Aperiodic analysis system, as for the electroencephalogram

• US 4,215,697 A
• Filed: 12/26/1978
• Issued: 08/05/1980
• Est. Priority Date: 12/26/1978
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Demetrescu, Mihai C.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/973,423
• Time in Patent Office: 588 Days
• Field of Search: 128/731, 128/712, 128/710, 128/699
• US Class Current: 600/544
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16

Abstract

An aperiodic signal is preliminarily processed by an active network to provide three relatively separate components that include: slow waves (waveform cycles or fragments of equivalent frequency from 1 to 8 hertz), fast waves (waveform cycles or fragments of equivalent frequency from 8 to 30 hertz), and a signal component which may contain spikes (fast, large, sharp single waves). The component signals or waves are applied to individual detector circuits which indicate amplitude and period (or equivalent frequency) information for detected waves and the amplitude for recognized spikes, as well as the time of their occurrence. Detected waves (including spikes) produce representative trigger signals which are applied through a multiplexer to a storage device, specifically a cathode ray tube on which the waves and spikes are representatively displayed and stored to complete a static picture which indicates an internal of the waveform. As disclosed, a representation or picture is generated on the storage tube by controlling the horizontal and vertical amplifiers and appropriately blanking the beam to develop a composite display that summarizes many seconds of the aperiodic signal. The display is a three-dimensional representation with each wave represented by a line that extends in one dimension to indicate amplitude. The position of the line in another dimension indicates the period or equivalent frequency, and its position in the third dimension indicates the time of occurrence of the wave.

Claims

1. A system for analyzing an interval of an aperiodic waveform, manifest as an electrical signal, comprising:

means for detecting predetermined individual waves in said electrical signal to provide individual wave signals representative of the time of occurrence, the period and the amplitude of a detected wave;

a storage means for containing a three-dimensional static image; and

means connected to receive said individual wave signals for scaling said wave signals into said three-dimensional image to depict waves as linear symbols positioned in one dimension with reference to period and in another dimension with reference to time of occurrence and scaled in the third dimension with perspective adjustment to indicate amplitude.

2. A system according to claim 1 further including means for sensing an interval of EEG and means for supplying said EEG to said means for detecting.

3. A display system according to claim 1 wherein said display means include an electronic module to process according to perspective representation each of said symbols representative of each incoming wave, and further include a storage oscilloscope on the screen of which successively incoming linear symbols are stored and displayed.

4. A display system according to claim 1 where said display means include an electronic module to process according to perspective representation the duration, amplitude and time of occurrence to each incoming wave to result in a virtual symbol, and further including plotter means to actually plot said symbols on a writing medium such as to progressively construct said static three-dimensional image.

5. A system according to claim 1 wherein said storage means comprises a cathode ray storage tube for developing a static image and said means for scaling actuates said tube on the occurrence of said waves to provide representative displays.

6. A system according to claim 1 further including a hard-copy unit for providing a sheet of paper depicting said static image.

7. A system according to claim 1 wherein said means for detecting includes means for separating said electrical signal into wave components and further includes means for measuring the period of said wave components.

8. A system according to claim 7 wherein said means for detecting further includes a wave detector for at least one of said wave components to detect the occurrence of waves with an amplitude below a predetermined minimum amplitude and discriminate against said waves.

9. A system according to claim 8 wherein said wave detector further includes means to discriminate against wave components outside predetermined period limits.

10. A system according to claim 7 wherein said means for detecting further includes means for detecting signal spikes in one of said wave components.

11. A system according to claim 7 further including a plurality of detectors for receiving said wave components, to detect within predetermined limits the amplitude and period of said wave components.

12. A system according to claim 11 further including a multiplexer for connecting said plurality of detectors to said storage means.

13. A system according to claim 1 wherein said storage means comprises a display generator and said system further includes means for indicating calibration marks on said display.