Apparatus and method for non-invasive blood analyte measurement

• US 5,752,512 A
• Filed: 05/10/1995
• Issued: 05/19/1998
• Est. Priority Date: 05/10/1995
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Gozani, Shai N.
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/435,403
• Time in Patent Office: 1,105 Days
• Field of Search: 128/641, 128/635, 128/630, 128/632, 128/741
• US Class Current: 600/347
• 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 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61B 5/681 Wristwatch-type devices

Abstract

A non-invasive blood analyte concentration monitor. The monitor includes a stimulator applying a stimulus to an endogenous tissue responsive to the stimulus and a detector for detecting a response of an endogenous tissue to the stimulus. Also provided is a correlator which correlates the detected response of the endogenous tissue to an analyte concentration. In one embodiment, the monitored blood analyte is glucose.

Claims

1. An apparatus for determining a concentration of an analyte in a user comprising:

at least two stimulation electrodes adapted for applying an electrical stimulus having a predetermined strength for a predetermined duration to an endogenous tissue;

a detection electrode adapted for detecting an electrical response of an endogenous tissue to said electrical stimulus to provide an electrical response signal; and

a controller adapted for controlling the strength and duration of said electrical stimulus, and for correlating said response signal to an analyte concentration of said user, said controller producing an output which is a quantitative measure of said analyte concentration in response to said electrical response signal.

2. The apparatus recited in claim 1 wherein said analyte is a physiological analyte.

3. The apparatus recited in claim 2 wherein said physiological analyte is glucose.

4. The apparatus recited in claim 1 wherein said analyte is a non-physiological analyte.

5. The apparatus recited in claim 1, wherein said at least two stimulation electrodes are adapted for applying said electrical stimulus to a first endogenous tissue and said detection electrode is adapted for detecting said electrical response of a second endogenous tissue.

6. The apparatus recited in claim 1, wherein said at least two stimulation electrodes are adapted for applying said electrical stimulus to a first endogenous tissue and said detection electrode is adapted for detecting said electrical response from said first endogenous tissue.

7. The apparatus recited in claim 1 wherein said detection electrode comprises a plurality of detection electrodes.

8. The apparatus recited in claim 1 further comprising an occlusion mechanism for obstructing a flow of blood to said stimulated endogenous tissue or to said detected endogenous tissue.

9. The apparatus recited in claim 1 wherein said stimulated endogenous tissue is a nerve and said at least two stimulation electrodes are housed in a cuff adapted for securing to a finger of said user through which said nerve runs.

10. The apparatus recited in claim 9, wherein said cuff is adapted for being pressurized to provide an occlusion mechanism and to cause said at least two stimulation electrodes to contact said finger.

11. The apparatus recited in claim 9 wherein said at least one detection electrode is housed in said cuff.

12. The apparatus recited in claim 9 wherein said at least one detection electrode is housed in a wristband adapted for securing to a wrist of said user through which said nerve runs.

13. A glucose monitor comprising:

a housing having a plurality of user actuable controls thereon;

a controller disposed within said housing and responsive to actuation of said user actuable controls;

a stimulator electrically connected to the controller and adapted to be in communication with a nerve of a user to stimulate said nerve with an electrical impulse in response to a stimulate command from said controller; and

a detector electrically connected to said controller and adapted to be in communication with the nerve of said user to detect an electrical response of said nerve to said electrical impulse in response to a measure command from said controller and for providing said electrical response to said controller, wherein said controller produces an output which is a quantitative measure of said glucose concentration in response to said electrical response.

14. The monitor recited in claim 13, wherein said stimulate command and said measure command are generated by said controller in response to user actuation of a measurement control.

15. The monitor recited in claim 13, wherein said controller is adapted for generating said stimulate command and said measure command when said monitor is calibrated in order to determine a stimulus magnitude evoking a maximum detection sensitivity.

16. The monitor recited in claim 13 wherein said housing is adapted for connection to at least one of:

a modem, a computer, and a memory device.

17. The monitor recited in claim 13 wherein said housing further comprises a display for visually displaying said glucose concentration.

18. The monitor recited in claim 13 wherein said housing further comprises a speaker for audibly indicating said glucose concentration.