APPARATUS AND METHOD FOR OBTAINING EEG DATA

• US 20090312664A1
• Filed: 08/02/2007
• Published: 12/17/2009
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: Imperial Innovations Limited (Imperial College London)
• Original Assignee: Imperial Innovations Limited (Imperial College London)
• Inventors: Yates, David C., Rodriguez Villegas, Esther O.
• Granted Patent: US 8,855,758 B2
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: H03F 2200/375 Circuitry to compensate the offset being present in an amplifier
• CPC Class Codes: H03F 2203/45044 One or more switches are opened or closed to balance the dif amp to reduce the offset of the dif amp
• CPC Class Codes: H03F 3/45995 using switching means

Abstract

An apparatus for obtaining EEG data includes a signal processing component for receiving EEG signals from each of a plurality of electrodes and a data output component. The signal processing component is arranged to convert respective EEG signals in real time to a reduced data set and provide the reduced data set to the data output component.

Claims

1. An apparatus for obtaining EEG data comprising a signal processing component for receiving one or more EEG signals from each of a plurality of electrodes, and a data output component, the signal processing component being arranged to convert respective EEG signals in real time to a reduced data set and provide the reduced data set to the data output component.

2. An apparatus as claimed in claim 1 in which the signal processing component includes at least one analogue signal conversion component to provide a reduced data set.

3. An apparatus as claimed in claim 1 or in which the signal processing component includes a voltage offset removal component arranged to remove voltage offset to reduce the number of bits of the data set.

4. An apparatus as claimed in claim 3 in which the voltage offset removal component comprises an analogue component.

5. An apparatus as claimed in claim 4 in which the voltage offset removal component comprises an analogue chopper amplifier.

6. An apparatus as claimed in claim 5 in which the analogue chopper amplifier comprises sequentially an input chopper switch circuit stage, an amplifier stage and an output chopper switch circuit stage.

7. An apparatus as claimed in claim 6 in which the effective resistance and input capacitance of the input chopper switch circuit stage and the input capacitance of the amplifier stage are designed to form a high pass filter.

8. An apparatus as claimed in claim 67 in which the amplifier stage includes a CMOS component in weak inversion.

9. An apparatus as claimed in claim 1 in which the signal processing component includes a feature extraction component.

10. An apparatus as claimed in claim 9 in which the feature extraction component includes a filter having an impulse response corresponding to an EEG signal profile.

11. An apparatus as claimed in claim 10 in which the impulse response is designed to perform the wavelet transform for a mother wavelet corresponding to an EEG signal profile.

12. An apparatus as claimed in claim 10 in which the feature extraction component is arranged to identify peak filter outputs and identify a corresponding input signal feature for extraction.

13. An apparatus as claimed in claim 9 in which the feature extraction component comprises an analogue component.

14. An apparatus as claimed in claim 9 arranged to extract features from a signal received from a voltage offset removal component as claimed in any of claim 3.

15. An apparatus as claimed in claim 1 in which the signal processing component includes a data compression component.

16. An apparatus as claimed in claim 15 in which the data compression component is arranged to compare first and second respective EEG signals and output a reduced data set representing a correlation between the respective EEG signals.

17. An apparatus as claimed in claim 16 in which the correlation comprises a base signal representation corresponding to one of the first and second respective EEG signals and a generated third signal corresponding to a mathematical relationship between the first and second EEG signals.

18. An apparatus as claimed in claim 17 in which the base signal and the third signal representations are further compressed.

19. An apparatus as claimed in claim 16 in which the data compression component is further arranged to compare at least a third EEG signal.

20. An apparatus as claimed in claim 16 in which EEG signals are grouped for comparison in pre-determined correlation groups.

21. An apparatus as claimed in claim 20 in which the correlation groups are selected based on corresponding electrode placement.

22. An apparatus as claimed in claim 16 in which the data compression component receives a signal from a voltage offset removal component.

23. An apparatus as claimed in claim 16 in which the data compression component receives a signal from a feature extraction component.

24. An apparatus as claimed in claim 1 further comprising an EEG electrode for obtaining an EEG signal for the signal processing component.

25. An apparatus as claimed in claim 24 in which the EEG electrode provides an analogue signal to the signal processing component.

26. An apparatus as claimed in claim 1 in which the data output component comprises at least one transmission component.

27. An apparatus as claimed in claim 26 in which the data output component comprises a wireless transmission.

28. An apparatus as claimed in claim 27 in which the data output component comprises an analogue wireless transmission component.

29. An apparatus as claimed in claim 24 in which the apparatus is mountable on a wearer'"'"'s head.

30. An EEG monitoring system comprising an apparatus as claimed in claim 1 and a base station arranged to receive a data output signal from the data output component.

31. A method of obtaining EEG data comprising receiving EEG signals from each of a plurality of electrodes at a signal processing component, converting the EEG signals in real time to a reduced data set representative of a particular characteristic and providing the reduced data set to a data output component.

32. A method as claimed in claim 31 further comprising transmitting the reduced data set from the data output component to a base station.

33. A method as claimed in claim 31 further comprising identifying an EEG signal representative of seizure or cognitive state onset and providing a seizure or cognitive state onset warning and/or instigating seizure prevention steps.

34. An analogue chopper amplifier comprising, sequentially, an input chopper switch circuit stage, an amplifier stage and an output chopper switch circuit stage, in which the effective resistance and input capacitance of the input chopper switch circuit stage and the input capacitance of the amplifier stage are designed to form a high pass filter.

35. An amplifier as claimed in claim 34 in which the amplifier stage includes a CMOS component in weak inversion.

36. A voltage offset removal component comprising an amplifier as claimed in claim 34.

37. (canceled)