Glycerol test is used for diagnosis of -

Ans. is 'a' i.e., Meniere's disease Investigations in Meniere's disease1) Tuning fork testso Tuning fork tests show sensorineural hearing loss :-i) Rinne testii) Weber testiii) ABC test---PositiveLateral ized to better earReduced in affected earPu re tone a u diometryo There is sensorineural hearing loss with affection of lower frequencies in early stages and the curve is of rising type. When higher frequencies are involved, curve becomes flat or a falling type.Speech audiometryo Discrimnation score is usually 55-85%.Special audiometry testso Indicate cochlear lesion :-Recruitment test is positiveSISI (short increment sensitivity index) score is better than 70%Tone decay test shows decay of less than 20 dB.Electrocochleographyo Normally, ratio of summating potential (SP) to action potential (AP) is 30%. In Meniere's disease, SP.; AP ratio is greater than 30% and is diagnostic of Meniere's disease.Caloric testo It shows reduced response on the affected side. Often, it reveals a canal paresis on the affected side (most common) but sometimes there is directional preponderance to healthy side or a combination of both canal paresis on the affected side and directional preponderance to opposite side.Glycerol testo Glycerol reduces endolymphatic pressure due to its dehydrating property and thus causes an improvement in hearing.Reverse glycerol testo Performed by using acetazolamide. Shows deterioration in the pure tone threshold and speech discrimination score.