Abstract: [Problem] It is intended to quantitatively evaluate deterioration in brain function associated with a disease such as dementia, with a high degree of accuracy by a simplified method using signals acquired from a few sensors arranged on the scalp.

Abstract: Discrete Fourier transform is performed on an output of each brain potential sensor, which measure a subject's brain potential, for each segment in order to obtain a discrete Fourier coefficient that has a frequency component. A mean value of squares of absolute values of Fourier coefficients is obtained. The Fourier coefficients are normalized using the mean value for obtaining a normalized power spectrum NPS;j,m. Mean values of squares of absolute values of Fourier coefficients of adjoining frequency components in all the segments is normalized using a square value of the mean values of the adjoining frequency components for obtaining a normalized power ratio NPV;j,m. Two markers sNAT;j,m and vNAT;j,m are derived from the power spectrum and power ratio for evaluating a brain function activity level.

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.

Abstract: The labor involved in cleaning for each examination is reduced, the examination can be carried out hygienically, and the convenience of use is improved. An electrode apparatus for detecting brain waves which is arranged in contact with the scalp and which detects brain wave signals is provided. The electrode apparatus for detecting brain waves comprises a rod-shaped electrode apparatus main body having an electrode disposed at the tip thereof, a cap which is mountable on the tip of the electrode apparatus main body and which has an elastic member which contains an electrolyte and which is disposed making close contact so as to cover the electrode, and a connection means which detachably connects the cap to the electrode apparatus main body.

Abstract: In a method and an apparatus for measuring degree of neuronal impairment in brain cortex, scalp potentials or magnetic fields of a subject are measured by mounting a plurality of sensors on a head of the subject, the measured scalp potentials or magnetic fields are converted into numerical data to obtain a dipolarity at each sampling, mean values of squared errors, within a fixed time interval, between a scalp potential or a magnetic field by an equivalent dipole at a dipolarity peak emergence time and the measured scalp potentials or magnetic fields, or variances of the squared errors from the mean values are obtained for the sensors, and a contour concerning a distribution of the mean values or the variances on a scalp or a brain surface corresponding thereto is mapped as an output. Alternatively, the squares of potentials sensed by the sensors are averaged for several seconds, and variances of these mean values are obtained for numerous reference persons.

Abstract: A proper frequency component of EEG is selected so that its scalp potential becomes smooth in a normal subject. When the brain function is impaired, non-uniformity of neuronal activity is detected in spatial as well as temporal fluctuations in the observed scalp potential of properly filtered EEG (usually the alpha component). The statistical parameters derived from dipolarity values of such a properly selected EEG component determine the state of the brain, in which whether the subject is normal or demented is judged in the early stage of dementia by comparing the obtained parameters with their threshold values. This invention presents a reliable, inexpensive, easy-to-handle and non-invasive method for sensitive screening of dementia and monitoring progress of dementia which also allows optimizing medication and treatment for dementia.

Abstract: The neuronal activity in the brain of demented subject becomes non-uniform over the cortical surface and this non-uniformity is sensitively detected by properly analyzing observed scalp potentials. The present invention is related to the computer algorithm and apparatus for numerically detecting the degree of such neuronal degeneration. A proper frequency component of EEG is selected so that its scalp potential becomes smooth in a normal subject. When the brain function is impaired, non-uniformity of neuronal activity is detected in spatial as well as temporal fluctuations in the observed scalp potential of properly filtered EEG (usually the alpha component). The statistical parameters derived from dipolarity values of such a properly selected EEG component determine the state of the brain, in which whether the subject is normal or demented is Judged in the early stage of dementia by comparing the obtained parameters with their threshold values.

Abstract: An apparatus and a method for automatically determining the present will of a human subject. The characteristic values of the subject are detected and output signals corresponding to the detected characteristic values are produced, amplified and digitized. A set of state variables for each selected frequency sub-band of a selected frequency band for each of the output signals is determined. Sets of reference weights and sets of reference biases for a neural network from sets of state reference variables corresponding to known wills are formed. Each of the sets of state variables, the sets of reference weights and the sets of reference biases are applied to the neural network to determine present will of the subject. The present will of the subject can be displayed or used to control an external device, such as a robot.

Abstract: An electrode and a method for measuring bio-electric waves are provided in which the electrode comprises a support member, a piece of absorbent fiber projecting from the support member and a non-corrosive lead coupled to the piece of absorbent fiber. Improved electrical contact between the electrode and the subject's skin is provided by allowing the piece of absorbent fiber to absorb an electrically conductive fluid.

Abstract: An apparatus and a method for automatically determining the present somatic state of a human subject. The characteristic values of the subject (e.g., scalp potential, muscle potential, heart-rate, eye-movement and frequency of eye blinks, or any combination thereof) are detected and output signals corresponding to the detected characteristic values are produced, amplified and digitized. The Fourier transformation is performed on the output signals. A set of state variables for each selected frequency sub-band of a selected frequency band for each of the output signals is determined. Sets of reference weights and sets of reference biases for a neural network from sets of state reference variables corresponding to known somatic states are formed. Each of the sets of state variables, the sets of reference weights and the sets of reference biases are applied to the neural network to determine present somatic state of the subject. The present somatic state of the subject is displayed.

Abstract: An apparatus and a method for automatically determining the present somatic state of a human subject. The characteristic values of the subject (e.g., scalp potential, muscle potential, heart-rate, eye-movement and frequency of eye blinks, or any combination thereof) are detected and output signals corresponding to the detected characteristic values are produced, amplified and digitized. The Fourier transformation is performed on the output signals. A set of state variables for each selected frequency sub-band of a selected frequency band for each of the output signals is determined. Sets of reference weights and sets of reference biases for a neural network from sets of state reference variables corresponding to known somatic states are formed. Each of the sets of state variables, the sets of reference weights and the sets of reference biases are applied to the neural network to determine present somatic state of the subject. The present somatic state of the subject is displayed.