Koichiro Shigeno

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.

Superficial Siderosis of the Central Nervous System

This is a case of superficial siderosis of the central nervous system (SSCN). The diagnosis of SSCN was based on the result of T2-weighted magnetic resonance imaging and on suggestive clinical manifestations. The pure-tone audiogram showed bilateral progressive sensorineural hearing loss with a poor speech discrimination score and Jerger type IV. The remarkable elevation of the detective threshold of cochlear microphonics on electrocochleography was found and distortion product otoacoustic emission (DPOAE) showed no response: These electrophysiologic examinations, including electrocochleography and DPOAE, revealed that the progressive sensorineural hearing loss in this case was caused by both retrocochlear and cochlear damages.

Importance of Cervical Muscles in Galvanic Body Sway Test

Retro-auricular galvanic stimulation in Rombergs posture elicits body sway which consists of an initial response (IR) and a deviation response (DR). Generally, anodal stimulation of the right side elicits IR to the left and DR to the right. We measured the deviation response (VDR) in various conditions in normal subjects. There was no significant difference between mean VDR in the standing posture weighted on the left foot (0.49 +/- 0.17 cm) and on the right foot (0.39 +/- 0.20 cm). Stimulation in the squatting posture also elicited IR to the left and DR to the right. Stimulation of the right side produced DR backward and to the right in the condition of the head facing to the right, and forward and to the right in the condition of the head facing to the left. The same body sway response as the after galvanic stimulation was also induced by non-galvanic maneuvers like inclining the head or moving the finger. Anodal stimulation in the sitting posture elicited slight but apparent head inclination to the stimulated side. These results suggest that cervical muscles play an important role in the galvanic body sway test (GBST), viz. IR and DR seemed to be secondarily produced by changes in the muscular tension of the neck.

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.

Observations of Elderly Patients with Vertigo from 1969 to 1983

We surveyed elderly patients over 65 years of age who were treated for vertigo or dizziness in our Clinic between 1984 and 1993. There was a significant increase from 17.2% in the earlier 5-year period to 21.7% in the later period. This increase exceeded the growth in the elderly population in Nagasaki. Female patients showed a greater increase than male patients, especially among patients in their 70s. There were various causes in these aged patients, but BPPV and Cerebro-vascular disorders were common. From these results, vertigo or dizziness in aged patients might be prevented by suitable treatment of factors causing Cerebro-vascular disorders, such as hypertension.

Positional Nystagmus Induced by Infusion of Saturated NaCl Solution into the Tympanic Cavity

Trans-tympanic infusion of saturated sodium chroride solution into the tympanic cavity was performed in eleven rabbits. Nystagmus was induced in 8 rabbits. The time course of the nystagmus was as follows: spontaneous nystagmus to the injected side, positional and positioning nystagmuses changing to different directions by alternation of the head position were initiated 15-30 minutes after infusion. Spontaneous nystagmus subsided within an hour, although, positional and positioning nystagmuses persisted more than 3 hours. The direction of positional and positioning nystagmuses was to the left when the head was held with the right side down, to the right with the left side down, to the injected side with the nose-up position, and to the non-injected side with the nose-down position, respectively. These nystagmuses disappeared in 24 hours after infusion and caloric response was preserved. Only one rabbit showed persistence of the positional nystagmus to the right when the head was held with the right side down, and to the left with the left side down. Several variable nystagmuses such as pure vertical nystagmus, equivalent to rotatory nystagmus in humans, or rotatory vertical nystagmus presumably originating in the vertical canals were observed in some rabbits. A temporal bone pathology study revealed mild endolymphatic hydrops in the cochlea and saccule, deformed and dissolved cupula in the vertical canals. In addition, basophilic reticulated materials in the endolymphatic and perilymphatic spaces, and homogenous basophilic materials around the maculae and cristae were observed in a case with persistent positional nystagmus.