Gentamicin vestibulotoxicity with modern systemic dosing regimens: a prospective study using video-oculography

Abstract

Objectives: To determine the incidence of gentamicin vestibulotoxicity with current dosing regimens, and to evaluate the feasibility of routine video-oculography on all patients given gentamicin.

Materials and methods: In this prospective incidence study serial horizontal vestibulo-ocular reflex (HVOR) gain measurements were recorded using video-oculography on adult inpatients receiving intravenous gentamicin. The primary outcome was the proportion of patients developing impairment of their HVOR gain.

Results: After exclusions, 42 patients were included in the analysis. Three patients (7.1%) developed asymptomatic vestibulotoxicity, exact 95% confidence interval 1.5–19.5%. In two of these patients the deficit resolved within several hours. No patients developed symptomatic vestibulotoxicity. There was no evidence for a generalised reduction in group HVOR gain with time. HVOR gain was not associated with total gentamicin dose, dynamic visual acuity or subjective imbalance.

Conclusions and significance: Gentamicin may cause reversible, asymptomatic vestibulotoxicity. Video-oculography may be useful to monitor for vestibulotoxicity in patients treated with gentamcin; however, testing all patients routinely may be challenging.     

Prognosis in Bilateral Vestibular Hypofunction

Objectives/Hypotheses: The outcomes of patients with bilateral vestibular hypofunction vary widely. Some resume relatively normal activity within months, whereas others have a more debilitated course. This study sought to identify factors that may affect outcome. Study Design: A retrospective review of patients treated for bilateral vestibular hypofunction over a 2-year period at a neurotology clinic. Methods: Patients' medical charts, electronystagmography data, rotatory chair testing, and posturography results were reviewed. Subjective and objective measures were used to evaluate outcome. Results: Bilateral vestibular hypofunction was diagnosed in 35 patients. Improvement after vestibular rehabilitation therapy was noted in 18 patients (51%), whereas 12 (34%) showed little or no change and 5 (15%) were not available for follow-up. The patients without improvement were more likely to have a chronic disorder as a cause of the vestibulopathy and had more medical comorbidities, on average, when compared with those who improved. Lower gains and time constants on rotatory chair testing were also seen in the group that did not improve. Conclusions: Poor rehabilitation results may be attributable to increased severity of vestibular insult, progressive peripheral or central vestibular dysfunction, and multiple medical problems.