Background: The differential diagnosis of a dizzy patient >4 yrs old is often aided by videonystagmography
(VNG) testing to provide a global assessment of peripheral and central vestibular
function. Although the value of a VNG evaluation is well-established, it remains unclear
if the VNG test battery is as applicable to the pediatric population as it is for
adults. Oculomotor testing specifically, as opposed to spontaneous, positional, and
caloric testing, is dependent upon neurologic function. Thus, age and corresponding
neuromaturation may have a significant effect on oculomotor findings.
Purpose: The purpose of this investigation was to describe the effect of age on various tests
of oculomotor function during a monocular VNG examination. Specifically, this study
systematically characterized the impact of age on saccade tracking, smooth pursuit
tracking, and optokinetic (OPK) nystagmus.
Research Design: The present study used a prospective, repeated measures design.
Study Sample: A total of 62 healthy participants were evaluated. Group 1 consisted of 29 4- to
6-yr-olds. Group 2 consisted of 33 21- to 44-yr-olds. Each participant completed a
standard VNG oculomotor test battery including saccades, smooth pursuit, and OPK testing
in randomized order using a commercially available system.
Data Collection and Analysis: The response metrics saccade latency, accuracy, and speed, smooth pursuit gain, OPK
nystagmus gain, speed and asymmetry ratios were collected and analyzed.
Results: Significant differences were noted between groups for saccade latency, smooth pursuit
gain, and OPK asymmetry ratios. Saccade latency was significantly longer for the pediatric
participants compared to the adult participants. Smooth pursuit gain was significantly
less for the pediatric participants compared to the adult participants. The pediatric
participants also demonstrated increased OPK asymmetry ratios compared to the adult
participants.
Conclusions: Significant differences were noted between the pediatric and adult participants for
saccade latency, smooth pursuit gain, and OPK asymmetry. Saccade latency was significantly
longer for the pediatric participants compared to the adult participants. Smooth pursuit
gain was significantly less for the pediatric participants compared to the adult participants.
The pediatric participants also demonstrated increased OPK asymmetry compared to the
adult participants. Caution should be exercised when comparing pediatric test results
to adult normative values to avoid “false positive” diagnoses of central vestibular
involvement.
Key Words
dizziness - oculomotor - vertigo - vestibular testing - videonystagmography
