Towards a new staging of Ménière’s disease: a vestibular approach
Ménière’s disease (MD) is characterised by intermittent episodes of vertigo, fluctuating sensorineural hearing loss, tinnitus and aural pressure. Histopathologically, endolymphatic hydrops are seen initially in the cochlear duct and saccule, and with progression of the disease subsequent involvement of the utricle and semicircular canals occurs. The aims of this study are: 1) to assess the function of the saccule, utricle and three semicircular canals using cervical vestibular evoked myogenic potential (cVEMP), ocular VEMP (oVEMP) and video head impulse test (vHIT) in Ménière’s patients, and 2) to correlate the findings with the different stages of MD. Forty patients diagnosed with unilateral definite MD according to the AAO-HNS (1995) criteria were tested. They were divided into four subgroups according to the stage of MD using the average of 500, 1000, 2000 and 3000 Hz pure tone thresholds of the worst documented audiogram during the 6-month interval before examination. A control group of 40 healthy age-matched adults was equally divided into four corresponding subgroups according to their pure tone average. 500 and 1000 Hz tone burst air conduction cVEMP and oVEMP tests, bithermal caloric test and video HIT for all semicircular canals were recorded for both groups. The results of this study showed that the highest prevalence of abnormalities in Ménière’s patients were seen in the PTA (85%), followed by cVEMP (72.5%) and oVEMP (67.5%). Caloric test abnormalities followed with a lower prevalence of 32.5%. The vHIT presented the lowest prevalence of abnormalities with 20% in the lateral canal, 7.5% in the anterior and 5% in the posterior. This pattern of abnormality agrees with the histopathological pattern of hydrops formation in the vestibular system. The findings of the current study suggest that with the advancement in the stage of MD, abnormal cVEMP, oVEMP, caloric and vHIT responses occur following the histopathological evidence of progression of the disease from the saccule up to the semicircular canals. Based on these findings, the authors suggest a new staging scheme for MD.