11Paediatric behavioural audiometry
A baby cannot raise a hand to a tone, so paediatric audiometry is the art of reading what a child can do at each stage of development and building a valid threshold out of it. The youngest are merely watched for a flicker of response; a little older, they can be conditioned to turn toward a reward; older still, they will drop a block in a bucket each time they hear a sound. Choosing the right method by developmental — not chronological — age is half the skill; the other half is knowing what the result actually means, because an infant's response level overstates true threshold and the simplest method reveals only that a child reacted, never how softly they can hear. And throughout, the cross-check with objective tests is what keeps a charming but unreliable behavioural result from misleading the team. This module covers testing the very young.
FTMethod follows developmental age
The method is chosen by developmental, not chronological, age: BOA in the youngest, VRA from ~5–6 months, conditioned play audiometry from ~2–2.5 years, and conventional hand-raise audiometry from ~5 years.
CBOA — responsiveness, never threshold
Behavioural observation audiometry watches unconditioned changes (stilling, eye-widening, sucking). It measures auditory responsiveness only — NEVER threshold, habituates quickly, and must never be used to set hearing-aid gain. Treating a BOA “level” as a threshold is a classic and consequential error.
CVRA & conditioned play
Visual reinforcement audiometry conditions a head-turn rewarded by an animated toy or video and can yield true ear- and frequency-specific thresholds (children with hearing loss may not participate until 8–10 months). Conditioned play audiometry succeeds in over 95% of children aged 3+, and a trained test assistant markedly improves success at both.[2006]
CMinimal response levels & ear-specific testing
Infants respond at suprathreshold minimal response levels — a 6-month-old with normal hearing typically responds at 20–25 dB though true threshold is near 0 — so results are read against age norms. Insert earphones with pulsed/warbled tones give ear- and frequency-specific thresholds (125–8000 Hz) plus bone conduction; narrowband noise is for masking, not threshold.
CThe paediatric cross-check
The cross-check is paramount: a discrepancy such as a moderate ABR but a “severe-range” BOA is resolved by recognising suprathreshold responding, and a child profoundly deaf on evoked potentials should not startle to 75 dB speech. The principle that opened the chapter does its most important work here, where behaviour is least reliable.[1976]
Why is this inappropriate?
What does behavioural observation audiometry (BOA) measure?
From roughly what developmental age can visual reinforcement audiometry (VRA) give true thresholds?