Ryota Oku

Subjective visual vertical in acute attacks of Ménière's disease.

Objectives: To investigate whether or not and how often there is otolith dysfunction in an acute attack of Ménières disease. Patients: Twenty-two definite cases of unilateral Ménières disease diagnosed in accordance with the 1995 criteria of the American Academy of Otolaryngology-Head and Neck Surgery for Ménières disease. Intervention: Subjective visual vertical (SVV) test was performed before, at, and after acute attacks on 22 patients with unilateral Ménières disease who showed normal tilts of SVV before acute attacks. Main Outcome Measure: Abnormal tilts of SVV. Results: Of 22 cases, 14 (63.6%) with unilateral Ménières disease showed abnormal tilts of SVV in acute attacks. The tilts were toward the side of the affected ear in 13 (92.9%) of them. Abnormal tilts returned to normal within a few weeks after the acute attacks in 12 (85.7%) of the 14 cases with unilateral Ménières disease. Conclusion: Otolith dysfunction occurred in acute attacks in a considerable number of patients with Ménières disease. Subjective visual vertical can be used as a good tool for the evaluation of otolith dysfunction at acute attacks in patients with Ménières disease.

Otolith dysfunction during vertiginous attacks in Ménière's disease

Objective—Vertiginous attacks of Ménières disease (MD) are characterized by various types of vertigo, namely rotatory vertigo, dizziness and drop attack. When a patient complains of dizziness without spontaneous nystagmus, otolith dysfunction cannot be ruled out. The purpose of this study was to evaluate otolith dysfunction during vertiginous attacks of MD or delayed endolymphatic hydrops. Material and Methods—Vestibular function tests were carried out daily for several days in 11 patients (MD, n = 9; delayed endolymphatic hydrops, n = 2) during vertiginous attacks. Otolith function was evaluated by means of the static torsional position of both eyes [static ocular torsion (OT)] whilst in an upright position. We defined otolith dysfunction as an abnormal change (range) in OT without spontaneous nystagmus or as an abnormal change in OT without a change in spontaneous nystagmus. Results—Four patients had an abnormal change (range) in OT without spontaneous nystagmus or an abnormal change in OT without a change in spontaneous nystagmus during vertiginous attacks of MD. Conclusions—Otolith dysfunction occurs in patients during vertiginous attacks of MD. In cases of ataxia without spontaneous nystagmus, otolith dysfunction most likely causes atypical attacks of MD.

Measurement of the endolymphatic sac potential in human.

In this study, we measured human endolymphatic sac potential (ESP) in 8 patients with vestibular schwannoma and in five patients with Ménières disease during surgery. ESP was measured with a glass electrode filled with 154 mM NaCl and with an outside tip diameter ranging from 2 to 3 microm. The mean value of human ESP in patients with vestibular schwannoma was +13.3+/-1.9 mV. Since electron microscopy showed that the endolymphatic sacs of the eight patients with vestibular schwannoma were normal in the ultrastructures the value can be close to normal human ESP. While in Ménières disease, three cases showed low potentials and two cases showed almost the same values observed as in the eight patients with vestibular schwannoma. In the two cases with Ménières disease, the epithelial cells of the endolymphatic sac were preserved. Our study can be considered as the first successful measurement of human ESP and revealed the existence of Ménières disease having normal endolymphatic sac in function as well as morphology.