Method and device for interpreting concepts and conceptual thought from brainwave data and for assisting for diagnosis of brainwave disfunction

• US 5,392,788 A
• Filed: 02/03/1993
• Issued: 02/28/1995
• Est. Priority Date: 02/03/1993
• Status: Expired due to Fees

• Current Assignee: Samuel J. Leven
• Original Assignee: William J. Hudspeth
• Inventors: Hudspeth, William J.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/013,026
• Time in Patent Office: 755 Days
• Field of Search: 128/731
• US Class Current: 600/544
• CPC Class Codes: A61B 5/378 Visual stimuli

Abstract

A system for acquisition and decoding of EP and SP signals is provided which comprises a transducer for presenting stimuli to a subject, EEG transducers for recording brainwave signals from the subject, a computer for controlling and synchronizing stimuli presented to the subject and for concurrently recording brainwave signals, and either interpreting signals using a model for conceptual perceptional and emotional thought to correspond EEG signals to thought of the subject or comparing signals to normative EEG signals from a normative population to diagnose and locate the origin of brain dysfunctional underlying perception, conception, and emotion.

Claims

1. A system for acquiring EEG waveforms from a subject and interpreting those waveforms to indicate what the subject is experiencing or thinking, comprising:

means for recording brainwave EEG waveforms from the subject;

means, coupled to said means for recording, for representing a brainwave EEG waveform that has been recorded by the means for recording as a linear combination of a set of basis waveforms, said linear combination consisting of a weighted sum of all members of the set of basis waveforms in which each member of the set of basis waveforms is weighted by a weighting coefficient;

means, coupled to said means for representing, for corresponding thought attributes to members of the set of basis waveforms, a first thought attribute corresponding to a first basis waveform of the set of basis waveforms;

means, coupled to said means for representing, for corresponding each member of a set of thought exemplars for the first thought attribute to a different thought exemplar range of weighting coefficient values for the first basis waveform than any other member of the set of thought exemplars, a first thought exemplar range of weighting coefficients corresponding to a first thought exemplar of the first basis waveform for the first thought attribute;

means, coupled to said means for representing, said means for corresponding thought attributes, and said means for corresponding each member of a set, for determining when the first thought exemplar range includes a weighting coefficient of said linear combination for the first basis waveform;

means, coupled to said means for determining, for generating a thought signal indicating when said weighting coefficient is in the first thought exemplar range;

a device for performing a specified function in response to a thought by the subject;

a controller interface, coupled to said means for generating and to the device, for converting said thought signal into a control signal for controlling the functioning of the device.

2. A system according to claim 1, further comprising:

means, coupled to the means for recording, for presenting stimuli of the stimulus model to said subject.

3. A system according to claim 1, further comprising:

means, coupled to the means for recording, for repetitively presenting a brief first stimuli to the subject;

means, coupled to the means for recording and the means for repetitively presenting, for controlling presentation of the first stimuli to the subject; and

means, coupled to the means for recording and the means for repetitively presenting, for synchronizing presentation of the first stimuli with recording of brainwave EEG waveforms that comprise EP type signals.

4. A system according to claim 1, wherein:

said means for recording comprises an EEG electrode, an analog to digital converter coupled to the EEG electrode, said analog to digital converter functioning by converting a signal provided by the EEG electrode into digital form, a digital CPU coupled to the analog to digital converter, and memory means coupled to the digital CPU.

5. A system according to claim 4, wherein said means for corresponding each member of a set of thought exemplars further comprises:

means for determining correlation values between said brainwave EEG waveform and members of the set of basis waveforms.

6. A system according to claim 4, further comprising an eyeglass frame on which is mounted said means for repetitively presenting.

7. A system according to claim 1, wherein said means for recording comprises EEG electrodes that are connected to an EEG amplifier, an analog to digital converter having an input that is connected to an output of EEG amplifier, and a memory medium that is coupled to said analog to digital converter for storing digital signals provided by the analog to digital converter.

8. A system according to claim 7, further comprising a central processing unit that is coupled to said analog to digital converter and to said memory medium.

9. A system according to claim 8, wherein said means for generating a thought signal comprises an interface that is connected to said central processing unit.

10. A system according to claim 9, further comprising:

means, coupled to the means for recording, for repetitively presenting a brief first stimuli to the subject, said means for repetitively presenting comprising a transducer;

wherein said means for repetitively presenting is coupled to and controlled by said central processing unit.

11. A system according to claim 10, further comprising an eyeglass frame on which is mounted said means for repetitively presenting.

12. A system according to claim 1, wherein said means for recording comprises EEG electrodes that are connected to an EEG amplifier, an analog to digital converter having an input that is connected to an output of said analog to digital converter, and a memory medium, and further comprising:

a central processing unit that is connected to said analog to digital converter;

a display monitor that is connected to and controlled by said central processing unit; and

means, coupled to the central processing unit, for displaying indicia of the thought exemplars of the thought attributes that correspond to members of the set of basis waveforms.

13. A method for acquiring and decoding EEG waveforms from a subject to determine what the subject is thinking, comprising:

recording brainwave EEG waveforms from the subject;

providing a stimulus model representing attributes of stimuli as basis vectors of a vector space and representing exemplars of each attribute as magnitudes for the corresponding basis vectors;

interpreting said EEG waveforms according to a stimulus model in terms of the attributes and the exemplars of the model to determine waveforms corresponding to the attributes and the exemplars.

14. A method for determining attribute waveforms and exemplar coefficients for stimuli of a stimulus set for a subject, comprising the steps of:

modelling the attributes as basis vectors of a vector space and modelling exemplars of an attribute as coefficients for that attribute;

presenting stimuli of the stimulus set to the subject;

recording EEG signals from the subject during the step of presenting stimuli of the stimulus set to the subject, thereby providing recorded EEG signals from the subject;

corresponding each of the recorded EEG signals, to a linear combination of the basis vectors whose coefficients represent exemplars associated with the first stimuli;

determining coefficients and basis vectors representing exemplars and attributes, respectively, which provide a best fit to the recorded EEG signals.

15. A method according to claim 14, wherein the step of determining coefficients and basis vectors representing exemplars and attributes, respectively, which provide a best fit to the recorded EEG signals comprises the step of performing principle components analysis upon the linear combinations of basis vectors and recorded EEG signals from the subject.

16. A system for acquiring EEG waveforms from a subject and interpreting those waveforms to indicate what the subject is thinking, comprising:

first means for recording brainwave EEG waveforms that comprise EP type EEG signals from the subject, comprising an EEG electrode;

second means for repetitively presenting a brief first stimuli to the subject;

third means, coupled to the first means and to the second means, for controlling presentation of the first stimuli to the subject;

fifth means for synchronizing presentation of the first stimuli with recording of said brainwave EEG waveforms by the first means; and

sixth means, coupled to the third means, for presenting second stimuli to said subject during presentation of the first stimuli to the subject by the third means.

17. A system for assisting in diagnosis of brain dysfunction in a subject, comprising:

first means for concurrently recording N brainwave SP waveforms labelled SP_i fir i=1 . . . N from N locations at coordinates x_i,y_i,z_i on the scalp of the subject, comprising EEG transducers;

second means, coupled to the first means, for determining three basis waveforms f₁, f₂, and f₃ which provide the best fit of the function F_i (x_i,y_i,z_i) to the SP_i waveforms, wherein;

space="preserve" listing-type="equation">F.sub.i (x.sub.i,y.sub.i,z.sub.i)=x.sub.i f.sub.1 +y.sub.i f.sub.2 +z.sub.i f.sub.3 +K

where K is a waveform having a constant value;

third means, coupled to the second means, for determining N sets of determined coefficients x1_i, y1_i, z1_i, which each minimize a difference between F_i and SP_i ;

fourth means, coupled to the third means, for storing a jth set of normative values for determined coefficients; and

fifth means, coupled to the third means, for comparing a jth set of the N sets of said determined coefficients for a jth location x_j, y_j, z_j, on the scalp of the subject with the jth set of normative values for determined coefficients, wherein normative values are average values determined from a large population of subjects and said jth set of normative values are determined coefficients at scalp locations of the large population which correspond to said jth location on the scalp of the subject;

means, coupled to the fifth means, for determining when differences between said jth set of said determined coefficients and said jth set of normative values are larger than predetermined differences;

wherein differences between said jth set of said determined coefficients and said jth set of normative values which are larger than predetermined differences indicate brain dysfunction in a region of the brain that is adjacent to the jth location.

18. A method for assisting in diagnosis of brain dysfunction in a subject, comprising:

concurrently recording N brainwave SP waveforms labelled SP_i for i=1 . . . N from N locations at coordinates x_i,y_i,z_i on the scalp of the subject, comprising EEG transducers;

determining three basis waveforms f₁, f₂, and f₃ which provide the best fit of the function F_i (x_i,y_i,z_i) to the SP_i waveforms, wherein;

space="preserve" listing-type="equation">F.sub.i (x.sub.i,y.sub.i,z.sub.i)=x.sub.i f.sub.1 +y.sub.i f.sub.2 +z.sub.i f.sub.3 +K

where K is a waveform having a constant value;

determining N sets of determined coefficients x1_i, y1_i, z1_i, which each minimize a different between F_i and SP_i ; and

storing a jth set of normative values for determined coefficients;

comparing a jth set of the N sets of said determined coefficients for a jth location x_j, y_j, z_j, on the scalp of the subject with the jth set of normative values for determined coefficients, wherein said normative values are average values determined from a large population of subjects and said jth set of normative values are determined coefficients at scalp locations of the large population which correspond to said jth location on the scalp of the subject,

determining when differences between said jth set of said determined coefficients and said jth set of normative values are larger than predetermined differences;

wherein differences between said jth set of said determined coefficients and said jth set of normative values which are larger than predetermined differences indicate brain dysfunction in a region of the brain that is adjacent to the jth location.