Is dehydration test using isosorbide useful in Meniere's disease?

Abstract

Conclusion: The dehydration test using isosorbide is well tolerated when used to detect endolymphatic hydrops and may also be used to improve the sensitivity of ECoG performed on patients with MD, especially in poor hearing at low-frequency.Objective: This prospective study was to explore the diagnostic utility of a dehydration test, administering oral isosorbide, which has been used to treat Meniere's disease (MD).Method: Electrocochleography (ECoG) and the dehydration test with isosorbide were performed on 32 patients diagnosed with definite diagnosed MD. Isosorbide (120mL) was orally administered after baseline audiometric testing, and the testing was repeated 3h later. The dehydration test was considered positive when improvements in hearing thresholds of 10dB or more were evident at two or more frequencies, or the speech discrimination score increased by 12% or more. An abnormal ECoG finding was defined as an SP/AP (summating potential/action potential) ratio 0.4.Results: The dehydration test using isosorbide was positive in 10 of 32 patients (31.3%). The test was not associated with development of any serious side-effect. Abnormal ECoG findings were noted in 14 of 32 patients (43.8%). When endolymphatic hydrops was defined as an abnormal ECoG or a positive dehydration test, the condition was detected in 21 of 32 patients (65.6%). The positive result in dehydration test was significantly higher in patients with above moderate hearing loss at low-frequency.