Optical full-implantation artificial cochlea

Abstract

The invention discloses an optical fully-implanted artificial cochlea, which comprises a laser transceiving unit, a sound signal processing unit, an electrode array unit, a dual-mode coil unit and a built-in battery, and is characterized in that the laser transceiving unit is implanted into a middle ear cavity, is used for transmitting and receiving laser signals and comprises a transmitting end and a receiving end, the transmitting end continuously transmits laser to a tympanic membrane, and the receiving end is used for receiving the laser signals; the tympanic membrane vibrates to modulate the optical signal; the receiving end carries out demodulation and signal extraction on the reflected light; the sound signal processing unit is implanted under the skin behind the ear and is used for extracting and coding the characteristics of sound signals; the electrode array unit is implanted into the cochlea, and sound signals are transmitted by electrically stimulating auditory nerve elements in the cochlea; the dual-mode coil unit is implanted under the skin behind the ear and is used for wireless transmission of external signals and wireless charging energy complementation. According to the invention, efficient and fidelity transmission and processing of sound are realized, so that the existing artificial cochlea technology is thoroughly innovated, and more natural and comfortable auditory experience is provided for hearing impairment patients.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to an optically fully implantable cochlear implant. Background Art

[0002] Hearing impairment is a major issue that affects the quality of life of a large number of people around the world. Although traditional cochlear implant systems have helped deaf patients regain their hearing to a certain extent, their design has many limitations. First, the external device needs to be worn by the patient at all times, which not only increases the daily burden, but is also easy to be lost or damaged during exercise or daily activities, causing inconvenience to the patient. Secondly, the presence of the external device makes the deaf patient easy to be identified by the outside world, which may cause psychological pressure and inferiority. In addition, the external device needs to be replaced or repaired regularly, which increases the financial burden on the patient. At the same time, traditional cochlear implants may produce distortion during sound collection and transmission, affecting the auditory experience. In addition, compared with traditional implantable microphones, there are problems such as low sound pickup accuracy, poor signal-to-noise ratio, strong dependence on implantation position, susceptibility to biological tissue wrapping or liquid interference, and long-term implantation has the risk of causing infection or foreign body reaction. The present invention uses laser modulation of tympanic membrane vibration for sound collection, which can effectively overcome the limitations of traditional microphone methods and significantly improve the fidelity of sound collection and the long-term stability of the system. Summary of the Invention

[0003] The purpose of this invention is to provide a new fully implantable cochlear implant that uses advanced optical modulation and laser detection technology to achieve efficient and fidelity transmission and processing of sound, thereby completely revolutionizing existing cochlear implant technology and providing hearing-impaired patients with a more natural and comfortable auditory experience.

[0004] To achieve the above-mentioned object of the invention, the present invention provides an optical fully implantable cochlear implant, comprising a laser transceiver unit, an audio signal processing unit, an electrode array unit, a dual-mode coil unit, and a built-in battery, wherein:

[0005] The laser transceiver unit is implanted in the middle ear cavity and is used to transmit and receive laser signals. It includes a transmitter and a receiver. The transmitter is facing the eardrum and continuously emits laser light to the eardrum. The eardrum vibration modulates the light signal. The receiver collects the reflected light signal modulated by the eardrum vibration and combines coherent detection technology to demodulate and extract the reflected light signal to obtain the modulation information corresponding to the original sound signal.

[0006] The sound signal processing unit is implanted subcutaneously behind the ear and is used for feature extraction and encoding of sound signals;

[0007] The electrode array unit is implanted in the cochlea and transmits sound signals by electrically stimulating auditory neurons in the cochlea;

[0008] The dual-mode coil unit is implanted subcutaneously behind the ear for wireless transmission of external signals and wireless charging;

[0009] A built-in battery is implanted subcutaneously behind the ear to provide power.

[0010] Furthermore, the calculation formula for the modulation of the light signal by the eardrum vibration is:

[0011] ,

[0012] Where E0 is the amplitude of the original emitted laser, f0 is the laser carrier frequency, x(n) is the eardrum vibration displacement, λ is the laser wavelength, and E mod (n) is the optical signal modulated by eardrum vibration.

[0013] Furthermore, the receiving end demodulates and extracts the reflected light signal, uses coherent interferometry technology to demodulate the reflected light signal, and reconstructs the sound waveform by analyzing the interference result between the reflected light and the local reference light, where the sound signal is:

[0014] ,

[0015] where Z m is the mechanical impedance of the eardrum, x(n) is the vibration displacement of the eardrum measured after demodulation, and s(n) is the reconstructed sound signal.

[0016] Furthermore, the sound signal processing unit processes the sound signal restored by the receiving end, including the following steps:

[0017] Step S1: Perform discrete Fourier transform on the reconstructed sound signal s(n):

[0018]

[0019] Where N is the length of a frame and k is the frequency index;

[0020] Step S2, X i (k) Calculate the amplitude and phase X i_angle (k), the first frame signal is used as the average energy D(k) of the noise segment, and the formula is expressed as:

[0021] ;

[0022] Where k is the frequency index;

[0023] Step S3: Filter the sound signal restored by the receiving end and use spectral subtraction to suppress background noise. The calculation formula of spectral subtraction is:

[0024] ,

[0025] in is the estimated power spectrum of a frame, |X i (k)| 2 is the power spectrum of the actual signal, a is the over-subtraction factor, b is the gain compensation factor, and D(k) is the noise energy;

[0026] Step S4, perform inverse Fourier transform to obtain the speech signal after spectral subtraction noise reduction, which is expressed as:

[0027] ;

[0028] Where N is the length of a frame, j is the imaginary unit, 2 =-1;

[0029] In step S5, the speech sequence s(n) after spectral subtraction and enhancement is obtained by using IFFT (Inverse Fast Fourier Transform) in combination with the saved phase.

[0030] Furthermore, the sound signal processing unit performs signal frequency division on the sound signal, decomposing the sound signal into 22 frequency segments, each frequency segment corresponding to a position in the cochlea; the sound signal processing unit extracts and calculates the signal energy of each frequency segment, generates corresponding current parameters to adapt to the stimulation requirements of the electrode array, and the calculation formula for signal frequency division is:

[0031] ,

[0032] Wherein, w(nt) is the window function, S(t, f) represents the energy value at time t and frequency, and s(n) is the enhanced speech sequence.

[0033] Furthermore, the energy calculation formula for each frequency band is:

[0034] ,

[0035] Among them, E k is the electrical stimulation parameter of the kth channel, and k corresponds to the number of channels in the electrode array.

[0036] Compared with the prior art, the present system and method have the following advantages:

[0037] 1. This invention adopts a fully implantable design, eliminating the external device and integrating all functions, which greatly improves the convenience and aesthetics of use and reduces the psychological burden on patients.

[0038] 2. The present invention adopts high-precision sound acquisition. The laser emitting unit and the laser receiving unit are directly aimed at the eardrum. When the eardrum vibrates, the light signal is modulated without error, achieving high-precision acquisition of sound signals.

[0039] 3. This invention uses optical modulation and laser detection technology. Laser technology transmits sound information through light signals, avoiding the signal attenuation and interference caused by traditional electrical signals during transmission in the middle ear, and improving the resolution of sound signals.

[0040] 4. The present invention eliminates the cost of frequent replacement of external devices and reduces the financial burden on patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the structure of an optically fully implantable cochlear implant. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] like Figure 1 The figure shows a schematic diagram of the structure of the present invention. An embodiment of the present invention provides an optically fully implantable cochlear implant, comprising an optical cochlear implant consisting of five parts: a laser transceiver unit 1, a sound signal processing unit 2, an electrode array unit 5, a dual-mode coil unit 3, and a built-in battery 4. The laser transceiver unit 1 is responsible for transmitting and receiving laser signals, the sound signal processing unit 2 is responsible for feature extraction and encoding of sound signals, the electrode array unit 5 transmits sound signals by electrically stimulating auditory neurons in the cochlea, the dual-mode coil 3 (receiving coil and charging coil) unit realizes wireless transmission of external signals and battery power supply, and the built-in battery 4 provides power support for each component.

[0044] The surgical implantation details are as follows:

[0045] The dual-mode coil unit 3, the sound signal processing unit 2, and the built-in battery unit 4 are implanted subcutaneously behind the ear; the laser transceiver unit 1 is implanted in the middle ear cavity; and the electrode array unit 5 is implanted in the cochlea.

[0046] When the system is working properly, external sound is transmitted to the eardrum through the external auditory canal. The sound vibration causes a tiny mechanical vibration of the eardrum. The transmitting end of the laser transceiver unit 1 is facing the eardrum of the human ear, and can emit a laser to transmit to the eardrum. The energy of the light beam is controlled within a safe range and does not cause damage to the eardrum or middle ear tissue. Due to the uniform surface structure and sensitive response of the eardrum, its mechanical vibration will produce a modulation effect on the laser signal, thereby achieving the modulation of the sound signal to the phase of the light wave. Among them, the calculation formula for the modulation of the light signal by the eardrum vibration is:

[0047] ,

[0048] Where E0 is the amplitude of the original emitted laser, f0 is the laser carrier frequency, x(n) is the eardrum vibration displacement, λ is the laser wavelength, E mod (n) is the optical signal modulated by eardrum vibration.

[0049] The receiving end of the laser transceiver unit 1 collects the reflected light signal modulated by the eardrum vibration, and combines the coherent detection technology to perform interference demodulation and signal extraction on the reflected light. That is, the coherent interferometry measurement technology is used to demodulate the light signal, and by analyzing the interference result of the reflected light and the local reference light, the modulation information corresponding to the original sound signal is obtained, thereby reconstructing the sound waveform without contact. The sound signal is:

[0050] ,

[0051] Z m is the mechanical impedance of the eardrum, x(n) is the vibration displacement of the eardrum measured after demodulation, and s(n) is the reconstructed sound signal.

[0052] The sound signal processing unit 2 filters the sound signal restored by the receiving end and suppresses background noise using spectral subtraction, including the following steps:

[0053] Step S1: Perform discrete Fourier transform (DFT) on the reconstructed sound signal s(n):

[0054]

[0055] Where N is the frame length, which is usually 256, and k is the frequency index.

[0056] Step S2, X i (k) Calculate the amplitude and phase X i_angle (k), the first frame signal is used as the average energy D(k) of the noise segment, and the formula is expressed as:

[0057] ;

[0058] Where k is the frequency index.

[0059] Step S3: Filter the sound signal restored by the receiving end and use spectral subtraction to suppress background noise. The calculation formula of spectral subtraction is:

[0060] ,

[0061] in is the estimated power spectrum of a frame, |X i (k)| 2is the power spectrum of the actual signal, which is generally taken as 4, b is the gain compensation factor, which is generally taken as 0.001, and D(k) is the noise energy.

[0062] Step S4, combining the saved phase X i_angle (k), perform inverse Fourier transform to obtain the speech signal after spectral subtraction noise reduction, which can be expressed as:

[0063] ;

[0064] Where N is the frame length, usually 256, j is the imaginary unit, 2 =-1.

[0065] Step S5: Combine the stored phase and use IFFT to obtain the speech sequence s(n) after spectral subtraction and enhancement.

[0066] The sound signal processing unit 2 performs signal frequency division, that is, the sound signal is decomposed into 22 frequency segments, each frequency segment corresponds to a position in the cochlea; the signal energy of each frequency segment is extracted and calculated, and the corresponding current parameters are generated to adapt to the stimulation requirements of the electrode array. The sound signal processing unit 2 finally outputs the current output parameters corresponding to the 22 frequency segments of the human ear to the electrode array unit 5 to stimulate the auditory neurons, and performs precise current stimulation at the corresponding frequency position of the cochlea to induce auditory nerve impulses, so that the auditory center can perceive external sounds. The calculation formula for signal frequency division is:

[0067] ,

[0068] Wherein, w(n) is the window function, S(t, f) represents the energy value at time t and frequency, and s(n) is the enhanced speech sequence obtained in the previous step S5.

[0069] Energy extraction is used to calculate the energy of each frequency band. The calculation formula is:

[0070] ,

[0071] Among them, E k That is, the electrical stimulation parameter of the kth channel, where k corresponds to the number of channels in the electrode array, which is 22 in the embodiment.

[0072] The power required for the system to operate is used to wirelessly charge the built-in battery 4 through the dual-mode coil unit 3, without the need for frequent disassembly or external replacement, further improving the convenience and safety of use. At the same time, the dual-mode coil 3 can also be used to receive external wireless signals.

[0073] The embodiments of the present invention have been specifically described above, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without departing from the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An optically fully implantable cochlear implant, characterized in that: It includes a laser transceiver unit, a sound signal processing unit, an electrode array unit, a dual-mode coil unit, and a built-in battery, wherein: The laser transceiver unit is implanted in the middle ear cavity and is used to transmit and receive laser signals. It includes a transmitter and a receiver. The transmitter is facing the eardrum and continuously emits laser light to the eardrum. The eardrum vibration modulates the light signal. The receiver collects the reflected light signal modulated by the eardrum vibration and combines coherent detection technology to demodulate and extract the reflected light signal to obtain the modulation information corresponding to the original sound signal. The sound signal processing unit is implanted subcutaneously behind the ear and is used for feature extraction and encoding of sound signals; The electrode array unit is implanted in the cochlea and transmits sound signals by electrically stimulating auditory neurons in the cochlea; The dual-mode coil unit is implanted subcutaneously behind the ear for wireless transmission of external signals and wireless charging; A built-in battery is implanted subcutaneously behind the ear to provide power.

2. The optically fully implantable cochlear implant according to claim 1, wherein: The calculation formula for the modulation of the optical signal by the eardrum vibration is: ， Where E0 is the amplitude of the original emitted laser, f0 is the laser carrier frequency, x(n) is the eardrum vibration displacement, λ is the laser wavelength, and E mod (n) is the optical signal modulated by eardrum vibration.

3. The optically fully implantable cochlear implant according to claim 1, wherein: The receiving end demodulates and extracts the reflected light signal, uses coherent interferometry technology to demodulate the reflected light signal, and reconstructs the sound waveform by analyzing the interference result between the reflected light and the local reference light, where the sound signal is: ， where Z m is the mechanical impedance of the eardrum, x(n) is the vibration displacement of the eardrum measured after demodulation, and s(n) is the reconstructed sound signal.

4. The optically fully implantable cochlear implant according to claim 3, characterized in that: The sound signal processing unit processes the sound signal restored by the receiving end, including the following steps: Step S1: Perform discrete Fourier transform on the reconstructed sound signal s(n): Where N is the length of a frame and k is the frequency index; Step S2, X i (k) Calculate the amplitude and phase X i_angle (k), the first frame signal is used as the average energy D(k) of the noise segment, and the formula is expressed as: ； Where k is the frequency index; Step S3: Filter the sound signal restored by the receiving end and use spectral subtraction to suppress background noise. The calculation formula of spectral subtraction is: ， in is the estimated power spectrum of a frame, |X i (k)| 2 is the power spectrum of the actual signal, a is the over-subtraction factor, b is the gain compensation factor, and D(k) is the noise energy; Step S4: perform inverse Fourier transform to obtain the speech signal after spectral subtraction noise reduction, which is expressed as: ； Where N is the length of a frame, j is the imaginary unit, 2 =-1; Step S5: Combine the stored phase and use IFFT to obtain the speech sequence s(n) after spectral subtraction and enhancement.

5. The optically fully implantable cochlear implant according to claim 4, characterized in that: The sound signal processing unit performs signal frequency division on the sound signal, decomposing the sound signal into 22 frequency segments, each frequency segment corresponding to a position in the cochlea; the sound signal processing unit extracts and calculates the signal energy of each frequency segment, and generates corresponding current parameters to adapt to the stimulation requirements of the electrode array. The calculation formula for signal frequency division is: ， Wherein, w(nt) is the window function, S(t, f) represents the energy value at time t and frequency, and s(n) is the enhanced speech sequence.

6. The optically fully implantable cochlear implant according to claim 5, characterized in that: The energy calculation formula for each frequency band is: ， Among them, E k is the electrical stimulation parameter of the kth channel, and k corresponds to the number of electrode array channels.

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