Abstract: A system (2) for evaluating the efficiency of therapeutic treatments of patients (40) located at remote sites (6) by communicating a cognitive task to the remote site via a network (10) which provides two-way communication between a central analysis site and the remote sites, presenting the task to the patient before, during, or after carrying out a therapeutic intervention or treatment, detecting brain response from the patient, and communicating this response to the central analysis site via the network.

Abstract: A mass communication assessment system (2) communicating a cognitive task to selected remote test sites (12) via a network (10) for providing a two-way communication between the central control site and the remote sites, detecting brain response signals from the subject (40) to the task, and having processing means (16) for computing variations in the brain activity for the subjects at each of the selected sites.

Abstract: Electrical activity of the brain is analysed by the application of a repetitive stimulus so as to evoke a steady state response, changes or differences in the steady state response being used as a measure of said electrical activity. The spatial distribution of the activity can be displayed as a topographical representation of the brain, which representation can be updated so as to provide a substantially real-time display. A neuro-psychiatric workstation incorporating such a display can be used for instance for various research purposes.

Abstract: A method and apparatus for determining the level of attention of a subject to a visual stimulus such as a television commercial displayed on a screen (4) so as to provide objective information for designing the advertising presentation. The technique involves reflecting visible red radiation from arrays (16) of LEDs towards the eyes of the subjects (2) as a control signal at a predetermined frequency. The control signal is first applied to the subjects and EEG responses obtained. The control signal is then simultaneously applied with the display of the television commercial and EEG signals are again obtained. An assessment of the subjects interest is then made by determining the diminution in value of the components of the EEG response attributable to the control signal. A pair of illuminated goggles is also disclosed.

Abstract: A method and apparatus for testing the anesthetic depth or consciousness of a subject by directing visible red stimulus signals at the eyes of the subject through closed eyelids at accurately known frequencies. An electroencephalographic (EEG) signal is then obtained and a discriminator (18) is used to accurately detect components at the applied frequencies. An assessment is then made by comparing the magnitude or phase of the components of the EEG signal at the predetermined frequencies with correspondingly obtained EEG signals which have been obtained prior to administration of anesthetic to the subject.