Abstract: 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.

Abstract: For measuring a brain local activity, a predetermined frequency bandwidth wider than a frequency bandwidth of alpha waves of scalp potentials is divided into a predetermined number of frequency banks each having a fixed frequency width, data of each divided frequency bank is divided into segments of a predetermined duration on a time axis, a Z-score of the subject is determined from a first mean value of normalized power variances determined for the segments and a second mean value of normalized power variances predetermined in the same manner as the first mean value for a predetermined normal person group and a standard deviation of the normalized power variances in the group, and a mean value of the Z-scores determined over all of the frequency banks is mapped on a brain surface for each sensor, whereby a template of a specified brain disorder and likelihood of a subject to a specified brain disorder are calculated.

Abstract: For measuring a brain local activity, a predetermined frequency bandwidth wider than a frequency bandwidth of alpha waves of scalp potentials is divided into a predetermined number of frequency banks each having a fixed frequency width, data of each divided frequency bank is divided into segments of a predetermined duration on a time axis, a Z-score of the subject is determined from a first mean value of normalized power variances determined for the segments and a second mean value of normalized power variances predetermined in the same manner as the first mean value for a predetermined normal person group and a standard deviation of the normalized power variances in the group, and a mean value of the Z-scores determined over all of the frequency banks is mapped on a brain surface for each sensor, whereby a template of a specified brain disorder and likelihood of a subject to a specified brain disorder are calculated.