摘要 |
A magnitude of a current component in x direction, y direction or z direction, or a composite current of the current components in x direction, y direction and z direction, estimated from scalp potentials outputted from sensors mounted on a head of a subject, predetermined coordinates of lattice points preset in a standard brain, and predetermined coordinates of the sensors is determined. A normalized power variance (NPV) and its mean value are determined with Fourier coefficients determined from the magnitude of the current component or the composite current. Z-score (or Y-score) of the subject from a mean value of NPV predetermined in the same manner as the mean value and a standard deviation of the NPV for a predetermined normal person group is determined and mapped with contour lines corresponding to the lattice points on a horizontal plane designated. |