Method of displaying and analyzing nonlinear, dynamic brain signals

• US 5,218,530 A
• Filed: 09/11/1989
• Issued: 06/08/1993
• Est. Priority Date: 09/11/1989
• Status: Expired due to Fees

• Current Assignee: George B. Jastrzebski, Lowell R. Wedemeyer
• Original Assignee: George B. Jastrzebski, Lowell R. Wedemeyer
• Inventors: Wedemeyer, Lowell R., Jastrzebski, George B.
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): BODENDORF, ANDREW
• Application Number:
  US07/405,331
• Time in Patent Office: 1,366 Days
• Field of Search: 364/413.05, 364/413.06, 364/413.07, 364/521, 395/119, 395/125, 395/128
• US Class Current: 382/207
• CPC Class Codes: A61B 5/372 Analysis of electroencephalograms
• CPC Class Codes: A61B 5/377 using evoked responses

Abstract

The invention is a method to aid analysis of signals, such as electroencephalograms, pursuant to modern mathematical theories of nonlinear dynamical processes, sometimes referred to as chaotic dynamics or chaos theory. It employs graphic display and visual inspection of relatively less filtered, non-averaged raw test data, including raw data heretofore considered random or asynchronous `noise`. The invention enables reversible decomposition of selected elements of graphic portraits of raw signal data to identify subsets of the depicted raw data which correspond to visually-identified, manually-selected patterns from within the graphic portrait. The identified subsets of raw data can be segregated even though a precise mathematical description of the visually identified pattern is unknown. The invention further comprises a variety of techniques for displaying four or more variables and for enhancing visual discrimination of patterns within computer generated graphic phase space portraits, and conceptions for overlaying symbols onto graphic points representing stimulus and response events concurring with particular signal samples in the phase space portrait. The invention also comprises subsets of pattern-generating signal data identified by the method of the invention and thus made available for further computer or other operations separately from the full data set.

Claims

1. A method of programming and operating a computer to automatically graphically display signal values as graphic drawing entites which form a graphic phase space portrait, and to automatically identify a subset of said signal values corresponding to a manually selected subset of one or more graphic drawing entities which form a visually identified pattern within said graphic phase space portrait, comprising the following steps:

1.1 automatically composing by computer a graphic phase space portrait of signal values collected from a series of two or three signal detectors D1, D2 and D3, said signal values comprising substantially simultaneous signal values D1S1, D2S1, and D3S1 collected at discrete time t1, and substantially simultaneous signal values D1S2, D2S2, and D3S2 collected at discrete time t2, by the following steps;

1.1.1 constructing a graphic drawing point entity P1 having as its drawing coordinates in space at least two of the respective signal values D1S1, D2S1, and D3S1;

1.1.2 constructing a graphic drawing point entity P2 having as its drawing coordinates in space at least two of the respective signal values D1S2, D2S2, and D3S2;

1.1.3 constructing a graphic drawing line entity LI1 connecting and terminating at said two graphic drawing point entities P1 and P2;

1.2 Iterating steps 1.1, 1.1.1, 1.1.2, and 1.1.3 with additional signal values collected substantially simultaneously from at least two of said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . tn;

20. A pattern-containing subset of signal values segregated from a stream of signal values comprising:

a subset of signal values which has been segregated from a stream of signal values by the method of claim 1.

23. A method of operating a computer to automatically graphically display signal data as graphic drawing entities which form a graphic phase space portrait, as in claim 1, and further to automatically identify both (i) a pattern-containing subset of said signal data and (ii) events temporally related to said pattern-containing subset of signal data, from a computer-recorded stream of signal values and temporally related events that correspond to a manually selected subset of one or more graphic drawing entities which form a visually identified pattern within said graphic phase space portrait, comprising the following steps:

22.1 inserting, automatically by computer, one or more flag symbols into a computer-recorded stream of signal values corresponding to the timing of one or more events relative to said signal values;

22.2 performing steps 1.1 through 1.4, inclusive, of claim 1; and

22.3 automatically retrieving by computer, from the computer-recorded stream of signal data and flag symbols, (i) the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified patterns within said graphic phase space portrait, and (ii) any flag symbols previously inserted into said subset of signal values.

25. A method of programming and operating a computer, as in claim 23, further comprising:

24.1 inserting, automatically by computer, one or more flag symbols into a computer-recorded stream of signal values corresponding to the timing of one or more events relative to said signal values;

24.2 Performing steps 23.1 through 23.4, inclusive, of claim 23, and

24.3 automatically retrieving by computer, from the computer-recorded stream of signal data and flag symbols, (i) the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified patterns within said graphic phase space portrait, and (ii) any flag symbols previously inserted into said subset of signal values.

26. A pattern-containing subset of signal values segregated from a stream of signal values comprising:

a subset of signal values which has been segregated from a stream of signal values by the method of claim 23.

2. 3 visually identifying a pattern within said graphic phase space portrait;

1.4 manually commanding the computer to select from within said graphic phase space portrait a subset of one or more graphic drawing entities which form said visually identified pattern; and

1.5 automatically retrieving by computer the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified pattern within said graphic phase space portrait.

4. A method of displaying the time sequence of signal values as a variable dimension in a graphic phase space portrait, as stated in claim 2, including display of periodic increments of a defined time period, further comprising:

3.1 defining a color sequence having a number of distinctive colors corresponding to the number and sequence of periodic increments in a defined time period; and

3.2 serially iterating said color sequence in said line drawing entities in said graphic phase space portrait, one iteration of said color sequence representing one expiration of the defined time period within the displayed time sequence of signal values.

11. A method, as in claim 2, of visually displaying within a graphic phase portrait of a computer-recorded stream of signal values the timing of an event relative to the timing of said signal values, denoted by a graphic drawing event symbol adjacent to the graphic drawing entity which has drawing coordinates corresponding to the signal values recorded substantially simultaneously with said event, comprising:

10.1 inserting automatically by computer a flag symbol into the computer-recorded stream of signal values corresponding to the timing of an event relative to said signal values; and

10.2 drawing a visually distinctive graphic drawing event symbol nearly adjacent to the drawing point entity having drawing coordinates derived from the signal values recorded nearest in time to said flag symbol in said computer-recorded stream of data.

3. A method of graphically displaying the time sequence of signal values as a variable dimension within a graphic phase space portrait of said signal values, comprising the following steps:

2.1 automatically composing by computer a graphic phase space portrait of signal values collected from a series of one or more signal detectors D1, D2, and D3, said signal values comprising substantially simultaneous signal values D1S1, D2S1, and D3S1 collected at discrete time t1, and substantially simultaneous signal values D1S2, D2S2, and D3S2 collected at discrete time t2, by the following steps;

2.1.1 constructing a graphic drawing entity P1 having as its drawing coordinates in space at least two of the respective signal values D1S1, D2S1, and D3S1;

2.1.2 constructing a graphic drawing entity P2 having as its drawing coordinates in space at least two of the respective signal values D1S2, D2S2, and D3S2;

2.2 Iterating steps 2.1, 2.1.1, and 2.1.2 with additional signal values collected substantially simultaneously from at least two of said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . . tn;

2.3 assigning to each of said drawing entities P1, P2, P3, . . . . Pn, in accord with temporal sequence, a visually distinctive color from a pre-determined sequence of colors C1t1, C2t2, C3t3, . . . . Cntn.

5. A method of graphically displaying signal values, comprising the steps of claim 3, and further comprising:

4.1 defining a series of visually-distinctive different color sequences, wherein the number of said different colors is a different prime number in each color sequence;

4.2 iterating said graphic phase space portrait, but substituting a different prime-number color sequence in each iteration.

6. A method of identifying periodicity in signal values, comprising the steps of claim 3 or claim 4, and further comprising:

inspecting each such iteration of said graphic portrait for periodic patterns.

8. A method of visually distinguishing the layers of a composite graphic phase space portrait, composed by the method of claim 6, further comprising:

assigning to each layer of said composite graphic phase space portrait a color visually distinctive from the colors of other layers of said composite portrait.

9. A method of visually distinguishing the layers of a composite phase space portrait, composed by the method of claim 6, further comprising:

assigning to each layer of said composite phase space portrait a drawing entity type visually distinctive from the drawing entity types of other layers of said composite portrait.

10. A method of visually distinguishing the layers of a computer-generated composite graphic phase space portrait, composed by the method of claim 6, further comprising:

assigning to each layer of said composite graphic phase space portrait both a visually distinctive color and a visually distinctive line type, thus enabling each drawing line entity to display up to seven variables consisting of three drawing coordinates, a direction, a color and a line type.

12. A computer-assisted method of visually identifying and manually segregating a pattern-containing subset of signal values from a stream of computer-recorded signal values, which is displayed as graphic drawing entities to form a graphic phase space portrait as in any of claims 2, 3, 4, 6, 7, 8, 9, or 10, further comprising:

11.1 visually identifying a pattern within said graphic phase space portrait;

11.2 manually commanding the computer to select from within said graphic phase space portrait a subset of one or more graphic drawing entities which form said visually identified pattern; and

11.3 automatically retrieving by computer the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified patterns within said graphic phase space portrait.

14. A computer-generated graphic image, as stated in claim 12, further comprising:

13.1 a color sequence having a number of distinctive colors corresponding to a prime number,

13.2 which color sequence is serially iterated for as many multiples of said prime number of drawing line entities as desired.

21. A pattern-containing subset of signal values, from a stream of signal values which has been displayed as graphic drawing entities to form a graphic phase space portrait as in any of claims 2, 3, 4, 6, 7, 8, 9, or 10, where said pattern-containing subset of signal values has been segregated by the method comprising:

20.1 visually identifying a pattern within said graphic phase space portrait;

20.2 manually commanding the computer to select from within said graphic phase space portrait a subset of one or more graphic drawing entities which form said visually identified pattern; and

20.3 automatically retrieving by computer the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified patterns within said graphic phase space portrait.

22. A graphically displayed image, formed by the method of any of claims 2, 3, 4, 6, 7, 8, 9, or 10, comprising:

graphic phase space portrait of signal values.

7. A method of constructing by computer a composite graphic phase space portrait of signal data which has been collected from a set of at least four signal detectors D1, D2, D3, D4, . . . . Dn, comprising substantially simultaneous signal values D1S1, D2S1, D3S1, D4S1, . . . . DnS1 at discrete time t1;

and substantially simultaneous signal values D1S2, D2S2, D3S2, D4S2 . . . . DnS2 at discrete time t2, comprising the following steps;

6.1 automatically composing by computer a first layer LA1 graphic phase space portrait of a subset of said signal values by;

6.1.1 selecting a unique detector subset 1 comprised of two or three detectors Da, Db, and Dc taken from said set of at least four signal detectors D1, D2, D3, D4, . . . . Dn;

6.1.2 constructing a graphic drawing entity P1LA1 having as its drawing coordinates in space the respective signal values DaS1, DbS1, DcS1 . . . . DxS1, collected at time t1 from said unique subset 1 of detectors, Da, Db, and Dc.

6.1.3 constructing a graphic drawing entity P2LA1 having as its drawing coordinates in space the respective signal values DaS2, DbS2, DcS2, . . . . DxS2, collected at time t2 from said unique subset 1 of detectors Da, Db, and Dc;

6.2 iterating the steps of paragraph 6.1 and its subparts with additional signal data for at least one of discrete signal times t3, t4, . . . . tn;

6.3 composing additional layers LA2, LA3, . . . . LAn, of graphic phase space portraits by iterating the steps of paragraph 6.2 and its subparts, but in each additional layer substituting for the signal values of said unique subset 1 of detectors Da, Db, and Dc, the signal values from another unique subset of two or three detectors selected from said set of at least four detectors D1, D2, D3, D4 . . . Dn;

6.4 forming a composite graphic phase space portrait by graphically overlaying the phase space portraits of two or more of said layers LA1, LA2, LA3, . . . . LAn.

13. A computer-generated graphic image comprising:

12.1 a graphic drawing point entity P1 having drawing coordinates corresponding to the values of at least two of signals D1S1, D2S1, and D3S1 which have been collected substantially simultaneously from signal detectors D1, D2 and D3 at discrete time t1;

12.2 a graphic drawing point entity P2 having drawing coordinates corresponding to at least two of signal values D1S2, D2S2, and D3S2 which have been collected substantially simultaneously from signal detectors D1, D2 and D3 at discrete time t2;

12.2.1 a graphic line drawing entity LI1 connecting and terminating at said two drawing point entities P1 and P2;

12.3 Additional drawing point entities P3, P4, . . . . Pn, and drawing line entities LI2, LI3, . . . . LIn, said drawing point and line entities having as their respective drawing coordinates values corresponding respectively to additional signal values D1S3, D2S3, D3S3; and

D1S4, D2S4, D3S4, . . . . DnS4, collected from said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . . tn; and

12.4 each of said line drawing entities LI1, LI2, LI3 . . . . LIn, having a visually distinctive color from a predetermined sequence of colors C1t1, C2t2, C3t3, . . . . Cntn, such that

12.4.1 drawing line LI1 connecting drawing points P1 and P2 has color C1 and thus corresponds to the time interval from t1 to t2;

12.4.2 drawing line LI2 has color C2 corresponding to the time interval between t2 and t3;

. . . . .

12.4.3 drawing line LIn has color Cn.

15. A series of graphic images, comprising iterations of the graphic image of claim 13, but substituting a different prime-number color sequence in each iteration.

17. A composite graphic image, as in claim 15, further comprising a visually distinctive different color assigned to each different layer of said composite graphic image.

18. A composite graphic image, as in claim 15, further comprising a visually distinctive different line type assigned to each different layer of said composite graphic image.

19. A composite graphic computer image, as in claim 15, further comprising:

18.1 visually distinctive different colors assigned to each of one or more of said different layers, and

18.2 visually distinctive different line types assigned to each of one or more of said different layers,

such that each line on a layer can display at least seven variable dimensions, consisting of three spatial coordinates, a direction, a scalar magnitude, a distinctive color, and a distinctive line type.

16. A composite graphic display of signal data which has been collected from a set of at least four signal detectors D1, D2, D3, D4, . . . . Dn, said signal data comprising substantially simultaneous signal values D1S1, D2S1, D3S1, D4S1 . . . . DnS1 at discrete time t1;

and substantially simultaneous signal values D1S2, D2S2, D3S2, D4S2 . . . . DnS2 at discrete time t2, and D1Sn, D2Sn, D3Sn, D4Sn . . . . DnSn at time tn, said composite graphic display comprising the following elements;

15.1 a first layer LA1 graphic phase space portrait of a signal subset 1,

15.1.1 said signal subset 1 comprising the signals from a unique detector subset 1 comprised of two or three detectors Da, Db, and Dc taken from said set of at least four signal detectors D1, D2, D3, D4, . . . . Dn;

15.1.2 a graphic drawing point entity P1LA1 on said first layer LA1 having as its drawing coordinates in space the respective signal values DaS1, DbS1, DcS1, collected at time t1 from said unique subset 1 of detectors, Da, Db, and Dc;

15.1.3 a graphic drawing point entity P2LA1 on said first layer LA1 having as its drawing coordinates in space the respective signal values DaS2, DbS2, DcS2, collected at time t2 from said unique subset 1 of detectors Da, Db, and Dc;

15.1.4 a graphic line drawing entity LI1LA1 on said first layer LA1 between and terminating at said two drawing point entities P1LA1 and P2LA1;

15.2 additional drawing points P3LA1, P4LA1, . . . PnLA1, whose drawing coordinates comprise additional signal values collected from said detector subset 1 for at least one of discrete signal times t3, t4, . . . . tn;

15.3 One or more different layers LA2, LA3, . . . . LAn, of graphic images overlaid with said first layer LA1, wherein the drawing coordinates of the point and line drawing entities on each such different layer correspond to the signal values of a different unique detector subset from said set of detectors D1, D2, D3, D4, . . . . Dn.

24. A method of programming and operating a computer to automatically graphically display signal values as graphic drawing entites which form a graphic phase space portrait, and to automatically identify a subset of said signal values corresponding to a manually selected subset of one or more graphic drawing entities which form a visually identified pattern within said graphic phase space portrait, comprising the following steps:

23.1 automatically composing by computer a graphic phase space portrait of signal values collected from a series of two or three signal detectors D1, D2 and D3, said signal values comprising substantially simultaneous signal values D1S1, D2S1, and D3S1 collected at discrete time t1, and substantially simultaneous signal values D1S2, D2S2, and D3S2 collected at discrete time t2, by the following steps;

23.1.1 constructing a graphic drawing point entity P1 having as its drawing coordinates in space at least two of the respective signal values D1S1, D2S1, and D3S1;

23.1.2 constructing a graphic drawing point entity P2 having as its drawing coordinates in space at least two of the respective signal values D1S2, D2S2, and D3S2;

23.2 Iterating steps 23.1, 23.1.1, and 23.1.2 with additional signal values collected substantially simultaneously from at least two of said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . tn;

23.3 visually identifying a pattern within said graphic phase space portrait;

23.4 manually commanding the computer to select from within said graphic phase space portrait a subset of one or more graphic drawing entities which form said visually identified pattern; and

23.5 automatically retrieving by computer the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified pattern within said graphic phase space portrait.

27. A method of programming and operating a computer to automatically graphically display signal values as graphic drawing entites which form a graphic phase space portrait, and to automatically identify a subset of said signal values corresponding to a manually selected subset of one or more graphic drawing entities which form a visually identified pattern within said graphic phase space portrait, comprising the following steps:

26.1 automatically composing by computer a graphic phase space portrait of signal values collected from a series of one or more signal detectors D1, D2 and D3, said signal values comprising substantially simultaneous signal values D1S1, D2S1, and D3S1 collected at discrete time t1, and substantially simultaneous signal values D1S2, D2S2, and D3S2 collected at discrete time t2, by the following steps;

26.1.1 constructing a graphic drawing point entity P1 having as its drawing coordinates in space at least two of the respective signal values D1S1, D2S1, and D3S1;

26.1.2 constructing a graphic drawing point entity P2 having as its drawing coordinates in space at least two of the respective signal values D1S2, D2S2, and D3S2;

26.2 Iterating steps 26.1.1, 26.1.1, and 26.1.2 with additional signal values collected substantially simultaneously from at least two of said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . . tn;

26.3 visually identifying a pattern within said graphic phase space portrait;

26.4 manually commanding the computer to select from within said graphic phase space portrait a subset of one or more graphic drawing entities which form said visually identified pattern; and

26.5 automatically retrieving by computer the subset of signal values that comprise the drawing coordinates of said selected subset of one or more graphic drawing entities which form said visually identified pattern within said graphic phase space portrait.

28. A method of graphically displaying the time sequence of signal values as a variable dimension within a graphic phase space portrait of said signal values, comprising the following steps:

27.1 automatically composing by computer a graphic phase space portrait of signal values collected from a series of one or more signal detectors D1, D2, and D3, said signal values comprising substantially simultaneous signal values D1S1, D2S1, and D3S1 collected at discrete time t1, and substantially simultaneous signal values D1S2, D2S2, and D3S2 collected at discrete time t2, by the following steps;

27.1.1 constructing a graphic drawing entity P1 having as its drawing coordinates in space at least two of the respective signal values D1S1, and D2S1, and D3S1;

27.1.2 constructing a graphic drawing entity P2 having as its drawing coordinates in space at least two of the respective signal values D1S2, D2S2, and D3S2;

27.2 Iterating steps 27.1, 27.1.1, and 27.1.2 with additional signal values collected substantially simultaneously from at least two of said detectors D1, D2, and D3, at at least one of additional discrete signal times t3, t4, . . . . tn;

27.3 assigning to each of said drawing entities P1, P2, P3, . . . . Pn, in accord with temporal sequence, a visually distinctive color from a pre-determined sequence of colors C1t1, C2t2, C3t3, . . . . Cntn.