Implantable device for processing neurological signals

• US 7,235,050 B2
• Filed: 08/18/2004
• Issued: 06/26/2007
• Est. Priority Date: 04/11/2002
• Status: Active Grant

• Current Assignee: Alfred E. Mann Foundation For Scientific Research
• Original Assignee: Alfred E. Mann Foundation For Scientific Research
• Inventors: Schulman, Joseph H., Perron, Christian
• Primary Examiner(s): Schaetzle; Kennedy
• Application Number:
  US10/920,544
• Publication Number:
  US 20050085864A1
• Time in Patent Office: 1,042 Days
• Field of Search: 600/300, 600/301, 600/509, 600/544, 600/546, 607/1, 607/2, 607/17, 607/36, 607 39- 41, 607/45, 607/46, 607/50, 607/60, 607/62, 128/902
• US Class Current: 600/300
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0008 Temperature signals
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/1071 measuring angles, e.g. using goniometers A61B5/1123 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37252 Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
• CPC Class Codes: Y10S 128/902 Biological signal amplifier

Abstract

An implantable device comprising a sensing unit, wherein the sensing unit is adapted to rectify biological/neurological signals in the form of sensed electrical signals from body tissue adjacent to the location of the implantable device. The sensing unit of the implantable device comprises at least one amplifier, wherein the supply current to the at least one amplifier is responsive to the magnitude of the sensed electrical signals provided to the at least one amplifier. The implantable device is further capable of integrating the rectified sensed electrical signals and generating output signals, wherein the output signals contain indicia of biopotential parameters of the body tissue.

Claims

1. An implantable device comprising a sensing unit;

wherein the sensing unit is adapted to rectify and integrate sensed electrical signals emanating from tissue adjacent said sensing unit;

wherein the sensing unit comprises at least one amplifier, said at least one amplifier being under the control of a supply current; and

wherein the at least one amplifier has a gain adjustable as a function of the supply current, the supply current being a function of the magnitude of the sensed electrical signals.

2. The implantable device of claim 1, further comprising a controller for receiving the sensed electrical signal and measuring the magnitude of the sensed electrical signal, wherein the controller controls the supply current to the at least one amplifier.

3. The implantable device of claim 2, wherein the supply current to the at least one amplifier is controlled as a function of the magnitude of the sensed electrical signals.

4. The implantable device of claim 3, wherein the supply current to the at least one amplifier is reduced or cutoff when the magnitude of the sensed electrical signals is above a predetermined threshold level.

5. The implantable device of claim 3, wherein the supply current to the at least one amplifier is increased when the magnitude of the sensed electrical signals is below a predetermined threshold level.

6. The implantable device of claim 1, wherein the implantable device comprises an elongate housing have an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm.

7. The implantable device of claim 1, further comprising a transmitter for wirelessly transmitting the integrated rectified sensed electrical signals to receiving circuitry for further processing.

8. The implantable device of claim 7, wherein the integrated sensed electrical signals are averaged over a predefined range between about 1 nanosecond and about 3600 seconds.

9. The implantable device of claim 8, wherein the integrated sensed electrical signals are averaged over an interval of about 10 milliseconds.

10. An implantable device, comprising:

a sensing unit for sensing electrical signals, said sensing unit adapted to rectify and integrate said sensed electrical signals;

a controller for receiving said sensed electrical signals;

at least one amplifier for receiving the sensed electrical signals, wherein the at least one amplifier receives supply current from the controller and wherein the supply current to the at least one amplifier is based on the magnitude of the sensed electrical signals.

11. The implantable device of claim 10, wherein the controller measures the magnitude of the sensed electrical signals and wherein the supply current to the at least one amplifier is reduced or cutoff when the magnitude of the sensed electrical signals is above a predetermined threshold level.

12. The implantable device of claim 10, wherein the controller measures the magnitude of the sensed electrical signals and wherein the supply current to the at least one amplifier is increased when the magnitude of the sensed electrical signals is below a predetermined threshold level.

13. An amplification system adapted for use in an implantable medical device, said system having a system gain, a system input and a system output, the system comprising:

a plurality of amplifiers in switchable series circuit arrangement, between the system input and the system output, each amplifier having a corresponding adjustable gain; and

a controller coupled to each one of the plurality of amplifiers, said controller adapted to switch one or more of the amplifiers into series circuit arrangement, between the system input and the system output, as a function of a sensed parameter, such that the system gain is the product of the corresponding amplifier gain of the amplifiers switched into series circuit arrangement.

14. The amplification system of claim 13, wherein the controller is adapted to adjust the gain of each one of the plurality of amplifiers as a function of the sensed parameter.

15. The amplification system of claim 14, wherein each amplifier operates under the control of a supply current and wherein the controller is adapted to adjust the gain of an amplifier as a function of the sensed parameter, by adjusting the supply current to the respective amplifier.

16. The amplification system of claim 15, wherein the sensed parameter has a measurable value and wherein the controller configures the amplification system to include one or more amplifiers in series circuit arrangement between the system input and system output when the sensed parameter value is below a predetermined threshold value.

17. The amplification system of claim 16, wherein the number of amplifiers configured by the controller to be in series circuit arrangement is a function of the measured sensed parameter value.

18. The amplification system of claim 17, wherein the controller is adapted to remove the supply current from amplifiers not included in the series circuit arrangement.

19. The amplification system of claim 17, wherein the controller is adapted to remove all the amplifiers from the series circuit arrangement and couple the system output to the system input when the sensed parameter value is above a predetermined value.

20. The amplification system of claim 19, wherein the controller is adapted to remove the supply current from all the amplifiers not included in the series circuit arrangement.