Hearing assessment and childhood hearing loss — structured clinical encounter

Station brief (candidate)

You are the paediatric registrar on the postnatal ward. A term baby, born after an unremarkable pregnancy, refers on the otoacoustic emissions newborn hearing screen in both ears. The parents are anxious and have many questions. The team asks you to explain the screening programme timeline, the diagnostic test that will confirm or exclude a loss, how that test distinguishes conductive from sensorineural hearing loss, what to look for in the aetiology, and the plan if a permanent loss is confirmed. The baby was noted to have a few petechiae at birth and a slightly small head circumference, but is feeding well and is otherwise normal. You have 12 minutes with the team and 5 minutes for examiner discussion. [6]

Information available on request

• Term, appropriate-for-gestational-age baby; unremarkable antenatal history; no family history of deafness. [6]
• Otoacoustic emissions screen: refer bilaterally; no risk factors other than petechiae and a small head circumference. [6]
• A few facial petechiae noted at birth; occipitofrontal circumference on the 3rd centile; normal tone and feeding; no dysmorphism. [7]
• No history of neonatal intensive care stay, ventilation or jaundice. [4]
• The parents ask whether the baby is deaf and what happens next. [6]

Tasks

1. State the milestones of the universal newborn hearing screening programme and the timeline for this baby, and explain what a diagnostic test will show. [6]
2. Explain how the diagnostic test distinguishes conductive from sensorineural hearing loss. [5]
3. Given the petechiae and small head circumference, name the congenital infection to investigate and state how and when it is confirmed. [7]
4. Outline the family-centred plan if a permanent sensorineural hearing loss is confirmed, and the reason for the urgency. [1]

Discussion points (examiner)

• The candidate should state that the diagnostic test is an auditory brainstem response performed with the baby asleep or sedated, giving frequency-specific thresholds, and that adding bone conduction reveals an air-bone gap in conductive loss versus concordant air and bone elevation in sensorineural loss. [5]
• The candidate should identify congenital cytomegalovirus as the commonest acquired cause of permanent childhood hearing loss, confirmed by polymerase chain reaction on saliva or urine within the first three weeks of life, and note that symptomatic congenital CMV is treated with a six-month course of valganciclovir. [7]
• The candidate should state the one-three-six milestones and explain that the urgency reflects the critical period of auditory development, with early intervention by six months so language outcomes approach those of hearing peers. [6]
• The candidate should volunteer that a passed newborn screen does not guarantee hearing for life, and that any later speech delay or regression must trigger re-assessment because CMV, the enlarged vestibular aqueduct and some GJB2 variants cause delayed-onset or progressive loss. [4]

Marking grid

• Excellent: fluent on the 1-3-6 milestones, the diagnostic ABR with bone conduction, the conductive-versus-sensorineural distinction, the CMV diagnosis and treatment, and the critical-period rationale; communicates the plan to anxious parents with empathy and honesty. [1]
• Pass: knows the milestones and that an ABR confirms the loss; identifies CMV; outlines early intervention; some uncertainty on the conductive-versus-sensorineural distinction or the timing of CMV confirmation. [6]
• Borderline: reassures the parents without a clear diagnostic plan, or confuses otoacoustic emissions with auditory brainstem response and cannot explain why a NICU baby needs AABR. [5]
• Fail: misstates the milestones, offers surgery for the screening refer, or does not recognise the need to follow up a refer to a confirmed diagnosis. [6]