Method and apparatus for three-dimensional mapping of evoked potentials

• US 5,370,126 A
• Filed: 03/23/1993
• Issued: 12/06/1994
• Est. Priority Date: 01/22/1992
• Status: Expired due to Term

• Current Assignee: Neurotech USA, Inc. (Woodbrook Group Holdings, Inc.)
• Original Assignee: Neurotech USA, Inc. (Woodbrook Group Holdings, Inc.)
• Inventors: Clifford, James O. Jr.
• Primary Examiner(s): Lewis, Ralph A.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US08/035,911
• Time in Patent Office: 623 Days
• Field of Search: 128/731, 128/732, 128/733, 128/745, 128/746, 364/413.02, 364/413.05, 364/413.13
• US Class Current: 600/544
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

Coordinating stimuli generation and response signal processing provides for a real-time display of the stimuli response in a three-dimensional coordinate system and allows to select immediately the most appropriate evaluation programs for further processing of sensory information.

Claims

1. An apparatus for sensing and processing stimulated electrical brain signals of a subject under examination comprising

means for generating stimulating signals;

a group of three pairs of sensors adapted to be attached to the head of said subject under examination in planes substantially normal to each other for sensing differential electrical potentials between sensors of each of said pairs of sensors and providing electrical response signals,

each of said pairs of sensors providing an orthogonal

vector element of a triaxial response vector signal;

timing means for initiating said stimulating signals and timing the processing of said response signals;

processing means for receiving said electrical response signals and providing first output information representing sensed signals, and a triaxial response vector signal;

a monitor operatively connected to said processing means for real time display of a plurality of trajectories of successively provided triaxial response vector signals; and

evaluation means including a plurality of analysis means for selectively analyzing said first output information and outputting second output information representing the result of said selectively analyzed first output information.

2. An apparatus as claimed in claim 1, wherein said processing means include means for converting said electrical response signals into digital response data.

3. An apparatus as claimed in claim 2, wherein said processing means further include averaging means for averaging the values of a predetermined number of successive ones of said digital response data.

4. An apparatus as claimed in claim 1 wherein each of said pairs of sensors define an axis, the so defined three axes being substantially normal to each other, and

said electrical response signals constitute axes related electrical response signals.

5. An apparatus as claimed in claim 4, wherein said processing means assemble said response signals to a vector in a three-dimensional space and provide timed trajectory information for the end of said vector.

6. An apparatus as claimed in claim 4, wherein said processing means include a differential amplifier for each one of said pairs of sensors for amplifying said response signal and providing an axis related signal for further use in said processing means.

7. A method for real-time mapping of evoked potentials representing brain activities of a subject under examination comprising the steps of

generating a sequence of stimulating signals for said subject under examination;

gathering a plurality of orthogonally oriented sensory

data signals from said subject under examination;

averaging said sensory data signals over predetermined time periods and providing averaged data signals;

processing said averaged data signals and generating a triaxial vector signal for real-time display in a three-dimensional coordinate system;

displaying and mapping a plurality of trajectories of successively provided triaxial vector signals;

storing said averaged data signals in storage means thereby making said averaged data available for processing at a later time; and

evaluating said stored data signals using a selected one of a plurality of evaluation criteria.

8. A method for real-time mapping of a plurality of evoked response signals representing brain activities of a subject under examination comprising the steps of

generating a sequence of stimulating signals for said subject under examination;

generating timing signals for initiating said stimulating signals;

sensing said plurality of response signals, each of said response signal representing a vector element of a triaxial activity vector;

sampling each one of said response data signals at determined time intervals relative to said sequence of stimulating signals and converting each one of said plurality of sensed data signals to digital data;

averaging said digital data over a predetermined number of said time intervals;

processing said averaged digital data to provide real-time triaxial data vectors;

displaying said real-time triaxial data vectors in a selected triaxial coordinate

system, thereby displaying a time-wise trajectory of said triaxial data vector;

displaying and mapping a plurality of trajectories of successively provided triaxial vector signals;

storing said real-time data thereby making said real-time data available for evaluation at a later time;

applying a fast fourier transform operation to said real-time data for generating frequency domain data;

evaluating said frequency domain data using a selected one of a plurality of evaluation processes; and

providing an output including data on said selected evaluation process.