At least partially implantable system for rehabilitation of a hearing disorder

• US 6,575,894 B2
• Filed: 04/13/2001
• Issued: 06/10/2003
• Est. Priority Date: 04/13/2000
• Status: Expired due to Fees

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Waldmann, Bernd, Leysieffer, Hans
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/833,704
• Publication Number:
  US 20020029070A1
• Time in Patent Office: 788 Days
• Field of Search: 607/55-57, 607/137, 600/25
• US Class Current: 600/25
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/36036 of the outer, middle or inner ear
• CPC Class Codes: A61N 1/36038 Cochlear stimulation

Abstract

An at least partially implantable system for rehabilitation of a hearing disorder with at least one sensor for picking up an acoustic signal and converting the acoustic signal into corresponding electrical signals, an electronic signal processing unit for audio signal processing and amplification, an electrical power supply unit which supplies energy to individual components of the system, and an output-side electromechanical transducer arrangement which consists of at least two independent and spatially separate transducers for stimulation of the inner ear. In conformity with the invention, the output-side electromechanical transducers are designed for stimulation of the fluid-filled inner ear spaces of the damaged inner ear and the signal processing unit comprises driving signal processing electronics which electrically controls each of the transducers such that a traveling wave configuration is formed on the basilar membrane of the damaged inner ear. The traveling wave configuration approximates the formation of a traveling wave of a healthy, undamaged inner ear.

Claims

1. An at least partially implantable system for rehabilitation of a hearing disorder which comprises:

at least one acoustic sensor for picking up an acoustic signal and converting the acoustic signal into corresponding electrical signals,

an electronic signal processing unit for audio signal processing and amplification,

an electrical power supply unit which supplies individual components of the system with energy, and

an output-side electromechanical transducer arrangement which is comprised of at least two independent and spatially separate transducers, an output-side of which is adapted for stimulation of fluid-filled inner ear spaces of a damaged inner ear of a patient in an implanted state,

wherein the signal processing unit comprises driving signal processing electronics which electrically controls each of the transducers in a manner causing a traveling wave configuration to be formed on a basilar membrane of the damaged inner ear which approximates the manner of a traveling wave configuration of a healthy, undamaged inner ear.

2. The system of claim 1, wherein the transducers of the output-side electromechanical transducer arrangement are adapted to produce direct stimulation of the fluid-filled inner ear spaces of the damaged inner ear.

3. The system of claim 2, wherein the transducers of the output-side electromechanical transducer arrangement are output-side electromechanical transducers that are part of an intracochlear transducer array.

4. The system of claim 3, wherein the intracochlear transducer array has an outer diameter in a range from 0.4 mm to 2.0 mm.

5. The system of claim 3, wherein a total length of the intracochlear transducer array is between 5 mm and 50 mm.

6. The system of claim 3, wherein the intracochlear transducer array has a carrier of biocompatible material which is bio-stable in the inner ear.

7. The system of claim 6, wherein the electromechanical transducers are completely embedded in the carrier surrounded by a thin layer of the carrier material.

8. The system of claim 6, wherein mechanical attenuation elements are embedded in the carrier between the electromechanical transducers for minimizing mechanical wave propagation within the carrier between adjacent transducers.

9. The system of claim 8, wherein the attenuation elements are made of a material having a large mechanical impedance difference as compared to material of the carrier in order to achieve high attenuation values.

10. The system of claim 2, wherein the transducers of the extracochlear transducer array each have an output-side coupling element which is adapted to project through an opening of a cochlear wall into the fluid-filled inner ear space in an implanted state.

11. The system of claim 3, wherein the output-side electromechanical transducers in the transducer array are arranged in an equidistant distribution.

12. The system of claim 3, wherein the output-side electromechanical transducers in the transducer array are arranged at logarithmic distances according to a tonotopic frequency-location assignment.

13. The system of claim 12, wherein the transducer array comprises between 20 and 24 output-side electromechanical transducers in conformity with psychoacoustic critical bands.

14. The system of claim 1, wherein the transducers of the output-side electromechanical transducer arrangement are formed into an extracochlear array of output-side electromechanical transducers.

15. The system of claim 14, wherein the extracochlear transducer array is formed of Microsystems components.

16. The system of claim 15, wherein the extracochlear transducer array further comprises a substrate which contains a printed circuit electrical terminal panel for connection of a multipole, biocompatible implant lead to a module which contains driving signal processing electronics.

17. The system of claim 15, wherein the extracochlear transducer array further comprises a substrate which contains a printed circuit electronic module.

18. The system of claim 17, wherein the electronic module contains driver stages for controlling the output-side electromechanical transducers.

19. The system of claim 17, wherein the electronic module contains decoding logic and transducer modules for connection of a minimum pole implant lead.

20. The system of claim 19, wherein the array has a terminal comprised of a ground line, a data line and a clock signal line, and wherein supply of electrical operating energy takes place by phantom feed on the clock signal line.

21. The system of claim 19, wherein the array has a terminal comprised of a ground line, a data line and a clock signal line, and wherein supply of electrical operating energy takes place by rectifying the clock signal directly.

22. The system of claim 17, wherein the electronic module contains an interface module for digital data transmission via the implant lead.

23. The system of claim 17, wherein the electronic module contains corresponding digital-analog converters and driver modules assigned to the transducers for serial data transmission on the implant feed line.

24. The system of claim 17, wherein the extracochlear transducer array including the carrier structure is equipped with biocompatible coating.

25. The system of claim 17, wherein the output-side electromechanical transducers are piezoelectric transducers made of a material selected from the group consisting of lead zirconate titanate ceramics or polyvinylidene fluoride.

26. The system of claim 1, wherein the output-side electromechanical transducers are transducers selected from the group consisting of electromagnetic, electrodynamic, piezoelectric, magnetostrictive or dielectric transducers.

27. The system of claim 1, wherein the output-side electromechanical transducers are adapted to provide maximum deflection with minimum electric power consumption at a given transducer voltage.

28. The system of claim 1, wherein the transducers of the output-side electromechanical transducer arrangement have a transmission range from about 100 Hz to about 10 kHz.

29. The system of claim 1, wherein the transducers of the output-side electromechanical transducer arrangement are tuned to have first mechanical resonant frequency at an upper end of a desired transmission frequency range.

30. The system of claim 1, wherein the transducers of the output-side electromechanical transducer arrangement are hermetically sealed.

31. The system of claim 1, wherein the signal processing unit has a preprocessing arrangement designed for analog-digital conversion of the acoustic sensor signals and for at least one function selected from the group consisting of pre-amplification or filtering of the acoustic sensor signals.

32. The system of claim 31, wherein the preprocessing arrangement comprises an antialiasing filter.

33. The system of claim 1, wherein said at least one acoustic sensor comprises a plurality of acoustic sensors, each of which has analog-digital converter associated therwith.

34. The system of claim 1, wherein the signal processing unit comprises software modules adapted to mask tinnitus during operation of the system.

35. The system of claim 34, wherein a preprogrammed read-only memory area is assigned to the signal processor.

36. The system of claim 1, comprising at least one digital-analog converter connected to an input of the output-side electromechanical transducer arrangement.

37. The system of claim 1, wherein the signal processing electronics comprise software modules which control the output-side electromechanical transducer arrangement achieving spectral, time, amplitude- and phase-referenced transducer signal properties that are dimensioned so as to produce, in an implanted state, a traveling wave at a basilar membrane of the damaged inner ear that approximates that of healthy hearing.

38. The system of claim 37, wherein the software modules are static software modules which are stored in a program storage of the digital signal processor and remain unchanged.

39. The system of claim 37, comprising a wireless telemetry means for transmission of data between the implanted part of the system and an external unit, wherein the software modules are adaptive, being changeable after being stored in a program storage of the digital signal processor.

40. The system of claim 39, wherein the software modules are adaptive for parameter matching in an implanted stated by training conducted by an implant wearer.

41. The system of claim 1, wherein the signal processing unit comprises a digital signal processor which provides for at least one function selected from the group consisting of processing analog-digital-converted acoustic sensor signals or generation of digital signals for tinnitus masking.

42. The system of claim 41, comprising a microprocessor module for control of at least one of a digital-analog converter, said analog-digital converter, and said signal processor, via a data bus.

43. The system of claim 42, wherein an implantable storage arrangement for storage of an operating program for the microprocessor module is assigned to the microprocessor module, and at least one of a plurality of parts of the operating program for the microprocessor module are adapted to be replaced by data transferred from the external unit via the telemetry means.

44. The system of claim 1, wherein the signal processing unit comprises a software module for approximate simulation of a healthy cochlear amplifier based on an adaptive neural network.

45. The system of claim 44, wherein the principle of time-reversed acoustics is implemented in the neural network for simulation of a healthy cochlear amplifier, and control of the output-side electromechanical transducers takes place by time-reversed acoustics such that locally limited areas of the cochlea are mechanically stimulated.

46. The system of claim 1, comprising a wireless telemetry means for transmission of data between the implanted part of the system and an external unit.

47. The system of claim 46, comprising a microprocessor module for control of at least one of a digital-analog converter, an analog-digital converter, and said signal processing unit via a data bus, wherein at least one of a plurality of program parts are adapted to be transferred between an external source, the microprocessor module and the signal processor via the data bus and the telemetry means.

48. The system of claim 46, wherein the telemetry means is adapted transmission of operating parameters between the implantable part of the system and the external unit.

49. The system of claim 46, wherein a rewritable implantable storage arrangement is assigned to the signal processor for storage and retrieval of an operating program and at least parts of the operating program are adapted to be at least partially replaced by data transmitted from the external unit via the telemetry means.

50. The system of claim 49, comprising at least two storage areas for storage and retrieval of at least said operating program of the signal processor.

51. The system of claim 49, further comprising a buffer storage arrangement in which data transmitted from the external unit via the telemetry means are buffered before being relayed to the signal processor.

52. The system of claim 51, further comprising a checking logic for checking data stored in the buffer storage arrangement before said data are relayed to the signal processor.

53. The system of claim 52, comprising a microprocessor module for control of at least one of a digital-analog converter, said analog-digital converter, and said signal processing unit, via a data bus;

wherein the checking logic and the buffer storage arrangement are implemented in the microprocessor module.

54. The system of claim 51, wherein the buffer storage arrangement comprises at least two storage areas for storage and retrieval of data transferred from the external unit via the telemetry means.

55. The system of claim 1, wherein the electrical power supply unit comprises an implantable rechargeable energy storage element, and wherein the system is totally implantable except for a wireless, transcutaneous charging device which is provided for charging of the storage element.

56. The system of claim 55, comprising a wireless remote control for control of implant functions by the implant wearer.

57. The system of claim 1, wherein the system is partially implantable, wherein said at least one acoustic sensor, said electronic arrangement for audio signal processing and amplification, said power supply unit and a modulator/transmitter unit is contained in an external module to be worn externally on the body a user, and wherein the electromechanical transducer arrangement is an implantable passive unit which receives operating energy and transducer control data via the modulator/transmitter unit in the external module.

58. The system of claim 1, wherein the system is a binaural system for rehabilitation of a hearing disorder of both ears and has two system units, one each for each of two ears of a wearer.

59. The system of claim 58, wherein the two system units are essentially equal to one another.

60. The system of claim 58, wherein one system unit is master unit and the other system unit is slave unit which is controlled by the master unit.

61. The system of claim 58, comprising a wired implantable line connection by which the signal processing modules communicate with one another for optimizing binaural signal processing and transducer array control in both system units.

62. The system of claim 58, comprising a wireless connection by which the signal processing modules communicate with one another for optimizing binaural signal processing and transducer array control in both system units.

63. The system of claim 58, wherein the signal processing unit of both system units communicate with one another via an ultrasonic path adapted to be coupled, in an implanted stated, by bone conduction for optimizing binaural signal processing and transducer array control in both system units.

64. The system of claim 58, wherein implantable electrodes are assigned to the signal processing unit and the implantable electrodes are adapted, in the implanted state, to form part of a data transmission path body tissue of the implant wearer for communication of the signal processing units of the two system units.

65. The system of claim 1, wherein said at least one electromechanical transducer is hollow body adapted to undergo a dynamic volume change when a voltage signal is applied.

66. The system of claim 1, wherein said at least one electromechanical transducer is housed in a hose-shaped carrier which is provided with at least one opening for the passage of intracochlear fluid, said at least one opening being adjacent to at least one end of the transducer.