Nearly half of infants need more than one brainstem response test

Design

retrospective review with univariate and multivariable regression

Population

630 infants undergoing auditory brainstem response testing at a tertiary free-standing children's hospital, 2019 to 2024

Primary outcome

number of brainstem response tests needed for definitive diagnosis, and time to diagnosis and hearing aid fitting

Effect

55.6% diagnosed with one test, 29.7% needed two, 14.7% needed three or more; hearing aid fitting at 11.2 vs 5.9 months if diagnosed after vs by 3 months (P<0.001)

Early hearing detection depends on a definitive diagnosis by three months and amplification by six, and auditory brainstem response testing is the bottleneck. This retrospective review of 630 infants tested at a free-standing children's hospital between 2019 and 2024 asked how many tests it actually takes.

Of the 630, 579 (92%) reached a definitive diagnosis by brainstem response. Only 322 (55.6%) of those got there with a single test; 172 (29.7%) needed two and 85 (14.7%) needed three or more. The consequence is measurable downstream: infants diagnosed after three months of age were fitted with a hearing aid at a mean 11.2 months against 5.9 months for those diagnosed by three. Otolaryngology consultation was associated with diagnosis after three months on both univariate and multivariable analysis (adjusted hazard ratio 0.46, 95% CI 0.38 to 0.55) - almost certainly because complex cases get referred, not because the referral causes delay.

The barriers the authors identify are all operational rather than clinical: the infant's sleep state, coordination between providers, middle ear dysfunction, distance to the facility, and scheduling constraints. That is an unusually actionable list, because none of it requires new technology. Middle ear dysfunction in particular is worth pre-empting - a test abandoned because of an effusion is a test that has to be repeated, and screening for it before booking would remove a share of the repeats. Wherever brainstem response testing is centralised and families travel for it, every repeat test costs months.

• Assume nearly half of infants will need a repeat test, and build that into scheduling rather than treating it as failure.
• Check middle ear status before booking - an effusion turns one appointment into two.
• Optimise the sleep state deliberately: feed and settle timing is the single most controllable variable.
• Track the interval from referral to definitive diagnosis as a service metric, not just the screening pass rate.
• Read the association between otolaryngology consultation and later diagnosis as confounding by complexity, not as a reason to refer less.

The statistics, in plain English

The adjusted hazard ratio of 0.46 for otolaryngology consultation looks alarming until you consider what a consultation means: children with syndromic features, middle ear disease or complex needs are referred, and those are the children whose diagnosis takes longer. This is confounding by indication and the authors treat it as such. The difference in hearing aid fitting age, 11.2 against 5.9 months, is a comparison between groups defined by their diagnosis timing, so it partly restates the exposure - but the six-month gap is large enough to matter clinically whichever way it is analysed, given what is known about early amplification and language outcomes.

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