Lecture 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]

 Should be quiet  Should be free from distractions  Should be comfortable  Should be large enough to accommodate parent, child, tester and equipment

P T C T SLM 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

 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

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]

 “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

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

 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

◦ 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

◦ 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 presentations use VRA or distraction

 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

 Audiometer and transducers must conform to standards  Audiometer should be calibrated at least every year  Carry out regular daily and weekly checks

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

 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

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

 Frequencies 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]

 May use 20 down, 10 up  May not need to go below 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!!!

 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!

 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

 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

 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

Frequency (kHz) a-c b-c