Bone Conduction Hearing Devices

Question 1

What are bone conduction hearing devices?

Answer 1

Amplifies sound through bone conduction, serving as an alternative to a regular hearing aid for those with problems in their outer and middle ears
It transfers sound by bone vibration directly to the cochlea, bypassing the outer and the middle ear
Fixed to the head by means of an elastic band or a surgically implanted internal component
The external component captures background noise and makes its sound reach the cochlea through mechanical amplification

Question 2

When did bone conduction hearing originate?

Answer 2

Ancient times
Legend has it that Beethoven continued composing music despite hearing loss by using a tuning fork pressed against his head, relying on bone conduction to hear

Question 3

Do multiple physiologic mechanisms contribute to bone conduction hearing?

Answer 3

Yes, includes 5 major pathways that contribute to hearing through bone conduction
Sound radiation to the external ear canal
Middle ear ossicle inertia
Inertia of cochlear fluids
Compression of the cochlear walls (or inner ear compression)
Pressure transmission from cerebrospinal fluid (CSF)

Question 4

What is a BAHA?

Answer 4

Acronym for bone-anchored hearing aids
Bone conduction hearing devices is replacing this term due to technological advancements
BAHA is a brand name of cochlear

Question 5

When did the first bone-anchored hearing device become widely commercially available?

Answer 5

In the 1980s
Since this, patients with CHL, MHL, and those with SSD have benefitted from these devices

Question 6

What are the two components of bone anchored hearing devices?

Answer 6

An external sound processor that captures acoustic signals, converts the acoustic signal to analogous mechanical vibrations, and delivers the mechanical vibrations to the internal component
A titanium component that is surgically implanted in the skull and used to deliver mechanical vibrations to the cochlear via bone conduction

Question 7

What kind of transducer is used for bone anchored hearing devices?

Answer 7

Electromagnetic transducer
Converts electrical current into mechanical energy

Question 8

What are the two ferrite components for the electromagnetic transducer?

Answer 8

Armature that is surrounded by wired coils and contains a permanent magnet that allows to move when stimulated electrical currents
Yoke which remains fixed and does not move

Question 9

How does the electromagnetic transducer work?

Answer 9

When an electrical current is delivered through coils surrounding the armature, a magnetic field is generated in the underlying ferrite material
Fluctuations in the strength and frequency of the current create an oscillating magnetic field, causing the magnetic field between the armature and the yoke to change
This alternately attracts and repels the armature to and from the yoke
This movement creates mechanical energy in the transducer that may be transmitted to the skull when the sound processor is coupled to the head

Question 10

Are the transducers in modern bone conduction devices significantly more complex?

Answer 10

Yes

Question 11

What are some complications that can arise from bone anchored hearing devices?

Answer 11

Peri-implant infection
Flap necrosis
Loss of abutment (infection or trauma)
Osseointegration failure
Cosmetic factors
Skin numbness
Skin overgrowth over the abutment which makes it impossible to use the processor

Question 12

What is the holgers classification system?

Answer 12

Grades soft tissue reactions at the implant site
Grades from 0 (reaction free) to 4 (overt signs of infection resulting in removal of implant)

Question 13

What are the two types of bone conduction devices?

Answer 13

Direct drive and skin drive

Question 14

What is direct drive?

Answer 14

Vibrations are directly transmitted to the bone through an implanted transducer, without the need for skin transmission
Skin will cause attenuation

Question 15

What is skin drive?

Answer 15

Vibrations are transmitted to the bone through the skin via an external devices placed on the skin surface
Intact skin

Question 16

What are active transducers?

Answer 16

Transducer implanted
Implant generates vibration that is directly applied to the bone (direct drive bone conduction)
Optimum BC sound transmission

Question 17

What are passive transducers?

Answer 17

Transducer is impeded in the speech processor
Sound processor generates stimulation that is applied from outside onto the skin
Less optimal; skin attenuates sound before it reaches the bone

Question 18

What does percutaneous mean?

Answer 18

Penetrating the skin
Per- means through (the skin)
What people refer to as BAHA

Question 19

What does transcutaneous mean?

Answer 19

Across the skin
The vibrations from the sound processor are transmitted across the skin
Trans = across
Keeps the skin intact

Question 20

What is osseointegration?

Answer 20

Refers to the process in which bone cells attach/adhere to the surface of a metal (titanium) surface
The bone of the implant site frows into the implant screw forming a biologic attachment
The concept of osseointegration was pioneered by PI Branemark, which described the formation of a natural bond between titanium and bone

Question 21

What are the two broad categories of bone-anchored devices?

Answer 21

Osseointegrated (implants require surgically placing an implant screw that integrates with the temporal bone)
Non-osseointegrated (implants are attached to the bone of the skull, but do not rely on osseointegration for the function of the device)

Question 22

How can connection with external components with an osseointegrated device be achieved?

Answer 22

Transcutaneous abutment or magnetic attachment

Question 23

What are the two stages of osseointegration?

Answer 23

Implant with the abutment is placed as a single piece in one surgical setting
The fixture is implanted in the first stage and the abutment is placed after osseointegration has taken place which is usually 3–6 months

Question 24

What are percutaneous BCD?

Answer 24

A titanium fixture, resembling a screw, is surgically implanted into the skull and osseointegration creates an intimate adherence to the skull bone
The fixture protrudes from the skull and through the skin
Above the skin, the superior end of the fixture contains a threaded hole to which the abutment of the percutaneous may be mounted (i.e., screwed or threaded into or out of the threaded hole at the top of the fixture)

Question 25

What are transcutaneous BCDs?

Answer 25

The titanium component that is implanted into the skull is coupled to a magnetic plate that rests on the top of the skull at the mastoid bone just behind the auricle The device lies completely under the skin, leaving the skin intact The snap coupling of the bone conduction sound processor is connected to a magnetic plate that adheres to the head by way of the magnetic attraction between the external and internal magnets The sound processor oscillates in response to sound stimulation, and the vibrations from the sound processor are transmitted across the skin to the external magnet coupled to the processor and then across the skin and to the magnetic plate that is attached to the fixture Finally, the vibrations transmitted to the fixture radiate throughout the skull and to both cochleae

Question 26

What are advantages for percutaneous implantable BCDs?

Answer 26

Direct transmission results in optimal signal delivery; thresholds are lower by 5-10 dB at 1 and 2 kHz and 10-25 dB at 4-8 kHz (no attenuation from the skin) Beneficial for recipients with skin sensitivity issues exacerbated by transcutaneous device pressure Excellent retention for active recipients Approved for MRI with strength up to 3T Additionally, implant-related artifact/shadow is minimized with the use of only a fixture and not the implantable magnet

Question 27

What are some advantages for transcutaneous BCDs?

Answer 27

Lower rate of complications at and around the incision site Minimal wound care is required Superior aesthetics; invisible Easier attachment and removal Less risk of trauma to the implant Can be activated within four weeks of surgery

Question 28

What are the limitations for percutaneous BCDs?

Answer 28

Heightened risk of abutment-related complications such as extrusion, skin overgrowth, infections, and granulation tissue Need to maintain hygiene at abutment U.S. FDA indicates a 3 to 6 month waiting period between surgery and coupling of processor to abutment in order to allow for osseointegration to occur Protruding abutment may cause aesthetic concerns Difficulty in handling the sound processor may be experienced by recipients with dexterity issues Higher risk of loss from head trauma

Question 29

What are the limitations for transcutaneous BCDs?

Answer 29

Vibrations are transmitted across the skin to a magnet; skin attenuation up to 20 dB, particularly in the high-frequency range (3000 to 8000 Hz) Insufficient power for persons with BC thresholds in the mild to moderate hearing loss range Not cleared for MRI scans with a strength exceeding 1.5 Tesla (T) The implant’s magnetic plate will create significant artifacts/shadowing in and around the implant area Magnet pressure may aggravate scalp soft tissue problems

Question 30

What are the indications for use of percutaneous implantable BCDs?

Answer 30

Ages 5 and older who have a skull thickness of 2.5 mm Individuals with CHL who cannot benefit from conventional hearing aids Individuals with MHL (mixed) with a mild-to-moderate sensorineural component with bone conduction thresholds of 65 dB HL or better (averaged at 500, 1000, 2000, and 3000 Hz Individuals with SSD (single-sided deafness), ideally, the better hearing ear should have bone conduction thresholds of 20 dB HL or better but these implants are generally able to provide enough stimulation that will allow for transfer of the bone-conducted signal to the better hearing ear with thresholds in the mild hearing loss range

Question 31

What are the indications for use of transcutaneous BCDs?

Answer 31

The indications are similar to percutaneous devices, with one key difference: Children should be at least 5 years old, with a skull thickness of at least 2.5 mm and a skin thickness of at least 3 mm Transcutaneous devices are considered for individuals with bone conduction thresholds of 45 dB HL or better, which is more conservative than the criteria for percutaneous devices They are particularly suitable for individuals with conductive hearing loss or single-sided deafness (SSD) with normal bone conduction thresholds in the better hearing ear, as their cochlear hearing sensitivity compensates for any attenuation caused by the skin

Question 32

How do patients care for percutaneous implant sites?

Answer 32

Gently wash his/her hair to avoid skin overgrowth and the development of an infection at the abutment site during the healing period Use an alcohol-free cleaning wipe to keep the skin clean around the abutment Clean the outside of the abutment with warm water and mild soap on a daily basis after the first few weeks following surgery Clean the area around the abutment with the brush provided with the implantable system after the hearing period (4-8 weeks) Bilateral recipients should use a separate cleaning brush for each ear to avoid transmitting potential infection from one ear to the other Monitor and address any redness, soreness, or skin overgrowth

Question 33

How do individuals care for the transcutaneous implant site?

Answer 33

Monitor any redness and address by selecting an appropriate magnet strength

Question 34

Which hearing losses are candidates for BCDs?

Answer 34

CHL Mixed loss Single-sided deafness

Question 35

How is candidacy for BCDs determined?

Answer 35

Based on audiometric evaluation AC pure-tone for each ear from 0.25-8 kHz BC pure-tone thresholds at 0.25, 0.5, 1, 1.5, 2, 3, and 4 kHz (0.5,1,2, and 3 kHz at a minimum) Masked BC thresholds when possible Speech recognition testing for each ear to understand potential benefits from bone conduction devices, although it's not a requirement for candidacy

Question 36

How do you determine candidacy for individuals with CHL/MHL?

Answer 36

Calculate the average BC thresholds and the average ABG Average BC threshold at .5, 1, 2 and 3 kHz; patient is a candidate if ≤ 65 dB HL Additional considerations: Average air-to-bone gap at .5, 1, 2 and 4 kHz; patient is a candidate if >/= 30 dB

Question 37

What is the minimum age for surgical solutions?

Answer 37

5 years and older Non-surgical solutions can be provided at any age

Question 38

How do you determine candidacy for those with single-sided deafness?

Answer 38

Poor ear - profound SNHL equal to or greater than 80 dB HL Good ear - air conduction PTA (0.5, 1, 2, 3 kHz) of less than or equal to 20 dB Work as a cross device, doesn't route signal to poorer ear at all

Question 39

What benefits do candidates experience with mild BC thresholds?

Answer 39

Significant audibility improvement, which those with poorer thresholds may not benefit as much from BCDs

Question 40

What potential benefits will those with unilateral CHL experience?

Answer 40

Efficacy remains uncertain with variability in outcomes Extent of benefit is variable across studies

Question 41

What are the potential benefits of individuals with bilateral CHL?

Answer 41

Significant improvement in audibility, speech recognition in quiet and in noise, and localization

Question 42

What potential benefits will those with single-sided deafness experience?

Answer 42

BCD alleviates the head shadow effect improving speech recognition in quiet and noise when speech arrives from the side of the poorer ear

Question 43

Is it recommended to undergo a listening test with a bone conduction sound processor prior to recommending a bone-anchored device?

Answer 43

Yes, for older children and adults A listening test to demo the bone conduction system can provide a reasonable expectation of the benefit that can be derived from an implantable BCD Preoperative tests can be conducted using various couplers such as soft headband, metal headband, testband, or a proprietary head-worn coupler

Question 44

What are the overall goals for bone conduction device assessment?

Answer 44

Can the device offset the inner ear hearing loss? - done by examining BC thresholds Does a bone-anchored device offer superior benefits compared to traditional hearing aids? - done by administrating listening tests

Question 45

Which listening tests should be done in the sound field for those with CHL and MHL?

Answer 45

Unaided and aided SF warbled tone detection thresholds (determines functional gain) - done btw 0.5-6 kHz Unaided and aided SF speech recognition assessment - CNC words presented at 65 dB SPL from a speaker located at 0 degrees azimuth and 1 meter from the patient Adaptive speech in noise sentence test aided and unaided (QuickSIN, BKB-SIN) at 65 dBA - signal routed to a speaker placed at 0◦ and 1 meter from the patient and the noise at 90 ◦ or 180 ◦ behind the patient

Question 46

What listening tests should be done in the sound field for those with single-sided deafness?

Answer 46

Unaided and aided SF warbled tone detection thresholds (determines functional gain) - done btw 0.5-6 kHz Adaptive speech in noise sentence test aided and unaided (QuickSIN, BKB-SIN) at 65 dBA - position the patient so one speaker is at 90◦ and the other at 270◦ and route speech signal to the speaker adjacent to the poorer ear and the competing noise to the better ear *Improved SNR between aided and unaided conditions predicts bone conduction device benefit for SSD in noise

Question 47

What should the pre-op counseling session for a bone-anchored hearing device include?

Answer 47

The potential benefits of implantable BCDs relative to the recipient’s needs (comparison of aided vs unaided) The expected improvement in sound quality a patient can receive with a surgical bone conduction solution compared to a demonstration with a non-surgical solution (preoperative demo vs. postoperative performance) The intervention process including the surgical procedure, the time required for healing, activation of the sound processor, and aftercare Cost and payment logistics

Question 48

What codes should you use for bone-anchored devices?

Answer 48

92626 - eval of auditory function for surgically implanted device(s) candidacy or post-op status of surgically implanted device(s); first hour 92627 - eval of auditory function for surgically implanted device(s) candidacy or post-op status of surgically implanted device(s); each additional 15 minutes 92622 - diagnostic analysis, programming, and verification of an auditory osseointegrated sound processor; first hour 92623 - diagnostic analysis, programming, and verification of an auditory osseointegrated sound processor; each additional 15 minutes

Question 49

What are the rules about billing and coding?

Answer 49

You cannot report 92622 and 92623 in conjunction with 92626 and 92627

Question 50

What are the 4 major bone conduction implant devices?

Answer 50

Cochlear BAHA Oticon Pronto MED-EL Bonebridge Medtronic Sophono

Question 51

Are their two types of osseointegrated implants for the Cochlear BAHA?

Answer 51

Yes Percutaneous BAHA Connect Transcutaneous BAHA Attract

Question 52

What features are present in the new implant for the BAHA Connect? (the screw - BI300)

Answer 52

A wide diameter of 4.5 mm for enhanced stability with the skull Two length options (3 and 4 mm) and smaller threads to improve load distribution and bone contact (everyone's skulls are different in thickness) Surface of the fixture is designed to facilitate rapid osseointegration by allowing osteoblasts and supporting connective tissue to migrate into the small gaps in the roughened surface

Question 53

What features are present in the new abutment for the BAHA Connect?

Answer 53

Five different lengths (6, 8, 10, 12, and 14 mm) Hydroxyapatite coating to promote skin integration by enhancing epithelial cell binding compared to plain titanium surfaces

Question 54

Has the BAHA Connect been FDA-approved?

Answer 54

Yes It has an MRI compatibility of up to 3 tesla The FDA has approved a 12-week gap between implantation and connection (activation within 4-6 weeks is feasible due to design improvement that promote rapid osteointegration with minimal complications)

Question 55

How does the BAHA Attract work?

Answer 55

Coupled to bone with a BI300 fixture After the BI300 is implanted securely into the skull, the surgeon may connect the implant magnet to the fixture with a cover screw

Question 56

Is the BAHA Attract FDA-approved?

Answer 56

Yes The Baha Attract has an FDA-approved MRI compatibility of up to 1.5 tesla The FDA has approved guidelines that state that four weeks should pass between implantation of the Baha Attract and the fitting of a Cochlear Baha sound processor with an external magnet

Question 57

Are there multiple different types of BAHA sound processors?

Answer 57

Yes The Cochlear Baha 5 the Cochlear Baha 5 Power the Cochlear Baha 5 SuperPower The Cochlear Baha 6 Max *Fitting ranges are different for each one

Question 58

What is the Cochlear Osia?

Answer 58

Introduced in the US in 2019 Indicated for patients with CHL, mixed HL with BC PTA thresholds of 55 dB HL or better, and SSD Approved for children 5 years and older Uses the BI300 osseointegrated implant Uses piezoelectric transducer which undergoes mechanical deformation when an electric voltage is applied

Question 59

What are the benefits for the Osia system?

Answer 59

Piezo transducer has no movement between parts that can cause wear over time (it is implanted under the skin) - active transducer Provides excellent hearing performance in noisy environments and enhances that clarity of high frequency speech (no skin attenuation) Sound processor is slim, smart, and robust, featuring wireless connectivity Provides powerful and consistent performance over time

Question 60

Can the Cochlear Osia go into an MRI?

Answer 60

Yes, up to 3.0 tesla

Question 61

What is the Oticon Pronto implant system?

Answer 61

4.5 mm wide diameter and is available in lengths 3 and 4 mm OptiGrip technology to provide a larger surface area for bone adherence, enhancing stability, and facilitating quicker osseointegration

Question 62

What are the features of the Pronto 5 sound processor?

Answer 62

Has all features of an advanced hearing aid, including program selection, temper-proof battery, volume control, low-battery warning system, and inlet for programming Premium 360 degree sound Feedback prevention Smallest bone conduction devices with two power levels Connectivity Soft band option

Question 63

What is the MED-EL bonebridge?

Answer 63

An active bone conduction device, transcutaneous (uses magnets) Uses electromagnetic transducer, anchored directly to the bone (direct drive) Uses wireless signal transmission between the SAMBA 2 audio processor and the active implant Intact skin, no pressure, all day comfort Two small screws to fix device to bone

Question 64

How does the SAMBA/bonebridge work?

Answer 64

The SAMBA sound processor attaches to the head via a magnet The processed signal is then delivered to a transmitting coil located at the periphery of the SAMBA. The transmitting coil converts the signal to an electromagnetic signal that is transmitted across the skin and received by the internal coil of the BONEBRIDGE implant

Question 65

What are the 4 components of the internal implant?

Answer 65

A coil to receive electromagnetic signals from the external sound processor A magnet, encased in silicone sleeve, located at the center of the coil A processor, enclosed in a titanium case, that analyzes signals and determines the appropriate stimulation for the recipient A bone conduction floating mass transducer that converts signals from the processor into mechanical oscillations delivered to the skull

Question 66

What is Adhear?

Answer 66

Non-surgical bone conduction device that does not exert any pressure on the skin - from MED-EL Contains an adhesive adapter, which is a soft pad with a sticky surface that is placed on the hairless area just behind the auricle The adhesive adapter contains a plastic connector that is used to couple to the sound processor and the deliver mechanical oscillations to the mastoid bone Contains a snap coupler that is coupled to the connector of the adhesive adapter Directional and omni-directional microphones that automatically adapt to the user’s environment, built-in noise reduction and feedback cancellation Studies show substantial hearing improvement in both children and adults, with children experiencing average PTA4 gains exceeding 30 dB and adults achieving gains exceeding 18 dB

Question 67

What is the Medtronic Sophono implant?

Answer 67

Contains two samarium cobalt magnets enclosed in a titanium case and is designed to be implanted in a single-stage procedure A transcutaneous device, FDA approved for activation one month after surgery Approved by the FDA for MRI up to 3.0 tesla

Question 68

What is the latest sound processor for the Medtronic Sophono implant?

Answer 68

Medtronic Alpha 2 MPO ePlus For individuals with CHL/MHL with BC average (0.5,1,2, and 3 kHz) of up to 45 dB HL and for those with SSD with normal hearing in the opposite side (≤20 dB). Up to 45 dB of gain (for the 60 dB SPL input) and a peak output force level of 121 dB SPL 6 dB of greater gain with the Medtronic Alpha 2 MPO ePlus relative to competitive transcutaneous bone conduction implant systems (Kohan, 2015) Lithium ion rechargeable battery

Question 69

Are there other non-surgical options?

Answer 69

Yes Generally apply steady pressure to the mastoid cortex via an elastic band or eyeglasses Limited by soft tissue attenuation and chronic pressure from the device, making them suitable for a patient prior to surgical implantation, young children with conductive or mixed hearing loss, patients who are not surgical candidates with conductive or mixed hearing loss