Pupillary pharmacologic test in Ménière's disease: a useful method for routine diagnosis.

The role of the parasympathetic system in Ménière's disease was investigated by a pupillary pharmacologic test (methacholine test), using a computed infrared pupillograph. The test was performed in Ménière's disease (16 cases), other vertiginous disorders (23 cases) and normal subjects (10 cases). The results confirmed the presence, during the attack stage of Ménière's disease in 75% of cases, of an abnormal sensitivity of the iris musculature to methacholine, prevalent on the affected side, and an increasing pupillary asymmetry. These features were found in 17% of the patients with other vertiginous disorders and in none of the control subjects. The parasympathetic dysfunction is interpreted as a supersensitivity of central origin and seems directly related to the disease. It is proposed that the methacholine test acts as a complement to the glycerol test in the diagnosis of Ménière's disease.