Apparatus and method for stimulator on-skin short detection

• US 10,004,445 B2
• Filed: 10/02/2014
• Issued: 06/26/2018
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Neurometrix, Inc.
• Original Assignee: Neurometrix, Inc.
• Inventors: Boettcher, Bonniejean, Herb, Glenn, Kong, Xuan
• Primary Examiner(s): Cohen, Lee S
• Assistant Examiner(s): Cardinal, Erin M
• Application Number:
  US14/505,056
• Publication Number:
  US 20150038873A1
• Time in Patent Office: 1,363 Days
• CPC Class Codes: A61B 2560/0425 Ergonomically shaped housings A61B2560/0418 takes precedence
• CPC Class Codes: A61B 2560/0468 Built-in electrodes
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/388 Nerve conduction study, e.g. detecting action potential of peripheral nerves
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61B 5/6828 Leg

Abstract

The invention relates to apparatus and methods for stimulating living tissues to determine nerve conduction properties using a pair of stimulator probes and a plurality of detection electrodes. The invention overcomes the problem of reporting potentially inaccurate nerve conduction results by detecting a stimulator probe short or shunt condition during nerve conduction tests. Detection of a short or shunt condition between two stimulator probes is accomplished by monitoring the magnitude of the stimulus artifact waveform acquired from the detection electrodes and the voltage difference between the stimulator probes. A test is flagged when magnitude of the stimulus artifact waveform is below a first threshold and voltage difference between the two stimulator probes is below a second threshold. The first and second threshold values are determined based on the known spatial relationship between the stimulator probes and detection electrodes. Feedback is provided to the tester to alert defective test conditions.

Claims

1. A device for measuring sural nerve conduction velocity and amplitude, the device comprising:

a housing;

a stimulation means mounted to the housing for electrically stimulating a human sural nerve;

a biosensor releasably mounted to the housing, the biosensor comprising a plurality of electrodes for detecting a sural nerve response evoked by the stimulation means;

an acquisition means mounted to the housing and electrically connected to the biosensor for electrically acquiring the sural nerve response detected by the biosensor;

a detection means mounted to the housing and electrically connected to the stimulation means and the acquisition means for detecting shorting or shunt of a stimulation current on a skin surface;

a processing means mounted to the housing and electrically connected to the acquisition means for digitizing, processing and storing the acquired sural nerve response;

a calculation means mounted to the housing and electrically connected to the processing means for calculating the conduction velocity and amplitude of the processed sural nerve response; and

a display means mounted to the housing for displaying the sural nerve conduction velocity and amplitude;

wherein the stimulation means and the biosensor are designed to be placed on a patient'"'"'s anatomy, in the vicinity of the human sural nerve, by manipulating the housing;

and further wherein the detection means utilizes a time constant of a decaying rate of a stimulus artifact recorded by the acquisition means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

2. A device according to claim 1 wherein the detection means further utilizes a size of the stimulus artifact recorded by the acquisition means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

3. A device according to claim 1 wherein the stimulation means comprises an anode probe and a cathode probe, and further wherein the detection means further utilizes a voltage difference between the anode probe and the cathode probe of the stimulation means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

4. A device according to claim 1 wherein the stimulation means comprises an anode probe and a cathode probe, and further wherein the detection means utilizes a combination of a voltage difference between the anode probe and the cathode probe of the stimulation means and a size and the decaying rate of the stimulus artifact recorded by the acquisition means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

5. A device according to claim 1 wherein the display means further displays an error message if the detection means determines that there is a shorting or shunt of the stimulation current on the skin surface.

6. A device for measuring sural nerve conduction velocity and amplitude, the device comprising:

a housing;

a stimulation means mounted to the housing for electrically stimulating a human sural nerve;

a biosensor releasably mounted to the housing, the biosensor comprising a plurality of electrodes for detecting a sural nerve response evoked by the stimulation means;

an acquisition means mounted to the housing and electrically connected to the biosensor for electrically acquiring the sural nerve response detected by the biosensor;

a detection means mounted to the housing and electrically connected to the stimulation means and the acquisition means for detecting shorting or shunt of a stimulation current on a skin surface;

a processing means mounted to the housing and electrically connected to the acquisition means for digitizing, processing and storing the acquired sural nerve response;

a calculation means mounted to the housing and electrically connected to the processing means for calculating the conduction velocity and amplitude of the processed sural nerve response; and

a display means mounted to the housing for displaying the sural nerve conduction velocity and amplitude;

wherein the stimulation means and the biosensor are designed to be placed on a patient'"'"'s anatomy, in the vicinity of the human sural nerve, by manipulating the housing;

wherein the stimulation means comprises an anode probe and a cathode probe, and further wherein the detection means utilizes a combination of a voltage difference between the anode probe and the cathode probe of the stimulation means and a size and a decaying rate of a stimulus artifact recorded by the acquisition means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

7. A device according to claim 6 wherein the detection means further utilizes a time constant of the decaying rate of the stimulus artifact recorded by the acquisition means to determine the likelihood of shorting or shunt of the stimulation current on the skin surface.

8. A device according to claim 6 wherein the display means further displays an error message if the detection means determines that there is a shorting or shunt of the stimulation current on the skin surface.