Bone Anchored Hearing Aids

Dr. Amir Soltani Clinical Audiologist

UBC Resident Otology Lecture Series BC Children Hospital

Sep 13, 2013

BAHA www.dramirsoltani.com/links/baha What is the BAHA system

A well recognized hearing treatment for

conductive and mixed hearing losses since 1977 ,As well as SSD

The BAHA system is composed of three parts: a titanium implant, an external abutment and a sound processor

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In the early 1960s it has discovered that titanium provides an excellent material for implantable devices. Titanium is accepted by the human body and forms a bond with surrounding bone.

This is a process termed “osseointegration,” which takes place as the titanium implant integrates and forms a permanent structure with the living bone. The process of bone osseointegration is also the foundation for dental implants..

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How does the BAHA system work for Mixed and Conductive Hearing Loss?

BAHA A sound processor picks up sound vibrations. An abutment is attached to the sound processor and the implant.

The abutment transfers the sound vibrations from the processor to the implant.

Titanium implant is placed in the mastoid process, where it fuses with the living bone (osseointegration). The implant transfers the sound vibrations to the functioning cochlea.

This creates direct (percutaneous) bone conduction. In contrast, traditional BC hearing aids connect indirectly to the bone through unbroken skin (transcutaneous) and work by exerting pressure against the skull.

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Types of hearing loss the BAHA system can help

Mixed and Conductive hearing loss – unilateral or bilateral fitting – Due to examples such as: Chronic otitis media Congenital atresia Cholesteatoma Middle ear dysfunction/disease External otitis

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The Baha Sound Processor snaps on to the abutment. The processor is small, discreet and is available in a variety of colors. The volume controls are conveniently located for easy adjustments.

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BAHA Candidate Mixed and Conductive Hearing Loss

> 5 years of age < 45 dB HL BC PTA > or equal to 60%

speech discrimination scores Symmetric bone conduction thresholds are

defined as less than 10 dB difference in average or less than 15 dB at individual frequencies (0.5, 1, 2, and 4Khz)

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Bilateral Conductive Hearing Loss

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Biateral mixed hearing loss

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Severe Mixed or Sensorineural Hearing Loss

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Unilateral Conductive Hearing Loss Canal Atresea

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Audiological Assessments:

1: Pure tone Audiometry, including AC&BC testing

2: Speech tests through insert receiver or headphones + Bone vibrator testing

A: SRT B: SDS C: Quick SIN

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Impedance testing includling: (If possible)

Conventional (low probe tone) tympanometry and high probe tone if necessary

Acoustic reflex thresholds, Ipsi & Contra Lateral stimuli

OAE

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Test Rod The test rod is used as a pre-operative

device. It is particularly useful for potential candidates who are on the limits of the audiological criteria or if there is uncertainty as to which side to place the implant. The test rod can also be used to demonstrate the abutment, snap coupling and sound processor.

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Counseling 1: Introduction ( How it works) 2: Benefit – Limitation 3: Documentation & Pre-post fitting

assessments Questionnaire (Cosi-Aphab) 4: Realistic expectation

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Sound processors from Cochlear 1: BAHA 3 2: BP 100 & BP 110 3: BAHA Intenseo 4: BAHA Davino 5: BAHA Compact 6: Classic 300 7: Cordell

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Oticon product 1: Ponto 2:Ponto pro **Programmable, under Noah, 4 memory,

10 band frequency shaping, adaptive multi directional mic, data logging

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Direct bone conduction Summary: Works independently of ear canal and

middle ear Direct transmission gives clear sound Preoperative testing possible High wearing comfort Safe and simple surgery

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Advantages of the BAHA system in comparison to other alternatives Mixed and Conductive Hearing Loss

Over bone conduction devices More comfortable Better sound quality Aesthetic appearance

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Over air conduction devices

No occlusion of the ear canal No feedback problems Sound bypasses the middle ear

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Over reconstructive surgery

Predictable results Low risk for the patient Reversible surgery

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Disadvantages of other devices Mixed and Conductive Hearing Loss

Bone conduction devices Discomfort Poor sound quality Cumbersome

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Air conduction devices

Presence of ear mould aggravates infection

Acoustic feedback Dependent on middle ear function

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Reconstructive surgery

Potential risk of hearing damage Less predictable outcome

BAHA FDA Clearances

1996 – 2002

1996 – the BAHA system was cleared to treat mixed and conductive hearing

loss. 1999

– the BAHA system was cleared for pediatric use in children age five and older.

2001 – the BAHA system was cleared for bilateral fittings.

2002 – the BAHA system was cleared for use in patients with unilateral

sensorineural hearing loss also known as Single Sided Deafness (SSD).

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Clinical Aspects Single Sided Deafness

For adults: – Difficulties to understand in group conversations, or

with noise. – Difficulties to localize sounds, – Difficulties to understand a person situated on the

deaf side.

For children: – - School handicap.

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Unilateral sensori-neural hearing loss Single Sided Deafness SSD

Acoustic neuroma tumors Sudden deafness Neurological degenerative disease Genetics

Ototoxic treatments Inner ear malformation Trauma

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Options available 1: BAHA, Implanted in the mastoid of poorer

ear, transcranial routine of signal 2: Transcranial CROS, BTE or ITE power aid

fitted to the poorer ear 3: Trans Ear, Quasi BC fitted to the poorer ear 4: Wireless CROS(Phonak, Unitron) 5: Wired CROS

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BAHA Candidate Single Sided Deafness

> 5years of age Intended to improve speech recognition Intended for patients with SSD or unilateral sensori-

neural hearing loss when the other ear is normal Normal hearing is defined as PTA AC threshold equal to

or better than 20 dB at .5, 1, 2 and 3kHz For patients who cannot or will not use AC CROS HA Functions by transcranial routing of the signal

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How does the BAHA system work for SSD?

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Advantages of the BAHA system in comparison to other alternatives Single Sided Deafness

Effective approach in patients with unilateral deafness Alleviates the degree of hearing handicap resulting from

the head shadow effect Improves speech intelligibility in noise Improves the patient’s quality of life Provided a greater perceived benefit compared to CROS

system

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Head-shadow Effect Review

Minimal effect at 1500Hz, but continues upward to approximately 15 dB at 5000 Hz (Staab 1988b)

For speech the overall reduction of effective intensity is approximately 6 dB (Tillman et.al., 1963)

Its effect on speech intelligibility is approximately a reduction of 23% when sound is coming directly from the ‘bad’ ear side.

Binaural amplification in eliminating the head shadow effect can be about 25% or 6 dB improvement in the S/N ratio (from the Handbook of Clinical Audiology, Katz)

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Conclusion Why BAHA for Single Sided Deafness

Effective approach in patients with unilateral deafness

Alleviates the degree of hearing handicap resulting from the head shadow effect

Improves speech intelligibility in noise Improves the patient’s quality of life Provided a greater perceived benefit compared

to CROS system