Vertigo and electronystagmography in uni- and bilateral Ménière's disease

In this study we performed standardized measurements of spontaneous nystagmus (SN), caloric tests and velocity step tests on a well-defined group of 92 Ménière patients as part of a diagnostic protocol. The aim of the study was to look for results that could contribute to the diagnosis, but more specifically to a possible classification, of Ménière's disease. Relations with average hearing loss, shape of the audiogram, average hearing loss, duration and severity of perceived symptoms of disease and differences between uni-and bilateral Ménière's disease were studied. Directional preponderance (DP) in unilaterally affected patients and labyrinthine preponderance (LP) in both uni- and bilaterally affected patients were significantly more often directed towards the unaffected (uni) or least affected (bi) side (p = 0.007, p = 0.001, p = 0.002, respectively). DP was correlated with LP (uni: R = 0.615, p < 0.001; bi: R = 0.438, p < 0.01), which means that the DP can be seen as a latent SN, directed to the unaffected side. With the caloric test parameters LP and DP it was possible to find unilateral weakness. In unilateral disease a duration of disease <2 years resulted in small asymmetry in time constant (T(asym)), large LPs and LPs not only directed to the unaffected, but also to the affected side, whereas a longer duration of disease gave large T(asym) and small LPs that were only directed to the unaffected side. Patients suffered more severe vertigo in the first two years of the disease. Studying the shape of the audiogram, it was found that patients having an LP to the affected side, suggesting that this was a hyperactive labyrinth belonging to a beginning of the disease, never had a flat audiogram. In this study the LP was the best diagnostic parameter to find unilateral weakness in patients with Ménière's disease. Together with the duration of the disease, the severity of symptoms, the asymmetry in T and the shape of the audiogram, it was possible to find two subgroups in the group of patients with unilateral Ménière's disease. Vestibular data in association with other test results of the diagnostic protocol may contribute to a more sophisticated classification of Ménière's disease.