gms | German Medical Science

Introduction: The assessment of the vestibulo-ocular reflex (VOR) with the head- impulse test of Halmagyi is essential in the diagnosis of peripheral vestibular hypofunction in patients with vertigo. The vHIT represents a new method to objectify this technique. The measurement of gain is supposed to quantify the VOR.

Methods: 50 patients with unilateral peripheral vestibular hypofunction (24 with onset of symptoms <72h) and a control group of 25 healthy subjects were tested by vHIT and caloric testing. We compared VOR gain (considered pathological: <0,8) and gain asymmetrie (GA) of vHIT with the canal paresis (CP) of caloric testing (pathological: <25%). Catch-up saccades, overt- and covert-saccades, were also evaluated.

Results: The vHIT was 32% sensitive and 96% specific for the diagnosis of peripheral vestibular hypofunction. A normal VOR gain was observed in 68% of patients. Further, 31% of patients and healthy subjects had a GA to the wrong side (defined by the weaker side which was detected by caloric testing). Catch-up saccades were observed in 68% of patients: Isolated overt-saccades in 42%, isolated covert-saccades in 2% and combination of both in 24%.

Conclusions: The sensitivity of vHIT-Gain for the diagnosis of peripheral vestibular hypofunction seems very low. Catch-up saccades detected by vHIT at the same time seem reliable but so far are not objective. To improve the clinical value of vHIT, standardization of the best algorithm for gain-calculation, further research about the significance of gain asymmetry and objective criteria for the detection of Catch-up saccades are needed.