Performance testLecture 12 10/03/2015

The child is conditioned to wait for a frequency specific stimuli in the sound field and respond using a play activity

used from developmental age of 30 months [often as precursor to PTA since both use play technique]

Performance test

Should be quiet Should be free from distractions Should be comfortable Should be large enough to accommodate

parent, child, tester and equipment

Test room

Test set up

P TC

TSLM

low table

loudspeaker

VISUAL+AUDITORY RESPONSE REWARD

Initially hold and guide child’s hand◦ removes need for verbal feedback ◦ this guides response promptly◦ avoids premature response

Progress to gentle restraint

Conditioning

Within 6-12 attempts, the child should sit and wait with only occasional correction needed◦vary interval to ensure child is waiting

reliably◦correct any wrong response immediately◦make sure stimulus is supra-threshold

Reward with enthusiastic verbal and social praise

Proceed until child responds to the auditory signal alone

Conditioning

AUDITORY RESPONSE REWARD

Typical test sequence would be to gather minimum responses at high, low and mid frequencies [with stimuli all on one side]

Commence supra-threshold and decrease until minimum level with 2 out of 3 responses [aim to get to 25 dB HL]

Testing

“Go” and “sss” - 1m away and completely out of child’s vision

Hand held warblers (FMT)- out of the child’s vision and suitable distance away

Warble (FM) tones from a loudspeaker - 1m in front of child

Stimuli and placement

Balls on sticks Men in boat Pegs in board Stacking beakers Dropping bricks in box Knocking skittles off table** false responses should be correctable

Suitable activities

Measure voice levels on SLM and convert to dB(HL)

Measure levels on hand held warblers with SLM and convert to dB(HL)

Measure sound stimuli at the same distance that they were presented at

Calibration

◦Ensure you avoid visual cues◦Remember to reward◦Vary inter-stimulus interval◦Correct wrong response positively eg “let’s listen again” or “remember to

wait for the sound” Do not “tell the child off”, ◦Change ‘play’ activity to maintain

interest

Points to remember

◦Return to supra-threshold level if no response and when change frequency

◦Include localisation check at end of test◦Obtain minimal responses for 2-3

frequencies before attempting PTA◦Attempt to use 10 up 5 down procedure◦If conditioning not established after

about 15-20 presentations use VRA or distraction

Points to remember

Measured in dB(HL) Measures how many dB worse or better the

subject’s hearing is than normal human hearing

Results are recorded on an audiogram Air conduction is measured with

headphones Bone conduction is measured with the bone

vibrator Inserts may also be used

Pure Tone Audiometry

Audiometer and transducers must conform to standards

Audiometer should be calibrated at least every year

Carry out regular daily and weekly checks

Equipment

Wood S Chapter 6, in McCormick B [ed] Paediatric Audiology 0-5 years,. London: Whurr, 1993;155-186.

Key reading

Used from developmental age of 36 months Usually proceed to this after a successful

Performance Test Same set up as Performance Test but each

ear tested separately with audiometer placed directly behind child to avoid visual cues

Test room as for performance test ie quiet,comfortable, large no distractions

Pure Tone Audiometry with children

Test set up

parent

tester

child

audiometer

low table

Condition as for Performance Test by demonstration and also with verbal instructions

If there is suspicion of a severe hearing loss conditioning can be done with the bone conductor

Procedure - conditioning

Frequencies 0.5-4 kHz Test 1KHz in each ear first Test 4KHz and 500Hz in each ear Test 2KHz in each ear Use 10 down 5 up procedure as for adults R/L [beware of asymmetry]

Frequency and levels tested

May use 20 down, 10 up May not need to go below 15-20 dB HL Need to vary inter-stimulus interval – may

need to include occasional supra-threshold stimuli

Choose the next threshold on the basis that it may be the last!!!

What if child has poor concentration?

Air conduction or bone conduction first?

If sound field results show some hearing loss do bone conduction first

Why?

If sound field results are within normal limits do air conduction first

Why?

If the child is clingy or anxious start with the performance test

The headphone can be detached from the band and held to the ear at first

Try using the bone conductor first Tester or parent or sibling can wear the

headphones first Don’t choose activities with a fiddly

response Don’t ask, tell!

Tips

Child should be able to do unmasked PTA Use different play activity for pure tone and

masking noise [possible from around age 4-5 yrs]

Avoid switching task too much Describe masking as rushing noise pure

tones as a whistle Select thresholds to be masked carefully –

may not be able to do all frequencies Beware of high levels of masking

Masking

3.5% Caused by pressure from transducer on

pinna Overcome problem by using insert ear

phones or place an admittance tip in the ear canal

Collapse of ear canal

Subject to more variation than a-c Limited output level Children with otitis media can show

depressed b-c thresholds at high frequencies, with subsequent improvement when the condition resolves

Bone conduction thresholds

Vibrotactile thresholds(source: Boothroyd and Cawkwell,1970)

Frequency(kHz)

0.25 0.5 1

a-c 80-110 100-120 120-130

b-c 20-40 55-70 80-85