Objective pain signal acquisition system and processed signal

• US 6,826,426 B2
• Filed: 10/15/2001
• Issued: 11/30/2004
• Est. Priority Date: 07/06/2000
• Status: Expired due to Fees

• Current Assignee: Algodyne Limited
• Original Assignee: Algodyne Limited
• Inventors: Lewinsky, Reuven, Lange, Daniel H.
• Primary Examiner(s): Jones, Mary Beth
• Assistant Examiner(s): Mallari, Patricia C
• Application Number:
  US09/977,729
• Publication Number:
  US 20020128798A1
• Time in Patent Office: 1,142 Days
• Field of Search: 600/544-545, 600/481, 600/508, 600/509, 600/557, 600/546
• US Class Current: 600/544
• CPC Class Codes: A61B 5/1106 to assess neuromuscular blockade, e.g. to estimate depth of anaesthesia
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/4824 Touch or pain perception evaluation A61B5/4821 takes precedence
• CPC Class Codes: A61B 5/483 by thermal stimulation
• CPC Class Codes: A61B 5/6833 Adhesive patches

Abstract

Methods, apparatuses and systems relating to the objective measurement of the subjective perception of pain in a subject are disclosed. In one aspect, a system for objectively measuring a subjective perception of pain by a subject comprises a plurality of electrodes, including a left channel electrode and a right channel electrode. The plurality of electrodes measures electrical activity at a respective plurality of sites on the subject to generate at least two sets of electrical activity measurements. The system further comprises a processor for processing the at least two sets of electrical activity measurements into at least two normalized signals, and comparing the at least two normalized signals to each other to identify the presence of pain in the subject.

Claims

1. A system for acquiring a signal representative of a subjective perception of pain by a subject comprising:

(a) a sensor array for measuring an electrical signal at a site on the subject;

(b) an amplifier for amplifying the signal;

(c) a band-pass filter connected to the amplifier for at least partially removing components of the signal below about 0.1 Hertz and above about 5 Hertz; and

(d) an analog-to-digital converter for converting the signal into a set of discrete values.

2. The system of claim 1, wherein the sensor array is connected to the band-pass filter, and the analog-to-digital converter is connected to the amplifier.

3. The system of claim 1, wherein the sensor array is connected to the amplifier, and the analog-to-digital converter is connected to the band-pass filter.

4. The system of claim 3, further comprising an optical isolator connecting the sensor array and the amplifier.

5. The system of claim 4, further comprising a memory connected to the analog-to-digital converter for storing the set of discrete values.

6. The system of claim 1, further comprising a memory for storing the set of discrete values.

9. The method of claim 6 further comprising the step of storing the set of discrete values.

7. A method of acquiring an electrical signal representative of a subjective perception of pain by a subject comprising the steps of:

(a) detecting an electrical signal at a site on the subject;

(b) amplifying the signal; and

(c) filtering the signal to at least partially remove components of the signal below about 0.1 Hertz and above about 5 Hertz.

8. The method of claim 7 further comprising a step of converting the signal into a set of discrete values.

10. The method of claim 7 further comprising the step of recording the signal.

11. An electrical signal containing information objectively describing an intensity of a subjective experience of pain in a subject obtained by a process comprising the steps of:

(a) selecting a site on the subject for sensing electrical activity;

(b) detecting electrical activity from the site; and

(c) filtering the electrical activity within a frequency range of about 0.1 Hertz to about 5 Hertz.

12. The electrical signal of claim 11, wherein the site on the subject is the forehead.