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The aim of this study was to correlate long-term vertigo control with reduction in vestibular function after intratympanic (IT) gentamicin therapy for unilateral Ménière’s disease. IT gentamicin injections were given as needed to control vertigo attacks. Vertigo frequency and changes in angular vestibulo-ocular reflex (AVOR) gain (measured using magnetic search coils and manual head thrusts) and caloric weakness were assessed before and after treatment. Better vertigo control after treatment was found with ≥60% reduction in quantitative ipsilateral horizontal semicircular canal AVOR gain from pre-treatment values and/or with caloric unilateral weakness (UW) >50%. However, no correlations were found between the continuous variables of vertigo control and either gain or gain recovery, nor between gain and UW because of the large variability in vertigo control in subjects with lesser reductions in these measures.

Because they are cumbersome, tests to determine the quantitative susceptibility of organisms to antimicrobial drugs are not performed routinely in many diagnostic laboratories. This paper describes a simple method of incorporating the antimicrobial drug in agar. It is an adaptation of the Rolinson and Russell technique which allows the determination of minimum inhibitory concentrations (MIC) of antimicrobial drugs for a large number of organisms. Results are comparable with those obtained when the standard agar dilution method is used. Strains of aerobic Gram-negative bacilli were tested by both methods using ampicillin (86 strains), cephaloridine (72 strains), trimethoprim (72 strains), and gentamicin (72 strains). Of the 302 tests thus performed, a difference in MIC of more than one double dilution was noted in only 11 tests. With one strain of Pseudomonas aeruginosa, however, it was not possible to detect ampicillin resistance by the method described in this paper.