What Precautions are Needed for Best vHit Results in the Pediatric Population?

Question

Answer

The Video Head Impulse Test (vHIT) is an instrumented technique that is used to help diagnose reduction in vestibular function in one ear versus the other. vHIT is rapid, non-invasive, simple diagnostic test for detecting vestibular deficits in children and there should be needed special practical considerations when administering vHIT in children.

Halmagyi et al. introduced the video head impulse test (vHIT) in 1988¹, which quantitatively evaluates the vestibulo-ocular reflexes at physiological frequencies. Since it is easy to use in the outpatient clinic, there is a growing interest in the clinical usefulness of vHIT.

Furthermore, vHIT is advantageous for testing children's vestibular function, as it is performed without causing darkness or dizziness, which are the major factors that cause fear in children.

The vHIT results showed a higher percentage of artifacts in children than in the adults. More careful efforts are required to obtain more accurate results during the test, and it is necessary to check for technical errors while interpreting the results.

In children, more caution is needed while performing and interpreting the test results because of the high incidence of artifacts and it is difficult to accurately diagnose pediatric dizziness because the causes of dizziness in the children differ from those in adults. Difficulties in history taking and physical examination can present challenges for diagnosis.

A previous study suggested that vHIT can be applied to babies older than 3 months. However, they also mentioned limitations due to the short concentration and inability to gaze.

In spite of the benefits of vHIT, there are some challenges when testing children. Some reported pitfalls include loose goggles, inability to follow directions, frequent eye blinks, wandering gaze, decreased attention span, noncompliance, and apprehension for receiving head impulses.^2-3-4

Following are the points based on my personal experiences and some points are taken from different recourses to understand the practical implication of vHIT testing in children. Definitely vHIT testing in children won’t be easy and results won’t be perfect.

• Gaze stability. Eyes moves a lot so Focus and re-focus counts a lot;
• Eye opening. Continuous talking, singing song or poems to get attention of child towards you;
• Practice and rehearsal. Play and rehearsal with a lot of accessories helps you to engage the child with you;
• Comfortable position;
• Clear oily skin;
• Timing. Shouldn’t be sleeping time of baby, test should be preferred after sleep;
• Feed. Baby should have adequate feed. Wouldn’t be hungry;
• Several visits. It may take several visits to complete the test;
• Adequate time. You should have adequate time for test so that your next patient won’t be disturbed;
• Additional tester. You have one trained assistant with you that helps you to engage the child in different activities.

Resources for More Information 

For more information, visit https://www.inventis.it/en-na

References

1. Kim, K. S., Jung, Y. K., Hyun, K. J., Kim, M. J., & Kim, H. J. (2020). Usefulness and practical insights of the pediatric video head impulse test. International Journal of Pediatric Otorhinolaryngology, 139, 110424. https://doi.org/10.1016/j.ijporl.2020.110424
2. Hamilton, S. S., Zhou, G., & Brodsky, J. R. (2015). Video head impulse testing (VHIT) in the pediatric population. International Journal of Pediatric Otorhinolaryngology, 79(8), 1283–1287. https://doi.org/10.1016/j.ijporl.2015.05.033
3. Wiener-Vacher, S. R., & Wiener, S. I. (2017). Video Head Impulse Tests with a Remote Camera System: Normative Values of Semicircular Canal Vestibulo-Ocular Reflex Gain in Infants and Children. Frontiers in Neurology, 8, 434. https://doi.org/10.3389/fneur.2017.00434
4. Hülse, R., Hörmann, K., Servais, J. J., Hülse, M., & Wenzel, A. (2015). Clinical experience with video Head Impulse Test in children. International Journal of Pediatric Otorhinolaryngology, 79(8), 1288–1293. https://doi.org/10.1016/j.ijporl.2015.05.034