| abstract |
In an electroencephalography system and method, 19 brain wave detection electrodes are removably attached to the scalp of the subject being tested. Using a common reference, such as linked earlobes, each of the electrodes is connected to an amplifier, an analog-to-digital converter and a digital computer, which can be a microprocessor. The digital computer is connected to a magnetic disk or a magnetic tape recorder which records the 19 "monopolar" digitized signals. Subsequently a digital computer will construct any desired electrode derivations, such as derivations from coronal bipolar pairs, sagittal bipolar pairs, or compound electrodes representing a whole hemisphere, by an internal program control. These constructed derivations can be displayed in any desired combination, using a conventional inkwriter or electrostatic matrix printer, or subjected to quantitative analyses. Recording time can be substantially reduced by this method, while comparisons between derivations are facilitated since all data, actual or constructed, were recorded simultaneously. |