Download Bone conduction BOA

Berlin, 17-06-2016
BONE CONDUCTION BOA
WHY AND WHEN?
Kristin Kerkhofs
Audiologist & Lecturer
Berlin, 17-06-2016
BOA?
• Behavioural Observation Audiometry
“Observation of an unconditioned response to acoustic
stimuli at the age of 0-6 months”
• Behavioural observation ?
Berlin, 17-06-2016
Paediatric Audiology Team - Flanders , Belgium since 2001
Bruges
Ostend
Ghent
Deinze
Courtrai
Antwerp
Hasselt
Brussels
Berlin, 17-06-2016
Our mother of pediatric audiology…
Marion Downs
1914-2014
Berlin, 17-06-2016
Monique Delaroche (Bordeaux)
Rehabilitation centre
1992
I
1998
I
2002
I
UEHS Kind & Gezin (Child & Family)
2016
I
Berlin, 17-06-2016
SCREENING IN FLANDERS (northern part of
Belgium) by Kind & Gezin (Child and Family)
• Community based UEHS since 1998
• Screening by a K&G nurse under the age of 4 weeks (at home
or at the regional house)
• 2 steps protocol: AABR/AABR until 2013 – since 2013 SSEP/SSEP
• Referral to specialised center for audiological/medical
assessment, early home guidance, rehabilitation
• Since 1998 : 1 072 586 screened newborns
• Target cover: >98%
Berlin, 17-06-2016
Audiological assessment after screening
OBJECTIVE
HF Tympanometry
Otoacoustic Emissions
(TEOAE or DPOAE)
ABR and ASSR
SUBJECTIVE
Behavioral Observation
Audiometry (BOA)
Bone conduction
Insert earphones
Berlin, 17-06-2016
Berlin, 17-06-2016
Why Behavioural Observation Audiometry?
• Cross-check principle:
‘The cross-check Principle in Pediatric Audiometry’. 1976
J.F. Jerger & D. Hayes (Archives of Otolaryngology)
• Special cases:
ANSD
• In deaf children responses can be measured at a
high level when performed at a very young age
Berlin, 17-06-2016
Why BOA with bone conduction?
• Response of the best inner ear
• More reactive responses
• Presence air-bone gap
• Prevalence of middle ear problems such as OME
• Special cases
• ANSD
• Unexpected permanent conductive hearing loss
(example: incudostapedial disconnection)
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Prevalence of Temporary Conductive HL
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Purpose of BOA
• BOA’s purpose is to obtain air and bone conduction data as
close as possible to the hearing threshold for a broader
frequency range of at least 500 - 4000 Hz.
• This can only be performed in optimal test conditions and by
following a strict protocol and has to be done by experienced
pediatric audiologists (preferably with 2 audiologists)
• Best age: before 3 months
Berlin, 17-06-2016
Setup
Optimal test conditions
• light sleep
• during feeding or while sucking
• check whether the child is in a deep sleep!
Transducers
• BC: diadem or softband with vibrator (different sizes!)
• AC: insert earphones with foamtip or earmold
Stimulus
• Warble or Freshnoise
Berlin, 17-06-2016
Procedure
• To obtain the minimal response level of the child it is necessary
to start below the expected threshold. A proper reaction can
only be obtained when reaching the minimal response level for
the first time for each frequency.
• Start with bone conduction at 30dBHL
• Continue with air conduction (insert earphones) and use the
measured threshold from BC or use information from ABR
• Minimize cue signals
• Increasing stimulus level
• Variate stimuli & ear
Berlin, 17-06-2016
Response behavior
•
•
•
•
•
•
•
•
•
opening eyes
moving eyelashes
eye widening
frowning
start or stop sucking
eye blink
decreased motion
increased motion
…
! The number of observable responses
is limited
Berlin, 17-06-2016
Minimal response level (MRL) with Behavioral
Observation Audiometry (BOA)?
Our findings in …
• normal hearing babies
• hearing impaired babies
 mild-moderate
 severe-profound
Berlin, 17-06-2016
MRL with bone conduction obtained through BOA with
normal hearing babies aged 4 to 8 weeks (after AABR-PASS)
[De Poolster, 2004]
Berlin, 17-06-2016
MRL with insert phones obtained through BOA with normal
hearing babies aged 4 to 8 weeks (after AABR-PASS)
[De Poolster, 2004]
Berlin, 17-06-2016
MRL in hearing impaired babies?
- Mild to moderate hearing loss
- Severe to profound hearing loss
• Monique Delaroche
“Is behavioral audiometry achievable in infants younger than 6 months of
age?” (2011)
• Jane Madell
"Pediatric Audiology“ (2008)
• future study
Berlin, 17-06-2016
Example of similarity between the MRL obtained through BOA,
VRA and CPA of a hearing impaired infant (De Poolster)
1. BOA 3m
2. VRA 7m
3. CPA 2jr
1
2
3
2
3
1
3
1
2
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Video BC BOA
Berlin, 17-06-2016
Case 1: temporary conductive HL
BOA at age of 2 weeks
• HF TYMP abnormale
• OAE absent
BOA at age of 4 weeks
• HF TYMP = normale
• OAE present
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Case 2: mild hearing loss
BOA 2m
•
•
•
VRA 6m
TYMP: normal
OAE: absent
ABR: 50dBnHL
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Case 3: ANSD (auditory neuropathy spectrum disorder)
BOA at the age of 2 month
TYMP: normal
OAE: present
ABR: no response
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BONE CONDUCTION BOA
WHY?
TYMP
ABR
OAE
SSEP
BOA is an essential part of the puzzle...
Berlin, 17-06-2016
But...
• can only be performed by experienced pediatric audiologists
• is a time consuming examination
• demands a lot of patience! (from examiner and parents)
Berlin, 17-06-2016
BONE CONDUCTION BOA
WHEN?
ALWAYS!
Berlin, 17-06-2016
More information?
www.biap.org
Berlin, 17-06-2016
Thanks for
your attention!