# US 2022/0031996 A1 · Noise cancellation for balance prosthesis

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- Number: US 2022/0031996 A1
- Document ID: US20220031996A1
- Status: Published application
- Kind: A1
- Application number: 17/299,570
- Filed: 2020-04-27
- Published: 2022-02-03
- Earliest claimed: 2019-05-07
- Applicants: Cochlear Limited
- Inventors: Koen Erik Van den Heuvel; Joerg Pesch
- Web page: https://patentgrep.com/patent/US20220031996A1

## CPC

- A61M 21/00: Other devices or methods to cause a change in the state of consciousness; Devices for producing or ending sleep by mechanical, optical, or acoustical means, e.g. for hypnosis
- A61N 1/36036: {of the outer, middle or inner ear}
- A61B 5/4851: {Prosthesis assessment or monitoring}
- A61B 5/721: {using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured}
- A61N 1/36139: {with automatic adjustment}
- A61B 2562/0219: Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
- A61M 2021/0005: {by the use of a particular sense, or stimulus}
- A61M 2205/0244: Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
- A61M 2205/04: implanted
- A61M 2205/3327: Measuring
- A61M 2205/42: Reducing noise
- H04R 25/407: {Circuits for combining signals of a plurality of transducers}
- H04R 2225/61: Aspects relating to mechanical or electronic switches or control elements, e.g. functioning
- H04R 2225/67: Implantable hearing aids or parts thereof not covered by H04R25/606
- H04R 2460/13: Hearing devices using bone conduction transducers
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

A system is provided which includes at least one first sensor subsystem configured to be worn on or implanted within a recipient's head and to generate first signals indicative of motion of the head and vibrational noise experienced by the recipient. The system further includes at least one second sensor subsystem spaced from the at least one first sensor subsystem. The second sensor subsystem is configured to generate second signals at least partially indicative of the vibrational noise experienced by the recipient. The system further includes signal processing circuitry configured to receive the first signals and the second signals, to filter the first signals in response at least in part to the second signals, and to generate third signals indicative of the motion of the head.

## Claims

### Claim 1

A system comprising:
at least one first sensor subsystem configured to be worn on or implanted within a recipient's head and to generate first signals indicative of motion of the head and vibrational noise experienced by the recipient;
at least one second sensor subsystem spaced from the at least one first sensor subsystem, the second sensor subsystem configured to generate second signals at least partially indicative of the vibrational noise experienced by the recipient; and
signal processing circuitry configured to receive the first signals and the second signals, to filter the first signals in response at least in part to the second signals, and to generate third signals indicative of the motion of the head.

### Claim 2 (depends on 1)

The system of claim 1, wherein at least one of the at least one first sensor subsystem and the at least one second sensor subsystem comprises a plurality of microelectromechanical system (MEMS) sensors.

### Claim 3 (depends on 1)

The system of claim 1, wherein the at least one first sensor subsystem comprises at least one accelerometer and the first signals are at least partially indicative of accelerations of the head.

### Claim 4 (depends on 1)

The system of claim 1, wherein the at least one first sensor subsystem comprises at least one gyroscope and the first signals are at least partially indicative of rotations of the head.

### Claim 5 (depends on 1)

The system of claim 1, wherein the third signals are indicative of the motion of the head relative to three orthogonal axes.

### Claim 6 (depends on 1)

The system of claim 1, wherein the at least one second sensor subsystem comprises at least one accelerometer and/or at least one gyroscope.

### Claim 7 (depends on 1)

The system of claim 1, wherein the at least one second sensor subsystem is worn or carried by the recipient below the recipient's neck.

### Claim 8 (depends on 1)

The system of claim 1, wherein the at least one second sensor subsystem is mounted within an electronic device carried by the recipient or within a vehicle carrying the recipient.

### Claim 9 (depends on 1)

The system of claim 1, wherein the signal processing circuitry is configured to adaptively filter the first signals.

### Claim 10 (depends on 1)

The system of claim 1, wherein the signal processing circuitry comprises:
filtering circuitry configured to receive the second signals and to generate filtering signals in response at least in part to the second signals; and
summation circuitry configured to receive the first signals and the filtering signals and to generate the third signals in response to the first signals and the filtering signals.

### Claim 11 (depends on 10)

The system of claim 10, wherein the filtering circuitry is further configured to receive the third signals and to generate the filtering signals in response to the second signals and the third signals.

### Claim 12 (depends on 10)

The system of claim 10, wherein the summation circuitry comprises:
an adder configured to add the filtering signals to the first signals to generate resultant signals; and
an automatic gain controller configured to apply a gain to the resultant signals to generate the third signals.

### Claim 13 (depends on 1)

The system of claim 1, further comprising an output assembly configured to receive the third signals and to communicate sensory signals to the recipient, the sensory signals generated in response to the third signals and configured to be perceived by the recipient.

### Claim 14 (depends on 1)

The system of claim 1, wherein the system comprises a balance prosthesis.

### Claim 15

A method comprising:
receiving first signals having a first component indicative of first movements of a head of a recipient in a first frequency range and a second component indicative of second movements of the head in a second frequency range;
receiving second signals at least partially indicative of the second movements; and
generating third signals by adaptively filtering the first signals in response, at least in part, to the second signals, the third signals indicative of the first signals with the second component suppressed.

### Claim 16 (depends on 15)

The method of claim 15, wherein both the first movements and second movements comprise translations and/or rotations of the head relative to three orthogonal axes.

### Claim 17 (depends on 15)

The method of claim 15, wherein the filtering is selected from the group consisting of: least mean squares (LMS) filtering; normalized least mean squares (NLMS) filtering; recursive least squares (RLS) filtering; affine projection algorithm (APA) filtering.

### Claim 18 (depends on 15)

The method of claim 15, wherein the first frequency range is less than or equal to 25 Hz and the second frequency range is greater than 25 Hz.

### Claim 19 (depends on 15)

The method of claim 15, wherein the first signals are received from a first sensor subsystem worn on or implanted within a recipient's head, the second signals are received from second sensor subsystem spaced from the first sensor subsystem and not worn on or implanted within the recipient's head, the method further comprising determining a relative orientation of the first sensor subsystem to the second sensor subsystem.

### Claim 20

A method comprising:
receiving at least one first orientation signal from a first sensor array comprising at least one first accelerometer, the at least one first orientation signal indicative of a direction of gravity relative to a first coordinate system of the first sensor array;
receiving at least one second orientation signal from a second sensor array comprising at least one second accelerometer spaced from the at least one first accelerometer, the at least one second orientation signal indicative of the direction of gravity relative to a second coordinate system of the second sensor array;
determining, in response to the at least one first orientation signal and the at least one second orientation signal, a relative orientation between the first coordinate system and the second coordinate system; and
using the relative orientation to transform first motion signals received from the first sensor array indicative of motion of the first sensor array relative to the first coordinate system and/or to transform second motion signals received from the second sensor array indicative of motion of the second sensor array relative to the second coordinate system such that the first motion signals and the second motion signals correspond to motions of the first sensor array and the second sensor array, respectively, relative to a common coordinate system.

### Claim 21 (depends on 20)

The method of claim 20, wherein receiving the at least one first orientation signal is performed while the first sensor array is stationary and receiving the at least one second orientation signal is performed while the second sensor array is stationary.

### Claim 22 (depends on 20)

The method of claim 20, wherein receiving the at least one first orientation signal and receiving the at least one second orientation signal are performed concurrently.

### Claim 23 (depends on 20)

The method of claim 20, further comprising monitoring motions of the first sensor array and the second sensor array to detect changes of the relative orientation, updating the relative orientation, and using the updated relative orientation to transform the first motion signals and/or the second motion signals.

### Claim 24 (depends on 20)

The method of claim 20, wherein the first sensor array further comprises at least one first gyroscope and the first motion signals received from the first sensor array are indicative of translations of the first sensor array along each of three orthogonal axes of the first coordinate system and of rotations of the first sensor array about each of the three orthogonal axes of the first coordinate system.

### Claim 25 (depends on 24)

The method of claim 24, wherein the second sensor array further comprises at least one second gyroscope and the second motion signals received from the second sensor array are indicative of translations of the second sensor array along each of three orthogonal axes of the second coordinate system and of rotations of the second sensor array about each of the three orthogonal axes of the second coordinate system.

### Claim 26 (depends on 20)

The method of claim 20, wherein the first sensor array is configured to be worn on or implanted within a recipient's head.

### Claim 27 (depends on 26)

The method of claim 26, wherein the second sensor array is configured to be worn on or carried by a recipient spaced from the first sensor array or mounted on a vehicle carrying the recipient.