Audiology Refresher 3
Presented in February, 2004
Behavioural Observation Audiometry
The high amplitude sucking paradigm
The HAS technique makes use of three characteristics of babies.
- Babies like to listen to sounds.
- Babies lose interest in a sound when it is presented repeatedly.
- Babies who have lost interest in a repeated sound will become interested if a new sound is presented.
The baby’s interest in sound is measured by their rate of sucking. When a new sound is presented the baby sucks more rapidly. This technique is useful with babies up to 4 months old.
The head-turn procedureThis technique makes use of the fact that babies are interested in moving objects. It’s typically used with older babies from about 5 months.
|Stirs from sleep|
|Age||Noisemakers (Approx dB SPL)||Warbled pure tones (dB HL)||Speech (db HL)||Expected response||Startle to speech (dB HL)|
|0-6 wk||50-70||75||40-60||Eye-widening, blink, stirring or arousal from sleep, startle||65|
|6 wk-4 mo||50-60||70||45||eye-widening, eye-shift, blink, queiting; beginning rudimentary head-turn by 4 mo||65|
|4-7 mo||40-50||50||20||head-turn on lateral plane toward sound; listening attitude||65|
|7-9 mo||30-40||45||15||direct localisation of sounds to side, indirectly below ear level||65|
|9-13 mo||25-35||38||10||direct localisation of sounds to side, directly below ear level, indirectly above ear level||65|
|13-16 mo||25-30||30||5||direct localisation of sound on side, above and below||65|
|16-21 mo||25||25||5||direct localisation of sound on side, above and below||65|
|21-24 mo||25||25||5||direct localisation of sound on side, above and below||65|
* testing done in a sound room. (Modified with permission from F McConnell and P H Ward: Deafness in Childhood, Nashville, Tennessee, Vanderbilt University Press 1967.)