SKIN IMPEDANCE MATCHING SYSTEM AND METHOD FOR SKIN/ELECTRODE INTERFACE

• US 20080275316A1
• Filed: 05/02/2008
• Published: 11/06/2008
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Reproductive Research Technologies, LP
• Original Assignee: Reproductive Research Technologies, LP
• Inventors: McCRARY, Jack N., FINK, Rainer J.
• Granted Patent: US 8,444,559 B2
• Time in Patent Office: Days
• US Class Current: 600/306
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/304 Switching circuits
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment

Abstract

The present invention relates to a system for measuring the input impedance of a skin/electrode interface and selectively modifying the input impedance of the monitoring circuit to match the measured input impedance. More particularly, a simplified method for correcting for input impedance mismatch between electronic monitoring circuitry and the skin/electrode interface. In accordance with one embodiment of the invention, an input impedance measuring circuit will interface with a microprocessor and a reconfigurable switch network to select the input impedance of the electronic monitoring circuitry, thus eliminating the impedance sensitivity of EMG or EKG instruments.

Claims

1. A system for matching skin impedance of a patient, comprising:

a first module adapted to determine the skin impedance;

a resistor network adapted to match the skin impedance using one or more resistors;

a processor adapted to configure the resistor network based at least in part on input received from the first module; and

a second module adapted to sense signals through electrodes coupled to the skin in conjunction with the resistor network.

2. The system as set forth in claim 1, wherein the first and second modules use identical electrodes.

3. The system as set forth in claim 1, wherein the first module comprises a sensing resistor, an amplifier, and an analog to digital converter.

4. The system as set forth in claim 1, further comprising a pair of switches controlled by the processor for switching between the first and second modules.

5. The system as set forth in claim 1, wherein the second module provides the signals to an external medical device.

6. The system as set forth in claim 5, wherein the signals are calibrated by the second module using the resistor network.

7. The system as set forth in claim 1, wherein the resistor network is digitally configured by the processor through a plurality of control signals.

8. A method for matching skin impedance of a patient, comprising:

switching to a matching mode;

determining the skin impedance using a test voltage;

switching a resistor network to match the skin impedance;

switching to a sensing mode;

measuring voltage inputs from the skin; and

calibrating the inputs using the resistor network.

9. The method as set forth in claim 8, wherein the determining and measuring steps are performed using identical electrodes.

10. The method as set forth in claim 8, further comprising the step of providing the calibrated inputs to an external medical device.

11. The method as set forth in claim 10, wherein the switching and determining steps are performed by a processor integral to a mechanism interposed between the patient and the medical device.

12. The method as set forth in claim 11, wherein the resistor network is digitally configured by the processor through a plurality of control signals.