Simulated High-Density Surface Electromyographic signals for the validation of decomposition algorithms

A planar volume
conductor model was used for generating synthetic surface (sEMG) signals
(Farina and Merletti 2001). Muscle, fat and skin tissues were used in the
nonhomogeneous and anisotropic volume conductor. It included an inimitable, and
semi-infinite muscle layer with cross-section of 30 mm (transversal) × 15 mm
(depth). The average fiber length, isotropic subcutaneous and skin layer thickness
were 130 mm, 4 mm and 1 mm, respectively. Each Motor Unit (MU) had a random
number of fibers uniformly distributed between 24 and 2048 with the circular
territories of 20 fibers/mm2. The conduction velocities were
normally distributed (4.0±0.3 m/s). In the initial recruitment, each MU
discharged at 8 pulses per second (pps) (Fuglevand, Winter et al. 1993). Its
discharge rate linearly increased with excitation (0.3 pps per % of muscle
excitation). A grid of 9×10 (9 columns, 10 rows) single differential (SD) surface electrodes with 5-mm inter-electrode
distances in both directions was simulated. 15 sEMG signals with length of 16 s
were generated and sampled at 4096 Hz. Muscle excitation was set to 10%, 30%
and 50% Maximum Voluntary Contraction (MVC). The raw data was provided. It is possible to produce signals with different signal-to-noise ratios (SNRs) by adding colored
Gaussian zero-mean noise in the bandwidth of 20-500 Hz to the raw surface EMG
signals.

The signal name contains the % MVC and is a Mat-file that could
be loaded in Matlab. Each file contains the following variables:

fsampe: the Sampling rate

sig_out: the single differential (SD) sEMG signals (cell array) in rows and
columns (arbitrary units)

sFirings: the firing samples of the MUs (cell array)

References:

Farina,
D. and R. Merletti (2001). "A novel approach for precise simulation of the
EMG signal detected by surface electrodes." IEEE Transactions on
Biomedical Engineering 48(6):
637-646.

Fuglevand,
J., D. A. Winter and A. E. Patla (1993). "Models of recruitment and rate
coding organization in motor-unit pools." Journal of Neurophysiology
70(6): 2470-2488.