Activity monitor for pain management efficacy measurement

• US 6,659,968 B1
• Filed: 05/22/2001
• Issued: 12/09/2003
• Est. Priority Date: 06/01/2000
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: McClure, Kelly H.
• Primary Examiner(s): Wolfe, Willis R.
• Application Number:
  US09/862,242
• Time in Patent Office: 931 Days
• Field of Search: 600/300, 600/301, 600/594, 600/595, 607/43, 607/46, 607/19, 607/30, 607/32, 607/60, 607/62, 607/116, 607/117, 435/18, 435/19, 435/20, 705/2, 705/3, 702/19, 702/130, 702/141, 702/190, 702/191
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/4824 Touch or pain perception evaluation A61B5/4821 takes precedence
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: G16H 20/30 relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

An activity monitoring system measures the effectiveness of pain management using using data from motion or activity sensors attached to the patient'"'"'s body to compute measures of exertion level of a patient. Increased levels of exertion are an indication of successful pain management. The patient'"'"'s walking gait smoothness and walking gait stability are also graded as indicators of pain management effectiveness. The motion or activity sensors may be part of a temporary stimulation system used during percutaneous trials, part of a permanent implanted system, or an independent sensor package carried on the patient'"'"'s body. The particular location and axes of the motion or activity sensors may be chosen based on the location of the pain being treated. The effectiveness of a particular pain management stimulation parameter set is based on the statistics accumulated over a period of time, for example one hour.

Claims

1. A method for measuring the effectiveness of pain management, comprising:

attaching an activity monitor to a patient, wherein the activity monitor includes at least one sensor;

collecting sensor data from the sensor;

filtering the sensor data to obtain filtered sensor data, wherein the filter passes signals associated with defined activities;

processing the filtered sensor data to obtain measures of the data associated with the defined activities; and

evaluating the measures to assist in determining the effectiveness of the pain management,

wherein, following processing the filtered sensor data, the method further includes;

accumulating the measures into a first data block; and

tagging the first data block with a stimulation parameter set that is in use when the sensor data was generated to obtain a first tagged data block.

2. The method of claim 1 wherein, following collecting sensor data, the method further includes:

accumulating the sensor data into a second data block;

computing gait metrics for stability and smoothness from the data within the second data block;

determining activity type from the data within the second data block; and

tagging the gait metrics with the activity type to obtain a second tagged data block.

3. The method of claim 2 further including updating a first stimulation parameter set associated with the pain management whose effectiveness is being measured, wherein updating the first stimulation parameter set comprises:

processing the first stimulation parameter set, the first tagged data block, and the second tagged data block to provide a second stimulation parameter set;

comparing the second stimulation parameter set with the first stimulation parameter set to determine if the second stimulation parameter set is more effective than the first stimulation parameter set; and

if so, replacing the first stimulation parameter set with the second stimulation parameter set.

4. The method of claim 3 further including providing an override option wherein a user may elect to keep the first stimulation parameter set rather than replace it with the second stimulation parameter set.

5. A system for measuring the effectiveness of at least one pain management system, the pain management system having a parameter set associated therewith, the system comprising:

a sensor that produces sensor data;

a filter coupled to the sensor that filters the sensor data to produce filtered data, wherein the filter passes signals associated with at least one defined activity;

a processor coupled to the filter that processes the filtered data to produce measures of the at least one defined activity;

a first accumulator that accumulates statistics associated with the measures and forms data blocks therefrom; and

means for tagging the data blocks with the parameter set being used when the sensor data was collected to produce first tagged data blocks.

6. The system of claim 5 further comprising:

a second accumulator adapted to form second data blocks from the filtered data;

means for processing the second data blocks to form gait metrics data blocks;

means for processing the second data blocks to determine an activity type corresponding to the data in the second data blocks; and

means for tagging the gait metrics data blocks with the activity type corresponding to the data in the second data blocks used to produce second tagged data blocks.

7. The system of claim 6 further including:

means for processing the parameter set being used, the first tagged data blocks and the second tagged data blocks in order to evaluate the performance of the parameter set being used; and

means for updating the parameter set being used with an updated parameter set when the performance of the parameter set being used falls below specified criterion.

8. The system of claim 7 wherein the sensor is an accelerometer.

9. The system of claim 8 wherein the means for updating the parameter set includes:

means for defining an updated parameter set;

means for applying the updated parameter set to the pain management system;

means for producing first tagged data blocks and second tagged data blocks using the updated parameter set;

means for computing a score from the first tagged data blocks and the second tagged data blocks corresponding to the updated parameter set;

means for comparing the scores computed for the updated parameter set with a corresponding score computer for the parameter set used prior to the updated parameter set; and

means for selecting the parameter set having the best score as the parameter set to be used by the pain management system.

10. The system of claim 8 wherein the means for updating the parameter set includes:

means for selecting an initial parameter set;

means for applying small perturbations to the initial parameter set, wherein the perturbations define candidate stimulation parameter sets which deviate in several different directions away from the parameter set being used;

means for testing all of the parameter sets and recording scores for each parameter set;

means for selecting the perturbation associated with the initial parameter set that provided the greatest score as a best perturbation;

means for computing a new parameter set that steps in the direction defined by the best perturbation;

means for computing the score for the new parameter set;

means for computing another new parameter set moving in the direction of the best perturbation if the score for the new parameter set exceeds previous scores; and

means for selecting another initial parameter set and beginning the process described above if the score for the new stimulation parameter set is less than previous scores.

11. An Automatic Stimulation Parameter Adjustment (ASPA) system comprising:

a pain management system that reduces pain in a patient, wherein the pain management system exercises a stimulation parameter set;

a sensor adapted to generate sensor data;

a Sensor Data Acquisition (SDA) system including;

means for filtering the sensor data to generate filtered sensor data associated with selected activities; and

means for computing levels of the selected activities from the filtered sensor data;

an Automated Exertion Monitoring (AEM) system including;

means for accumulating a multiplicity of first data blocks of the levels of the selected activities; and

means for tagging the first data blocks with a tag to form tagged data blocks, wherein the tag provides information regarding the stimulation parameter set in use when the sensor data resulting in the data blocks was acquired;

a Walking Gait Monitoring (WGM) system including;

means for accumulating filtered sensor data into second data blocks;

means for computing gait metrics from the second data blocks;

means for determining activity type from the second data blocks; and

means for tagging the gait metrics with the activity type to form tagged gait metrics;

an update system parameters function, wherein the update system parameters function includes means for updating the stimulation parameters based on the present stimulation parameters, the tagged data blocks, and the tagged gait metrics.

12. The system of claim 11 wherein the pain management comprises a Spinal Cord Stimulation (SCS) system, and wherein the SCS system includes an Implantable Pulse Generator (IPG) connected to an implantable electrode array, and wherein the IPG includes means for providing electrical current to the electrode array.

13. The system of claim 11 wherein the sensor includes an accelerometer.

14. The system of claim 11 wherein the means for filtering comprises a bandpass filter with a pass band between about 0.1 Hz and 5 Hz.