A critical evaluation of the glycerol test in Meniere's disease

From the literature it is apparent that the glycerol test is being used frequently to evaluate Meniere patients, with regard to the choice of treatment, and in particular to find those who are suitable for surgery with different decompressive procedures. In our previous investigations on such patients we found that they often are extremely good placebo responders and it was natural to evaluate how important such psychological factors would be for the outcome of the glycerol test. In a group of patients with typical objective and subjective symptoms of Meniere's disease, the glycerol test was applied twice to each patient. In one of the tests, the patient was told that we would expect hearing to improve. In the other test, where the actual amount of glycerol was the same, we had the solution prepared with a different taste, and the patient was informed that we now would expect the hearing to deteriorate. The sequence of the two tests was randomly chosen for each patient. Most frequently the patient would follow our instructions, i.e. obtained a poorer hearing threshold when instructed to, and vice versa. The results are discussed with a special view to the risk of selection of suggestion-sensitive patients by this test.