Visual-vestibular interaction test in the diagnosis of vertigo in children.

Objective: The aim of this study has been to test to determine the diagnostic value of a visual-vestibular test with a rotatory cylindrical chamber in the diagnosis of peripheral and central vertigo in children.

Methods: Ten children affected by posttraumatic and migrainous vertigo were enrolled (group A): as a control group 10 healthy children were identified. All the children underwent to electronystagmography (ENG) recording: the children, head blocked, sat on a "Tonnies rotatory chair Pro model", which was placed in the middle of a rotatory cylindrical chamber (2 m in diameter and 1.9 m in height), and underwent to rotatory vestibular stimulation by Stop test, to optokinetic stimulation and to contemporary rotatory vestibular and optokinetic stimulation (visual--vestibular-ocular-reflex): opening the light on the stop test, by an angular velocity of 90 degrees s(-1) obtained from a chair subliminal acceleration of 0.5 degrees s(-2), and making for 60s the optokinetic stimulation by rotation of the optical contrasts to determinate a nystagmus with a opposite direction to the postrotatory nystagmus and homodirectional to optokinetic nystagmus (in both clockwise and counterclockwise directions).

Results: For the analysis of the results we have considered nystagmus mean gain and direction of visual-vestibular-ocular-reflex (VVOR) nystagmus. In group A, all the children presented a VVOR nystagmus homodirectional to vestibular-ocular-reflex (VOR). In control group, all the subjects presented a VVOR nystagmus homodirectional to optokinetic nystagmus.

Conclusions: In the healthy patients, VVOR nystagmus is always homodirectional to optokinetic nystagmus and indicates the optokinetic system prevalence on VOR. The presence of a VVOR nystagmus homodirectional to VOR indicates the absence of the optokinetic system prevalence due to a central nervous system (CNS) modification and highlights a CNS disease. These data show the diagnostic role of our visual-vestibular interaction test in children affected by vertigo.