Session 2: Behavioural testing Flashcards
what is the difference between behavioral and objective testing and are they used in isolation?
behavioural testing= expecting the child to respond to a sound.
Objective testing: child does not need to respond for a response to be recorded.
- the best test battery approach is to use them together
what is the purpose of behavioural assessment?
*sound detection:
- awareness, presence or absence of sound
- stimuli include warble tone, BNB, pure tones, speech sounds.
*Sound discrimination:
- ability to distinguish between sounds.
- often involve speech sounds
- sound identification: requires memory, not necessarily understanding
- require matching sounds to animals
- speech audiometry
*sound comprehension: Understand the meaning of sound
- involve speech tests
why is knowing the purpose of the behavioural assessment important?
depending on what the appointment s for, you will have different approaches: are you screening for a HL?
are you diagnosing a HL?
are you assessing the impact of HL?
are you testing a child with confirming PCHI?- for this child you wont just be screening thresholds, you’re going to need to get an accurate threshold, making sure you have all the freqs BC, AC etc
what is the purpose of screening for HL in behavioural assessment?
- To identify hearing loss early.
- Commonly uses school screening with pure tone audiometry.
What is the purpose of diagnosing hearing loss in behavioural assessment?
- To identify sensorineural hearing loss (SNHL) cases not detected by the newborn hearing screen.
- To detect children with severe otitis media with effusion (OME).
What is the purpose of assessing the impact of hearing loss in behavioural assessment?
- To determine the need for intervention.
- To evaluate and assess the benefit of intervention.
What is the purpose of behavioural assessment for infants/children with confirmed PCHI (Permanent Childhood Hearing Impairment)?
- To accurately fit hearing aids.
- To monitor hearing levels over time.
- To assess suitability for cochlear implants.
should we be practicing BOA?
no, Behavioral observational audiometry is under review so it is not in practice but just be aware of it
name some behavioural audiological assessments techniques with reinforcements and without reinforcements
*techniques without reinforcement:
- Behavioural observational audiometry (BOA)
- Distraction testing (DT)
*techniques with reinforcement:
- Visual reinforcement audiometry (VRA)
- Play audiometry
what are the different developmental ages or each of the behavioural tests and why?
BOA= 0-6 months
DT= 6/7- 12 months because they develop object permanence so it wont work beyond this
VRA= 6-24 months because they get head control so it works
Play Audiometry= 2-5 years because they can follow simple instructions
Pure Tone Audiometry= >5 years
*it might be that you still need to adapt
what is sound field audiometry?
sound field audiometry is a procedure to assess the hearing sensitivity of a person in which acoustic signals are presented through one or more sound sources in a room (i.e. not earphones)
what are some limitations with sound field testing?
- ensuring that the level of signals at the 2 ears is what is intended
- remember the threshold in sound field testing only refer to the better hearing ear = so don’t discharge based on this as you could be missing a unilateral HL
KNOW YOUR DISCHARE CRITERIA
SO THE LIMITATIONS ARE:
- As the sounds are coming from a speaker it only tests the better hearing ear, the loss could be unilateral or
bilateral (2 marks).
- Doesn’t give information if the hearing loss is conductive or SNHL (2 marks)
Why is ear-specific information preferable in audiometry?
Ear-specific information is preferable as it allows for precise assessment of each ear’s hearing sensitivity. However, it is not always possible to obtain such information in sound field audiometry.
What are the two main uses of sound field audiometry? explain fully use, who its performed on?
- Unaided testing: Evaluates a person’s natural hearing sensitivity without the use of hearing aids or other amplification devices.
- This provides a baseline.
- Its mainly performed on young children who are unable to comply with individual ear testing using earphones or inserts.
- Aided testing: Assesses effectiveness of hearing aids, CIs, or other assistive devices in use.
- It measures the minimal response levels to determine the functional performance of the device.
- Performed on children of all ages who are using HA or CI
what are the 2 systems used for testing children in the sound field?
1- Hand- held Audiometry:
- A portable device used for informal or quick assessments, such as in schools or home settings.
2- Static Speaker System:
- A fixed system with calibrated speakers placed strategically in a room, commonly used in clinical settings for consistent and accurate sound presentation.
What is the purpose of aided testing in sound field audiometry?
- Functional Aided Gain: Provides a basic demonstration of how much a hearing aid or device improves hearing.
- Hearing Aid Adjustment: Checks how well the device is working and helps audiologists make necessary adjustments to improve its performance.
what are the types of sound field?
- Free sound field
- Diffuse sound field
- Quasi-free sound field
What is a Free Sound Field?
- What it is: A room where sound waves are not affected by the walls, ceiling, or floor.
- Example: Happens in a special room called an anechoic room that absorbs all sound reflections.
- Reality: Rarely used in clinics because these rooms are expensive and difficult to build.
What is a Diffuse Sound Field?
- What it is: A room where sound waves bounce off the walls, ceiling, and floor a lot, creating many echoes.
- Example: A very echoey room, like a large empty hall.
- Reality: Not used in clinics because it doesn’t give accurate results for hearing tests.
What is a Quasi-Free Sound Field?
- What it is: A room where sound waves are slightly affected by the walls, ceiling, and floor.
- Example: A normal clinic room where there are some echoes, but not too many.
- Reality: This is the most common type of sound field used in hearing tests because it is practical and reflects real-world listening conditions.
What are the requirements for the loudspeaker?
- The loudspeaker must be placed at head height of the seated listener.
- It should be directed towards the reference point.
- The distance from the loudspeaker to the reference point must be a minimum of 1 metre.
Where should the loudspeaker be placed?
- At head height of the seated listener.
- Directed towards the reference point (where the listener’s head would be).
What is the required distance between the loudspeaker and the reference point?
A minimum of 1 metre.
What are the SPL (Sound Pressure Level) requirements around the reference point without the test subject and chair?
- 15 cm above, below, left, and right of the reference point: SPL should not deviate by more than 2 dB.
- 10 cm in front and behind the reference point: SPL should not vary by more than 1 dB.
What types of test signals are specified for sound field testing?
- Frequency modulated tones (warble tones): Used because they reduce issues caused by echoes.
- Narrow band noise (NBN): Provides frequency-specific stimuli for testing.
Why should pure tones only be used in anechoic rooms with sound field testing?
- Pure tones can cause standing waves (areas where sound cancels out or amplifies), which distort results in regular rooms.
- Anechoic rooms are free of echoes, making pure tones suitable for testing.
What are RETSPLs?
- RETSPLs (Reference Equivalent Threshold Sound Pressure Levels) are standardized reference values used to calibrate audiometric equipment.
- They represent the minimum sound pressure level (in decibels, dB) that an average person with normal hearing can detect under specific conditions.
Why are RETSPLs important for calibration?
RETSPLs provide a universal standard so that results are comparable, whether testing is done in the UK, USA, or any other country.
What are the reference thresholds in ISO 389-7 used for?
- They are used to measure how soft a sound can be for someone with normal hearing to detect it.
*This includes:
- Pure tones heard with both ears in an open space (free-field) while facing the sound source.
- Noise bands heard with both ears in a room where sound reflects off walls evenly (diffuse sound field).
What are correction factors, and why are they important?
- Correction factors are adjustments provided by ISO 8253-2.
- They account for the increase in sound pressure at the ear closest to the loudspeaker when sound comes from 45° or 90° angles.
- This ensures test results remain accurate despite differences in sound intensity between ears.
which is more reliable: hand held generators or static speaker set up?
static speaker set up
Whats the role of hand held generators?
1- used for conditioning young children to respond to tonal or NBN prior to ear specific testing
2- used in distraction testing in community clinics where VRA facilities are not available
What is dB SPL (Sound Pressure Level)?
*What it is:
- dB SPL is referenced to a very low baseline of sound pressure: 20 micropascals.
- It measures the physical intensity of sound but doesn’t link to how humans perceive it.
*Usefulness:
- It’s useful for things like hearing aid prescription formulas but less helpful for everyday sound field measurements.
- Instead, REM (Real Ear Measurements) is preferred for fitting hearing aids.
*Takeaway:
- While dB SPL is scientifically precise, it doesn’t offer much advantage for clinical work compared to other methods.
What is dB HL (Hearing Level)?
*What it is:
- dB HL adjusts sound measurements to reflect normal human hearing thresholds, making it easier to understand hearing test results.
*Why it’s important:
- It’s the ideal standard for hearing tests with headphones or inserts.
- Tests in a quasi-free sound field (like a clinic room) are accurate if sound variation is small (less than 2 dB at all frequencies up to 4 kHz).
- Listening with both ears (binaural) is 2–3 dB more sensitive than listening with one ear (monaural).
*Correction Factors:
- These adjustments account for how the angle of sound (e.g., 45° or 90°) affects the louder ear.
What is dB(A)?
*What it is:
- A sound measurement based on the A-weighting scale, which mimics how the human ear hears different frequencies.
*Why it’s useful:
- It’s based on the 40-phon equal loudness curve, which reflects normal human hearing sensitivity at low sound levels.
- You can convert dB(A) to dB HL for clinical work when using natural or hand-held sound generators.
- The sound level meter (SLM) must be set to A-weighting for accurate results, and conversions are applied afterward.
How is sound measured in sound field testing for children?
- In sound field testing, sound is measured at certain distances using a sound level meter (SLM) set to dB(A).
- It is important to note that the sound level at the child’s ear may not be exactly the same due to variations in distance, positioning, and room acoustics.
- These slight variations are acceptable within the context of sound field testing.
what is the advantage of hand held generators?
- sound source closer to an ear can improve more significant
left/right differences (5-10dB) helping distinguish between which ear is responding, so is therefore and advantage of distraction testing
what are the 3 stages of calibration for sound field testing?
Stage A: routine examination and listening test.
- check connections, cables etc
- check audiometer output at ‘just audible’ levels for all appropriate signals.
- listen at higher output levels (60-70 dBHL) to check for distortion, function of interrupter switches etc.
- check of subject responses and monitor circuits
Stage B: periodic electroacoustic test (12 monthly)
- Does equipment meet standards of;
*frequencies and characteristics of FM tones
*Attenuator steps- linearity
* Harmonic distortion
- Every 3 months the SPL at the reference point should be checked and compared to relevant standards and adjustments made as appropriate.
- normally performed by the manufacturer
- this is one so output levels are adjusted so dial settings are achieved in a quansi- free sound field at the recommended distance.
Stage C: every 5 years.
- at the initial set up of a sound field system, the ambient noise level should be checked.
- the uniformity o the field around the reference point should be checked.
- the room reverberation time should also be checked
What is BOA?
(Behavioral Observation Audiometry) which is observing changes in a child’s behavioural in response to an auditory stimuli
