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Objective: In this retrospective study the aim of the authors was to examine the effect of gentamicin on the individual semicircular canals after low dose, single injection intratympanal gentamicin therapy in Meniere's disease.Methods: Data of 32 patients treated between 2011 and 2015 were collected. The high frequency, high acceleration vestibuloocular reflex (VOR) gain was measured in the individual semicircular canals using video head impulse test immediately before the first intratympanal gentamicin instillation and approximately two months later.Results: In all cases 'AAO-HNS Class A' vertigo control could be attained at least for several months. In 13 cases only one instillation was necessary. In the other 19 cases the attacks returned after a few months. In 11 cases the injection had to be repeated a second time, in 4 cases 3 injections, in 2 cases 4, in 1 case 5 injections and in another 6 injections were necessary. The initial VOR gain was normal in all cases and two months after one injection it decreased in average by 40% in a highly significant manner. However, there were cases in which, although the patients became free of attacks, the gain values remained normal.Conclusion: It was possible to demonstrate a significant correlation between the gain decrease of the individual canals. There was no prognostic correlation between the initial gain decrease after the first injection and the necessity of further injections. Gain values also decreased slightly but significantly in the lateral and posteriors canals on the contralateral, untreated side, possibly because of the missing disfacilitation from the treated side. [ABSTRACT FROM AUTHOR]

Objective: In this retrospective study, the aim of the authors was to examine the frequency of involvement of the individual semicircular canals (SCCs) in vestibular neuritis (VN) and to assess the degree of long-term recovery. A secondary aim was to retrospectively determine the usefulness of a three-step bedside oculomotor test (the HINTS-test) for the differential diagnosis of peripheral VN.Methods: 44 cases were evaluated during the acute phase and approximately two months later. The gain of the vestibuloocular reflex was determined using video-head-impulse test, carried out using Otometrics ICS Impulse Otosuite Vestibular V 1.2.Results: In 19 cases (43%), a typical, so called "superior" VN could be diagnosed; in 17 cases (38%), all three SCCs were involved; in 4 cases, an isolated inferior canal involvement was seen; and in another 4 cases, a slight, isolated horizontal canal involvement was registered. Slight, isolated horizontal canal vestibular neuritis causing acute vestibular syndrome has not yet been reported in the literature. A three-step bedside oculomotor examination, the HINTS-test (head-impulse test, examination of gaze evoked nystagmus, and test of skew-deviation), suggested peripheral involvement in all cases with superior pattern VN and in cases when all three SCC were involved. It indicated 'stroke' in cases with inferior pattern and in the cases with isolated involvement of the horizontal canal. At follow-up, the horizontal canal function normalized in 55%, the anterior canal in 38%, and the inferior in 38%. When all cases were pooled, 14 patients recovered completely. In cases with severe initial decrease of gain in the horizontal canal (initial value less than 0.5), the canals had a 50 per cent chance to recover significantly.Conclusion: In vestibular neuritis, in cases with severe decrease of gain in the horizontal canal (initial value less than 0.5), the canal has a 50 per cent chance to recover significantly. The vertical canals have worse prognosis, and especially the inferior canals seldom improve. Slight, isolated horizontal canal vestibular neuritis may cause acute vestibular syndrome, most probably by the same mechanism as full-blown vestibular neuritis. In these cases, the three-step bedside oculomotor test may indicate cerebellar stroke (may be false positive). [ABSTRACT FROM AUTHOR]