Programmable signal analysis device for detecting neurological signals in an implantable device

• US 20030195578A1
• Filed: 04/11/2002
• Published: 10/16/2003
• 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., Mandell, Lee J., Perron, Christian Y.
• Granted Patent: US 6,990,372 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient

Abstract

A programmable signal analysis device for detecting and counting neurological and muscular events in living tissue that incorporates one or more signal threshold levels to identify an event, a counter to count events, and a timer to determine event frequency as events per unit time. The threshold levels and counter/timer operating modes/parameters are digitally programmable to identify and count events, i.e., electrical signals having defined parameters. Such a circuit is of particular use in a microstimulator/sensor which is capable of being injected into living tissue at the site of interest. The microstimulator/sensor is used to stimulate a neural pathway or muscle and/or to block a neural pathway to alleviate pain or block stimulation of a muscle.

Claims

1. A signal analysis device for use within an implantable device, wherein said implantable device is configured at least in part for sensing a biological signal within a patient'"'"'s body and said implantable device is contained within a sealed elongate housing having an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm, said signal analysis device comprising:

sensing circuitry for receiving a biological signal within said implantable device and generating a sensed voltage output in response thereto;

event detection circuitry for detecting an attribute of said sensed output according to one or more designated criteria and designating said detected attribute as an event;

an event counter configured for accumulating detected events;

a clocked counter for accumulating clock pulses; and

event analysis circuitry for determining a processed value corresponding to said detected events and said accumulated clock pulses.

2. The signal analysis device of claim 1 wherein said event analysis circuitry is configurable for operation in a plurality of modes of operation.

3. The signal analysis device of claim 2 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining the rate at which said detected events occur.

4. The signal analysis device of claim 2 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining the number of said detected events which occur within a designated time period.

5. The signal analysis device of claim 2 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining a numerical value corresponding to time elapsed between a designated start time and the first of said detected events which occur.

6. The signal analysis device of claim 2 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining a numerical value corresponding to time elapsed for a prescribed number of said detected events.

7. The signal analysis device of claim 1 wherein said event detection and said event analysis circuitry comprise a mode of operation for determining a numerical value corresponding to time elapsed between a start time of a detected event and an end time of said designated event.

8. The signal analysis device of claim 1 wherein said event detection circuitry is alternatively configurable for determining whether an event occurred according to one or according to two or more programmable criteria.

9. The signal analysis device of claim 8 wherein said programmable criteria include at least first and second threshold levels and is further alternatively configurable to determine an event when:

said sensed voltage output increases above said first threshold level and then decreases below said first threshold level;

or

said sensed voltage output increases above said first threshold level and then decreases below said first threshold level without exceeding said second threshold level.

10. The signal analysis device of claim 9 wherein said signal analysis device additionally comprises:

an average peak detector for determining an average peak value of voltage peaks of said sensed voltage output; and

wherein

said first and second threshold levels are effectively adjusted according to changes in said average peak value.

11. The signal analysis device of claim 1 wherein said event detection circuitry includes exclusion circuitry for excluding detected events according to programmable criteria.

12. The signal analysis device of claim 1 additionally comprising:

a peak detector for determining peaks of said sensed voltage output; and

wherein

said event detection circuitry designates said peaks as events.

13. The signal analysis device of claim 1 wherein said programmable criteria includes at least first and second threshold levels and wherein said signal analysis device additionally comprises:

a peak detector for determining peaks of said sensed voltage output; and

wherein

said event detection circuitry designates said peaks as events when said peaks correspond to voltages that are greater than said first threshold level and less than said second threshold level.

14. The signal analysis device of claim 1 wherein said event detection circuitry comprises:

first and second digital to analog converters for receiving digital values corresponding to first and second programmable threshold levels and generating first and second analog threshold levels in response thereto;

first and second comparators for comparing said first and second analog threshold levels to said sensed voltage output; and

programmable criteria logic for receiving outputs from said first and second comparators and determining events according to programmable criteria.

15. The signal analysis device of claim 1 wherein said event detection circuitry comprises:

an analog to digital converter for receiving said sensed voltage output and periodically converting said sensed voltage output value to a digital sensed voltage value; and

programmable criteria logic for receiving said digital sensed voltage value and determining events according to programmable criteria related to said digital sensed voltage value.

16. The signal analysis device of claim 15 wherein said programmable criteria logic comprises a digital signal processor.

17. The signal analysis device of claim 1 wherein said event detection circuitry comprises a digital signal processor for receiving said sensed voltage output, periodically converting said sensed voltage output to a digital sensed voltage value, and determining events according to programmable criteria related to said digital sensed voltage value.

18. The signal analysis device of claim 17 wherein said digital signal processor additionally includes said event analysis circuitry.

19. A signal analysis device for use within an implantable device, wherein said implantable device is configured at least in part for sensing a biological signal within a patient'"'"'s body, said signal analysis device comprising:

sensing circuitry for receiving a biological signal within said implantable device and generating a sensed voltage output in response thereto;

event detection circuitry that is alternatively configurable to determine whether an event occurred according to one or according to two or more programmable criteria for detecting an attribute of said sensed voltage output and designating said detected attribute as an event;

an event counter configured for accumulating detected events;

a clocked counter for accumulating clock pulses; and

event analysis circuitry configurable for operation in a plurality of modes of operation for determining a processed value corresponding to said detected events and said accumulated clock pulses.

20. The signal analysis device of claim 19 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining the rate at which said detected events occur.

21. The signal analysis device of claim 19 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining the number of said detected events which occur within a designated time period.

22. The signal analysis device of claim 19 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining a numerical value corresponding to time elapsed between a designated start time and the first of said detected events which occur.

23. The signal analysis device of claim 19 wherein at least one of said modes of operation of said event analysis circuitry comprises a mode for determining a numerical value corresponding to time elapsed for a prescribed number of said detected events.

24. The signal analysis device of claim 19 wherein said event detection and said event analysis circuitry comprise a mode of operation for determining a numerical value corresponding to time elapsed between a start time of a detected event and an end time of said designated event.

25. The signal analysis device of claim 19 wherein said programmable criteria include at least first and second threshold levels and is further alternatively configurable to determine an event when:

said sensed voltage output increases above said first threshold level and then decreases below said first threshold level;

or

said sensed voltage output increases above said first threshold level and then decreases below said first threshold level without exceeding said second threshold level.

26. The signal analysis device of claim 25 wherein said signal analysis device additionally comprises:

an average peak detector for determining an average peak value of voltage peaks of said sensed voltage output; and

wherein

said first and second threshold levels are effectively adjusted according to changes in said average peak value.

27. The signal analysis device of claim 19 wherein said event detection circuitry includes exclusion circuitry for excluding detected events according to programmable criteria.

28. The signal analysis device of claim 19 additionally comprising:

a peak detector for determining peaks of said sensed voltage output; and

wherein

said event detection circuitry designates said peaks as events.

29. The signal analysis device of claim 19 wherein said programmable criteria includes at least first and second threshold levels and wherein said signal analysis device additionally comprises:

a peak detector for determining peaks of said sensed voltage output; and

wherein

said event detection circuitry designates said peaks as events when said peaks correspond to voltages that are greater than said first threshold level and less than said second threshold level.

30. The signal analysis device of claim 19 wherein said event detection circuitry comprises:

first and second digital to analog converters for receiving digital values corresponding to first and second programmable threshold levels and generating first and second analog threshold levels in response thereto;

first and second comparators for comparing said first and second analog threshold levels to said sensed voltage output; and

programmable criteria logic for receiving outputs from said first and second comparators and determining events according to programmable criteria.

31. The signal analysis device of claim 19 wherein said event detection circuitry comprises:

an analog to digital converter for receiving said sensed voltage output and periodically converting said sensed voltage output value to a digital sensed voltage value; and

programmable criteria logic for receiving said digital sensed voltage value and determining events according to programmable criteria.

32. The signal analysis device of claim 19 wherein said programmable criteria logic comprises a digital signal processor.

33. The signal analysis device of claim 19 wherein said event detection circuitry comprises a digital signal processor for receiving said sensed voltage output, periodically converting said analog sensed voltage output to a digital sensed voltage value, and determining events according to programmable criteria related to said digital sensed voltage value.

34. The signal analysis device of claim 33 wherein said digital signal processor additionally includes said event analysis circuitry.

35. A method for processing a biological signal from a patient'"'"'s body to determine a body parameter, said method comprising the steps of:

sensing a neurological signal from within the patient'"'"'s body to generate a sensed voltage output in response thereto;

detecting an attribute of said sensed voltage output and designating said detected attribute as an event wherein said detecting is alternatively configurable to determine whether said event occurred according to one or according to two or more programmable criteria;

accumulating said detected events;

accumulated clock pulses; and

determining a processed value corresponding to said detected events and said accumulated clock pulses, wherein said determining step is configurable for operation in a plurality of modes of operation.