Ocular micro tremor (OMT) sensor, system and method
An eye sensor, system and method for measuring fixational eye movements of an individual's eyeball (e.g., ocular microtremors and microsaccades) to provide a variable voltage biosignal for measuring the individual's brain stem activity. The eye sensor comprises a sensor mounted on the individual's closed or opened eyelid so as to be deflected by the fixational eye movements of the eyeball. A shielded flexible ribbon assembly supplies the biosignal generated by the sensor to an amplifier located on the individual's skin where the biosignal is amplified. The amplifier is interconnected with a signal processor and a display by which graphical and numerical representations of the biosignal are made accessible to an anesthesiologist, intensivist or clinician. A method for analyzing the biosignal to determine the brainstem activity of a patient.
1. An apparatus comprising:
a sensor comprising a piezoelectric element; and
a flexible ribbon assembly comprising a conductive trace, wherein the conductive trace is coupled to the piezoelectric element;
wherein the sensor is configured to conform to a shape of an eye register micro-movements of an eyeball having an amplitude in an inclusive range of 40 micrometers to 500 nanometers.
2. The apparatus of claim 1 , wherein the sensor further comprises a conductive shield.
3. The apparatus of claim 1 , wherein the sensor further comprises a conductive shield and an insulator, wherein the insulator insulates the conductive trace from the conductive shield.
4. The apparatus of claim 1 , wherein the sensor further comprises a conductive shield and an insulator, wherein the insulator insulates the piezoelectric element from the conductive shield.
5. The apparatus of claim 1 , wherein the piezoelectric element is 20 microns to 150 microns thick.
6. The apparatus of claim 1 , wherein the piezoelectric element comprises Polyvinylidene fluoride.
7. The apparatus of claim 1 , wherein the sensor further comprises an adhesive configured to attach to an eyelid.
8. The apparatus of claim 2 , wherein the conductive shield comprises gold.
9. The apparatus of claim 1 , wherein the sensor is further configured to register micro-movements of an eyeball having a frequency of 84 Hz.
10. The apparatus of claim 2 , wherein the conductive shield is in electrical communication with the conductive trace.
11. An apparatus comprising:
a sensor comprising:
a sensing element comprising:
a piezoelectric element; and
an electrically conductive surface electrically coupled with the piezoelectric element; and
an amplifier comprising a receptacle electrically coupled with the electrically conductive surface;
wherein the sensor is configured to conform to a shape of an eye of a patient and to register micro-movements of an eyeball having an amplitude in an inclusive range of 40 micrometers to 500 nanometers.
12. The apparatus of claim 11 , wherein the sensor further comprises a conductive shield.
13. The apparatus of claim 11 , wherein the sensor further comprises a conductive shield and an insulator, wherein the insulator insulates the piezoelectric element from the conductive shield.
14. The apparatus of claim 11 , wherein the piezoelectric element is 20 microns to 150 microns thick.
15. The apparatus of claim 11 , wherein the piezoelectric element comprises Polyvinylidene fluoride.
16. The apparatus of claim 11 , wherein the sensor further comprises an adhesive configured to attach to an eyelid.
17. The apparatus of claim 12 , wherein the conductive shield comprises gold.
18. The apparatus of claim 11 , wherein the sensor is further configured to register micro-movements of an eyeball having a frequency of 84 Hz.
19. The apparatus of claim 12 , wherein the conductive shield is in electrical communication with the electrically conductive surface.
20. An apparatus comprising:
a sensor comprising a piezoelectric element; and
a conductor, wherein the conductor is electrically coupled to the piezoelectric element;
wherein the sensor is configured to conform to a shape of an eye; and the sensor is configured to register micro-movements of an eyeball having an amplitude in an inclusive range of 40 micrometers to 500 nanometers.
21. The apparatus of claim 20 , wherein the sensor further comprises a conductive shield.
22. The apparatus of claim 20 , wherein the sensor further comprises a conductive shield and an insulator, wherein the insulator insulates the piezoelectric element from the conductive shield.
23. The apparatus of claim 20 , wherein the piezoelectric element is 20 microns to 150 microns thick.
24. The apparatus of claim 20 , wherein the piezoelectric element comprises Polyvinylidene fluoride.
25. The apparatus of claim 20 , wherein the sensor further comprises an adhesive configured to attach to an eyelid.
26. The apparatus of claim 21 , wherein the conductive shield comprises gold.
27. The apparatus of claim 20 , wherein the sensor is further configured to register micro-movements of an eyeball having a frequency of 84 Hz.
28. The apparatus of claim 21 , wherein the conductive shield is in electrical communication with the conductor.
29. The apparatus of claim 1 , wherein the conductive trace is in direct contact with the piezoelectric element.
30. The apparatus of claim 11 , wherein the electrically conductive surface is in direct contact with the piezoelectric element.
31. The apparatus of claim 21 , wherein the conductor is in direct contact with the piezoelectric element.