EXACTNESS OF SOURCE ANALYSIS OF BIOMAGNETIC SIGNALS OF EPILEPTIFORM SPIKES BY THE METHOD OF SPATIAL-FILTERING - A COMPUTER-SIMULATION

On the basis of spatial covariance, it is found that, by spatial filte ring the localisation of a single dipole source, both parallel and per pendicular to the measurement plane (assuming a signal-noise ratio of 5:1), can be performed with an accuracy of < 0.5 mm. When the signal-n oise ratio is increased to 30:1, the resolution of temporally independ ent current sources separated by 2 mm becomes practicable. This resolu tion study is carried out by means of a pair of unity current dipoles with the dipole distance as a varying source model parameter. The conc lusions, drawn from the results of computer simulation and supported b y statistical calculations, refer to the spherical model of the volume conductor of the brain.