between Tspl and the main spike duration (MSD), defined as the time interval between the first and third phases of the SFAP.

Modeling fibrillation potentials--a new analytical description for the muscle intracellular action potential.

The single-fiber action potential (SFAP) can be modeled as a convolution of a biolectrical source (the excitation) and a transfer function, representing the electrical volume conduction. In the Dimitrov-Dimitrova (D-D) convolutional model, the first temporal derivative of the intracellular action potential (IAP) is used as the source. In this model, the ratio between the amplitudes of the second and first phases of the SFAP (which we call the PPR, after peak-to-peak ratio) increases invariably with radial distance.

A mathematical analysis of SFAP convolutional models.

In this paper we compare, from a mathematical point of view, two well-recognized single fiber action potential (SFAP) convolutional models: the Nandedkar-Stalberg (N-S) model and the Dimitrov-Dimitrova (D-D) model. Junction waves appear in N-S SFAPs due to the onset and extinction of the monopoles whereas in D-D SFAPs these waves appear only when the dipoles reach the fiber/tendon junctions. D-D junction waves model more accurately the out-of-the-main-spike waveforms that appear in experimental SFAPs.