What is the prevalence of HL in babies?
1-2 / 1000 children born with moderate + hearing loss (about 1100-1200 in Canada each year – Hyde, 2005)
Untreated loss can cause: (4)
poor academic achievement
language difficulties
behavioural/social problems
low self-esteem
Before newborn hearing screening:
children with severe-profound finished high school with grade 3-4 reading level, language abilities of 9-10 year old
When hearing loss is identified and treated early in infants: (2)
- speech and language - similar to hearing peers
better emotional and social development
At what age should infants be screened and evaluated? (3)
- all infants should be screened within 1 month
- full audiologic/medical evaluation by 3 months
- all infants with HL should have intervention by 6 months
Principles of Joint Committee on Infant Hearing: (5)
- Family-centered (information, privacy, decisions)
- Immediate access to technology when needed
- Continual monitoring when needed
- interdisciplinary intervention programs w/ experts
- Measure outcomes and evaluate effectiveness of services
What are the two approaches to screen infants?
- Otoacoustic emissions
TEOAE or DPOAE
very efficient (like a tympanometric test) - Automated auditory brainstem response
slightly more time to conduct
requires more expertise
assesses more of the auditory system
What are characteristics of Automated auditory brainstem response? (3)
- Slightly more time to conduct
- Requires more expertise
- assesses more of the auditory system
What is the Hit rate?
Sensitivity - Proportion of hits, given disease or condition
Test Decisions and the Receiver Operating Characteristic
ROC curve depending on the strength of OAEs of infants from the receivers
Overlap between distributions,
A good test will distinguish the two distribution between hit rates and false alarms
What do these graphs represent?
Screening Performance of ABR vs OAE HIT vs False alarms rates
Why is it important to have early access to hearing for a child?
Early access to hearing is valuable—and not just for language! e.g., localization, music etc.
What are two types of assessments?
Behavioral
Physiologic
What 5 behavioral assesment techniques in audiology?
- Behavioral observation audiometry
- Visual reinforcement audiometry
- Conditioned play audiometry
- Speech audiometry
- Standard audiometry
What 3 Physiologic assessment techniques in audiology?
- Immittance testing
- Otoacoustic emissions (primarily screening)
- Electrophysiological audiometry
What is the cross-check principle in pediatric audiology?
Diagnosis NOT based on one test – two or more tests must agree
Would one hearing assessment be enough?
- Hearing assessments may require multiple sessions, with multiple testers
*Results will often be inconclusive
* Minimal response is not threshold
In auditory development on average at 0-4 months in infant will:
startle, blink in response to loud sounds (e.g. 80 dB)
In auditory development on average at 4-7 months in infant will:
head turn toward sounds
In auditory development on average at 7-24 months in infant will:
head turn at soft levels, approaching threshold
In auditory development on average at 24 months in infant will:
possible to engage children in play
If children are really small (6 months), which technique is useful in screening?
Behavioural Observation (BO)
- Unconditioned responses
sudden/novel sounds are presented
observe baby’s response to sound
response = heard
no response = not heard
important to pay attention to level, distance, and possible visual cues as well as parent movement
What does the baby have to do to show a response to sounds?
increase/decrease in activity
onset/offset crying
change in breathing rate
vocalizations
eye widening, brow furrowing or expectant look
smiling
head turning (in older infants)
blinks
jerks
ANYTHING!
If children are really small (6 months up to 24/30 months), which technique is useful in screening?
Visual Reinforcement Audiometry (VRA):
- conditioned response
- two testers
loud sound with dancing creature
once head turn is established, reduce sound levels, but might not turn because bored - child must be able to turn head
- parent must do nothing!!
