140 patients with various forms of sensorineural hearing loss were examined via 
the glycerol test (Klockhoff). In 66% of the cases with Menière's disease, a 
typical temporary threshold shift could be seen. 17 patients with fluctuating 
hearing loss of unknown etiology without vestibular symptoms showed a similar 
effect; they were classified as belonging to the group of the cochlear type of 
Menière's disease. In 34% of cases with clinically assured diagnosis of 
Ménière's disease, glycerol did not induce improvement in hearing. Repeated 
glycerol tests revealed varying results; shortly after a Menière attack, the 
glycerol test was usually negative, whereas shortly before the next attack the 
glycerol test changed to positive. These data support the specificity of the 
glycerol test: The results depend on the presence of endolymphatic hydrops at 
the time of examination. Positive results of the glycerol test were also seen in 
the cases of reduced sensorineural hearing associated with syphilis, as well as 
in cases of cerebrospinal pressure changing synchronously with fluctuating 
hearing loss (Lindsay and Zajtschuk). In all other cases of sensorineural 
hearing losses, no positive effect of the glycerol test has been found.