Module 16 · Populations

Paediatric vHIT

Developmental gain values and modified protocols
Clinical vignette
A 3-year-old boy is being assessed before bilateral cochlear implantation for congenital sensorineural hearing loss. Pre-implant vestibular screening is requested. Caloric testing is impractical at his age. With distraction provided by a toy held by his mother, vHIT is obtained using a remote camera system: right lateral 0.92, left lateral 0.46. The lateral canal asymmetry shapes the ear-of-implant decision.
Reading level:

Why paediatric vHIT matters

Vestibular dysfunction in children is under-recognised and under-tested. Children with congenital sensorineural hearing loss have a 30–50% prevalence of vestibular hypofunction; ear-of-cochlear-implant decisions, sports-readiness counselling, and tracking developmental motor milestones all benefit from objective vestibular data. vHIT is uniquely well suited to paediatric practice: it is brief, can be made playful, requires no caloric irrigation, and produces quantitative data even in young children.

Practical adaptations

Children under approximately 5 years cannot tolerate standard head-mounted goggles for long and may refuse the apparent strangeness of a headset entirely. Remote camera systems — cameras mounted on a tripod a metre from the child's face, tracking the eye and head via reflective markers stuck to the forehead — solve this problem and are the technique of choice for very young children[Wiener-Vacher SR 2017]. Older children (school age) typically tolerate standard goggles, particularly if the test is framed as a game and a parent or favourite character is the visual target.

Normative data

The largest paediatric normative dataset comes from Wiener-Vacher and colleagues[Wiener-Vacher SR 2017], using a remote camera system in 188 healthy children aged 6 months to 12 years. Key findings:

  • Reliable lateral canal vHIT is obtainable from approximately 6 months of age.
  • Mean lateral canal VOR gain is approximately 0.94 across the age range, with somewhat wider variance than in adults — paediatric SD is approximately 0.12 versus 0.08 in adults.
  • Vertical canal testing is technically more challenging and norms are less robust; reserve vertical-canal vHIT for older school-age children when possible.
  • Below age 5, expect ~10–15% of attempts to yield uninterpretable data due to cooperation issues.

Indications

The principal indications for paediatric vHIT:

  • Cochlear implant candidates: routine pre-implant vestibular screening. Asymmetric vestibular function favours implanting the worse-vestibulated side.
  • Delayed motor milestones with sensorineural hearing loss: combined audiovestibular deafferentation explains delayed walking and head-control in many syndromic conditions.
  • Post-meningitis: bacterial meningitis can produce both cochlear and vestibular damage; serial vHIT in the recovery phase identifies vestibular sequelae early.
  • Congenital syndromes: enlarged vestibular aqueduct syndrome, Pendred syndrome, Usher syndrome (where vestibular loss in Usher type 1 is part of the syndrome definition).
  • Sports-readiness: paediatric concussion clinics use vHIT among other tools to assess return-to-play timing.

Key teaching points

  • Reliable paediatric vHIT begins at approximately 6 months with remote camera systems.
  • Mean lateral canal gain ≈ 0.94 with wider variance than adults; expect 10–15% uninterpretable attempts in very young children.
  • Principal indications: CI candidacy, delayed milestones with SNHL, post-meningitis, syndromic deafness.
  • Pre-implant vHIT supports ear-of-implant decisions: implant the worse-vestibulated side first when audiological factors are balanced.

References

  1. Wiener-Vacher SR, Wiener SI. Video head impulse tests with a remote camera system: normative values of semicircular canal vestibulo-ocular reflex gain in infants and children. Frontiers in Pediatrics 2017;5:67. doi:10.3389/fped.2017.00067
  2. MacDougall HG, Weber KP, McGarvie LA, Halmagyi GM, Curthoys IS. The video head impulse test: diagnostic accuracy in peripheral vestibulopathy. Neurology 2009;73:1134–41. doi:10.1212/WNL.0b013e3181bacf85
Related