Range of Peak Head Velocity in Video Head Impulse Testing for Pediatric Patients

Objective:To examine peak head velocity in video head impulse testing of pediatric patients and its effect on vestibulo-ocular reflex (VOR) gain.Study Design:Retrospective case review.Setting:Tertiary referral center.Patients:Pediatric patients ages 3 to 18 years old who underwent video head impulse testing during clinical evaluation of dizziness and/or imbalance.Intervention(s):Conducted video head impulse test (vHIT) in horizontal, left anterior-right posterior (LARP), and right anterior-left posterior (RALP) planes.Main Outcome Measure(s):Peak head velocity and mean VOR gain for individual semicircular canals in different age groups.Results:For the horizontal plane, vHIT peak head velocity greater than 150degrees/s was achieved in 43 to 63% of 219 patients. In contrast, vHIT peak head velocity greater than 150degrees/s was achieved in only 3 to 14% for the LARP and RALP planes. Analyses of differences in mean VOR gains among three ranges of peak head velocity (100-125degrees/s, 126-150degrees/s, and >150degrees/s) by paired-t tests were not significant (p>0.05) within individual patients. Mean VOR gains of three vertical canals in younger patients were significantly lower with higher peak head velocities compared with older children (p<0.05).Conclusions:Peak head velocities of greater than 150degrees/s may not be feasible in a large proportion of children and adolescents, especially in LARP and RALP planes. However, such high velocities may not be necessary in the pediatric population since VOR gain values obtained at lower peak head velocities of 100 to 150degrees/s were found to be comparable to those observed at higher velocities.