Neural Signal Processing

• US 20090118597A1
• Filed: 11/05/2008
• Published: 05/07/2009
• Est. Priority Date: 11/05/2007
• Status: Abandoned Application

• Current Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Original Assignee: Data Sciences U K Limited (International Business Machines Corporation)
• Inventors: Brockway, Marina V., Brockway, Brian P., Mills, Perry A.
• Application Number:
  US12/265,541
• Publication Number:
  US 20090118597A1
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system

Abstract

A method of monitoring neural signal activity with an implantable monitoring device implanted in a living subject includes amplifying a neural signal having a signal bandwidth of at least 1000 Hz. The method also includes processing the amplified neural signal to produce a reduced-bandwidth derivative neural signal representative of gross activity of the neural signal, and wirelessly transmitting the derivative neural signal from the implantable monitoring device for receipt by a receiver external of the living subject.

Claims

1. A method of monitoring neural signal activity with an implantable monitoring device implanted in a living subject, comprising:

amplifying a neural signal having a signal bandwidth of at least 1000 Hz;

processing the amplified neural signal to produce a reduced-bandwidth derivative neural signal representative of gross activity of the neural signal; and

wirelessly transmitting the derivative neural signal from the implantable monitoring device for receipt by a receiver external of the living subject.

2. The method of claim 1, wherein the derivative neural signal has a signal bandwidth of less than about 250 Hz.

3. The method of claim 1, further comprising sampling the amplified neural signal and wirelessly transmitting the sampled signal for receipt by a receiver external of the living subject, wherein the sampling preserves full bandwidth of the amplified neural signal.

4. The method of claim 3, wherein transmission of the derivative neural signal and the full-bandwidth sampled signal occurs simultaneously.

5. The method of claim 1, wherein processing the amplified neural signal includes rectifying and integrating the amplified neural signal.

6. The method of claim 1, wherein processing the amplified neural signal includes detecting successive local extrema of the amplified neural signal.

7. The method of claim 1, further comprising determining and subtracting an offset from the derivative neural signal, where the offset represents a contribution of noise to the derivative neural signal.

8. The method of claim 1, further comprising using the derivative neural signal to modulate a periodic waveform.

9. The method of claim 1, wherein the neural signal is accessed using electrodes in contact with a renal nerve of the living subject.

10. The method of claim 1, further comprising assessing the derivative neural signal to predict occurrence of a future physiological change for the living subject.

11. An implantable monitoring device, comprising:

an acquisition circuit configured to amplify a neural signal having a signal bandwidth of at least 1000 Hz;

a processing circuit configured to process the amplified neural signal to produce a derivative neural signal representative of gross activity of the neural signal; and

a transmitter circuit configured to wirelessly transmit the derivative neural signal from the implantable monitoring device for receipt by a receiver external of the living subject.

12. The implantable monitoring device of claim 11, further comprising a control circuit that when activated causes the transmitter circuit to wirelessly transmit the amplified neural signal for receipt by a receiver external of the living subject.

13. The implantable monitoring device of claim 12, further comprising a second transmitter circuit, and wherein transmission of the derivative neural signal and the amplified neural signal occurs simultaneously over the transmitter circuit and second transmitter circuit, respectively.

14. The implantable monitoring device of claim 11, wherein the processing circuit is configured to rectify and integrate the amplified neural signal.

15. The implantable monitoring device of claim 11, wherein the processing circuit is configured to detect successive local extrema of the amplified neural signal.

16. The implantable monitoring device of claim 11, wherein the processing circuit is configured to determine and subtract an offset from the derivative neural signal, where the offset represents a contribution of noise to the derivative neural signal.

17. The implantable monitoring device of claim 11, further comprising a modulator to modulate a periodic waveform using the derivative neural signal.

18. The implantable monitoring device of claim 11, wherein the neural signal is accessed using electrodes in contact with a renal nerve of the living subject.

19. The implantable monitoring device of claim 11, wherein the acquisition circuit and the processing circuit are housed in a first enclosure, the transmitter circuit is housed in a second enclosure, and wherein the derivative neural signal is passed from an output of the first enclosure to an input of the second enclosure.

20. The implantable monitoring device of claim 19, wherein the second enclosure houses circuitry for monitoring one or more vital signs of an implanted subject, and wherein the input of the second enclosure is a biopotential input.

21. A method of monitoring neural signal activity with an implantable monitoring device implanted in a living subject, comprising:

sampling a neural signal, having a signal bandwidth of at least 1000 Hz, at a predetermined sampling frequency less than a Nyquist frequency for the neural signal to produce an undersampled neural signal from which gross activity of the neural signal can be derived; and

wirelessly transmitting the undersampled neural signal from the implantable monitoring device for receipt by a receiver external of the living subject.