Neurostimulator
View Patent ↗Methods and devices for stimulating nerves are disclosed. In one embodiment adapted for stimulating excitable tissue, the invention includes drive circuitry, an acoustic transducer and a pair of electrodes.
1. An implantable neurostimulator comprising:
a first electrode electrically coupled to a first piezoelectric material;
a second electrode electrically coupled to the first piezoelectric material;
a third electrode electrically coupled to a second piezoelectric material;
a fourth electrode electrically coupled to the second piezoelectric material;
where the first piezoelectric material is configured to provide an electrical potential to biological tissue through the first and second electrodes in response to an ultrasound signal;
where the second piezoelectric material is configured to provide an electrical potential to biological tissue through the third and fourth electrodes in response to an ultrasound signal;
where the first and second piezoelectric materials have different resonant frequencies; and
where the first piezoelectric material is a polymer.
2. The implantable neurostimulator of claim 1 , where the polymer is polyvinylidene fluoride (PVDF).
3. The implantable neurostimulator of claim 1 , wherein the first and second piezoelectric materials are physically configured to facilitate insertion of the implantable neurostimulator into biological tissue.
4. The implantable neurostimulator of claim 3 , where the implantable neurostimulator is capable of being inserted into biological tissue using a 16 gauge needle.
5. The implantable neurostimulator of claim 1 , where the first and second piezoelectric materials are mechanically coupled.
6. The implantable neurostimulator of claim 1 , where the first piezoelectric material is made of a different composition than the second piezoelectric material.
7. The implantable neurostimulator of claim 1 , where the first and second piezoelectric materials have resonant frequencies that are sufficiently dissimilar such that when the implantable neurostimulator is subjected to an ultrasound signal having a frequency equal to the resonant frequency of the first piezoelectric material, the second piezoelectric material does not create a significant electrical potential.
8. The implantable neurostimulator of claim 7 , further comprising a third piezoelectric material having a resonant frequency different from the first and second piezoelectric materials.
9. The implantable neurostimulator of claim 1 , further comprising a third piezoelectric material electrically connected in series with the first piezoelectric material, where the third piezoelectric material has a resonant frequency having substantially the same as the resonant frequency as the first piezoelectric material.
10. The implantable neurostimulator of claim 9 , further comprising a fourth piezoelectric material electrically connected in series with the second piezoelectric material, where the fourth piezoelectric material has a resonant frequency substantially the same as the resonant frequency of the second piezoelectric material.
11. The implantable neurostimulator of claim 1 , where the second piezoelectric material is a ceramic.
12. The implantable neurostimulator of claim 11 , where the ceramic is lead zirconate titanate (PZT).
13. The implantable neurostimulator of claim 11 , where the ceramic is lithium nobate.
14. The implantable neurostimulator of claim 11 , where the ceramic is lead metaniobate.
15. The implantable neurostimulator of claim 11 , where the ceramic is lead titanate.
16. The implantable neurostimulator of claim 1 , where the second piezoelectric material is a crystal.
17. The implantable neurostimulator of claim 16 , where the crystal is quartz.
18. The implantable neurostimulator of claim 16 , where the crystal is tourmaline.