Wireless EEG system for effective auditory evoked response

• US 5,755,230 A
• Filed: 09/18/1995
• Issued: 05/26/1998
• Est. Priority Date: 09/18/1995
• Status: Expired due to Term

• Current Assignee: Cleveland Medical Devices Inc.
• Original Assignee: Cleveland Medical Devices Inc.
• Inventors: Buckett, James R., Schmidt, Robert N., Hendrix, Steven P.
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): GILBERT, SAMUEL G
• Application Number:
  US08/529,646
• Time in Patent Office: 981 Days
• Field of Search: 128/731, 128/732, 128/746, 128/640, 128/644, 128/639, 128/903, 128/904
• US Class Current: 600/544
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/38 Acoustic or auditory stimuli

Abstract

A wireless EEG system for effective auditory evoked response, comprising an electrode array which is adapted to be attached to a person and senses voltages produced by the brain electrical activity of the person; transmitter electrically connected to the electrode array such that the transmitter produces a radio frequency signal corresponding to the voltages sensed by the electrode array, encodes the radio frequency signal with error correcting encoding and transmits the radio frequency signal by radio frequency telemetry through a transmitting antenna; the transmitter utilizing carrier frequency shift keyed circuitry to modulate a phase locked loop synthesized carrier frequency and reference frequency shift keyed circuitry to modulate a reference frequency to allow for non-return to zero format of the radio frequency signal obviating the need for Manchester encoding; receiver that receives through a receiving antenna the radio frequency signal produced and transmitted by the transmitter and whereby the receiver decodes the radio frequency signal and produces a data output corresponding to the radio frequency signal received by the receiver; and an operator interface connected to the receiver such that the operator interface receives as input the data output produced by the receiver such that the operator interface records a verbal stimulus given by an individual and provides an auditory stimulus whereby the operator interface displays the data output, such display providing a comparison of the brain electrical activity in response to said stimulus.

Claims

1. A wireless EEG system, comprising:

a) an electrode array having at least two electrodes such that at least one of said electrodes is a reference electrode and at least one of said electrodes is a positive electrode and such that said electrode array is adapted to be attached to a person and senses voltages produced by the brain electrical activity of the person;

b) transmitting means electrically connected to said electrode array such that said transmitting means produces a radio frequency signal corresponding to the voltages sensed by said electrode array, encodes said radio frequency signal with error detecting and correcting encoding and transmits said radio frequency signal by radio frequency telemetry through a transmitting antenna, said transmitting means utilizing carrier frequency shift keyed circuitry to modulate a phase locked loop synthesized carrier frequency and reference frequency shift keyed circuitry to modulate a reference frequency to allow for non-return to zero format of said radio frequency signal;

c) receiving means that receives through a receiving antenna said radio frequency signal produced and transmitted by said transmitting means and wherein said receiving means decodes said radio frequency signal and produces a data output corresponding to said radio frequency signal received by said receiving means; and

d) an operator interface connected to said receiving means such that said operator interface receives as input the data output produced by said receiving means wherein said operator interface displays said data output.

2. The wireless EEG system of claim 1, further comprising, a system controller within said transmitting means such that said system controller conditions said radio frequency signal prior to said transmitting means transmitting said radio frequency signal.

3. The wireless EEG system of claim 2 wherein said system controller outputs a control signal such that said control signal shifts said carrier frequency and said reference frequency by one-half the amount of said frequency shift keyed modulation such that only zero and positive logic levels are needed to modulate said carrier frequency both above and below the nominal nonmodulated carrier frequency.

4. The wireless EEG system of claim 1, further comprising, a microcontroller within said receiving means such that said receiving means is controlled thereby.

5. The wireless EEG system of claim 1 wherein said error correcting encoding is Hamming encoding.

6. The wireless EEG system of claim 1 wherein said electrode array provides a differential input to said transmitting means.

7. The wireless EEG system of claim 1 wherein said electrode array provides a single ended input to said transmitting means.

8. A wireless EEG system for effective auditory evoked response, comprising:

a) an electrode array having at least two electrodes such that at least one of said electrodes is a reference electrode and at least one of said electrodes is a positive electrode and such that said electrode array is adapted to be attached to a person and senses voltages produced by the brain electrical activity of the person;

b) transmitting means electrically connected to said electrode array such that said transmitting means produces a radio frequency signal corresponding to the voltages sensed by said electrode array, encodes said radio frequency signal with error detecting and correcting encoding and transmits said radio frequency signal by radio frequency telemetry through a transmitting antenna, said transmitting means utilizing carrier frequency shift keyed circuitry to modulate a phase locked loop synthesized carrier frequency and reference frequency shift keyed circuitry to modulate a reference frequency to allow for non-return to zero format of said radio frequency signal;

c) receiving means that receives through a receiving antenna said radio frequency signal produced and transmitted by said transmitting means and wherein said receiving means decodes said radio frequency signal and produces a data output corresponding to said radio frequency signal received by said receiving means; and

d) an operator interface connected to said receiving means such that said operator interface receives as input the data output produced by said receiving means and such that said operator interface provides an auditory stimulus wherein said operator interface displays said data output with said display providing a comparison of said brain electrical activity in response to said stimulus and such that said operator interface is programmable.

9. The wireless EEG system for effective auditory evoked response of claim 8, further comprising, a system controller within said transmitting means such that said system controller conditions said radio frequency signal prior to said transmitting means transmitting said radio frequency signal and wherein said system controller outputs a control signal such that said control signal shifts said carrier frequency and said reference frequency by one-half the amount of said frequency shift keyed modulation such that only zero and positive logic levels are needed to modulate said carrier frequency both above and below the nominal nonmodulated carrier frequency.

10. The wireless EEG system for effective auditory evoked response of claim 8, further comprising, a microcontroller within said receiving means such that said receiving means is controlled thereby.

11. The wireless EEG system for effective auditory evoked response of claim 8 wherein said error correcting encoding is Hamming encoding.

12. The wireless EEG system for effective auditory evoked response of claim 8 wherein said electrode array provides a differential input to said transmitting means.

13. The wireless EEG system for effective auditory evoked response of claim 8 wherein said electrode array provides a single ended input to said transmitting means.

14. A wireless EEG system for effective auditory evoked response, comprising:

a) an electrode array having at least two electrodes such that at least one of said electrodes is a reference electrode and at least one of said electrodes is a positive electrode and wherein said electrode array is adapted to be attached to a person and senses voltages produced by the brain electrical activity of the person such that an electrode signal is produced in response thereto;

b) transmitting means electrically connected by wire leads to said electrode array, said transmitting means being electrically powered by battery means therein and having a transmitting antenna, transmitter, system controller and amplifying means also located therein wherein said amplifying means increases the gain of said electrode signal, said transmitter produces a radio frequency signal corresponding to said voltages sensed by said electrode array and said system controller conditions said radio frequency signal and encodes an error detection and correcting encoding thereon, said transmitting means utilizing carrier frequency shift keyed circuitry to modulate a phase locked loop synthesized carrier frequency and reference frequency shift keyed circuitry to modulate a reference frequency to allow for non-return to zero format of said radio frequency signal;

c) receiving means having a receiving antenna that receives said radio frequency signal produced and transmitted by said transmitting means and said receiving means being a superheterodyne type having a microcontroller and wherein said receiving means produces a data output corresponding to the radio frequency signal received by said receiving means; and

d) an operator interface connected to said receiving means such that said operator interface receives as input the data output produced by said receiving means and such that said operator interface records a verbal sound given by an individual and provides an auditory stimulus and wherein said operator interface displays said data output, said display providing a comparison of said brain electrical activity in response to said stimulus and such that said operator interface is programmable.

15. The wireless EEG system for effective auditory evoked response of claim 14 wherein said system controller outputs a control signal such that said control signal shifts said carrier frequency and said reference frequency by one-half the amount of said frequency shift keyed modulation such that only zero and positive logic levels are needed to modulate said carrier frequency both above and below the nominal nonmodulated carrier frequency.

16. The wireless EEG system for effective auditory evoked response of claim 14, further comprising, a circuit board in said transmitting means whereon said transmitting antenna is screen printed.

17. The wireless EEG system for effective auditory evoked response of claim 14, wherein said amplifying means comprises at least one input amplifier.

18. The wireless EEG system for effective auditory evoked response of claim 14 wherein said amplifying means comprises at least one bandpass filter.

19. The wireless EEG system for effective auditory evoked response of claim 14, further comprising a interface cable which connects the receiving means to the operator interface.

20. The wireless EEG system for effective auditory evoked response of claim 14 wherein said operator interface is a personal computer.

21. The wireless EEG system for effective auditory evoked response of claim 14 wherein said transmitter is software controllable and frequency agile over various allowable radio frequency bands.

22. The wireless EEG system of claim 14 wherein said error correcting encoding is Hamming encoding.