Masaaki Yamane

Long-term Modifications of Vertical and Horizontal Vestibulo-ocular Reflex Dynamics in Man: I. After Acute Unilateral Peripheral Vestibular Paralysis

Horizontal (HOR) and vertical (VERT) vestibulo-ocular reflex (VOR) responses to whole-body triangular velocity profiles with constant accelerations of 10, 15 and 20 deg/s2 were studied in two populations: normals, and patients with acute unilateral peripheral vestibular paralysis. The effect of this type of unilateral deficit on VOR gain and long time constant were determined as well as the time course of the compensation processes for HOR and VERT VOR dynamics. In the patient population, HOR VOR gain was asymmetric post deficit, being, on average, 50% and 75% of normal for rotations toward and away from the deficit, respectively. For the VERT VOR, on average, a symmetric 66% reduction occurred. The VERT VOR time constant was marginally affected by the deficit. HOR time constants were reduced for both directions of rotation. HOR and VERT VOR gain was within normal limits 1-3 months following an acute paralysis; time constants required a longer recovery period. Our results indicate that a unilateral deficit causes a markedly different alteration for HOR VOR dynamics compared to the effect on VERT VOR.

Neuro-otological and Neuropathological Findings in two Cases with Machado-Joseph Disease

We report chronological changes of neuro-otological findings and associated neuropathological findings in 2 patients. Concerning gaze limitation, upward gaze was primarily disturbed, followed by downward gaze and abduction. Adduction tended to be preserved although convergence was disturbed at the early stage. And, upward gaze limitation was followed by loss of oculocephalic responses (OCRs). Bells phenomenon was preserved until the late stage of the disease. Caloric nystagmus was absent at the early stage. One patient showed dissociation between nystagmus and vestibulo-collic reflex in the caloric test at the early stage of the disease. Neuropathological examination revealed gliosis in the interstitial nucleus of Cajal and the MLF as well as neuronal loss and gliosis in the oculomotor nuclei. The vestibular nuclei also showed gliosis and atrophy of nerve cells.

Analysis of Stapedial Reflex in Neuromuscular Diseases

An impedance audiometric analysis of the stapedial reflex was carried out in 17 patients with motor neuron disease (MND), 11 with myasthenia gravis (MG), and 3 myotonic dystrophy (MD). The features examined were the threshold and latency parameters and the response pattern of the reflex. All groups had mean reflex thresholds within normal limits (80-90 dB hearing level). The MND group showed a lengthened mean reflex latency (L1). The MG group showed an unstable response pattern to 10-second tone stimuli and a lengthened L1. Half the group demonstrated abnormal decay of the reflex. The MD group showed a reduction in the growth of averaged reflex in response to stimuli with short interstimulus intervals (2.6 s) and the L1 and C50 were lengthened.

Stapedial reflex in Parkinson's disease

In 27 patients with Parkinsons disease (PD), stapedial reflexes were measured using impedance audiometry and compared with those of 11 age-matched control subjects. The reflex threshold of PD patients was lower than that of control subjects. A prolongation of contraction time (C50) and relaxation time (D50) was revealed. Between patients with and without L-dopa, there was no significant difference for any reflex parameter. But, the D50 of patients without anticholinergic drugs was longer than that of patients with anticholinergic drugs. The authors could not find any relationship between the severity of PD and the reflex parameters. The authors assume that the prolongation of reflex parameters might be attributed to the hyperactivity of the indirect pathways of the stapedial reflex.

Immunological analysis of IgG and other protein fractions in endolymph obtained from endolymphatic sac of Meniere patients and a control.

During endolymphatic sac surgery on patients with Menieres disease, very small amounts (1 microliter) of the intra-sac endolymph were obtained with micro-glass pipets. An immunological assay of microanalysis of the protein by the single radial immunodiffusion (SRID) method was applied to 2 patients, one with bilateral involvement and the other unilateral. Among the protein fractions Alb, IgG, IgM, IgA, C3, C4, transferrin and alpha 2M, the concentrations of IgG were relatively higher, especially in the Meniere patient in the active stage. From 2 other patients and a control deaf patient with temporal bone fracture, the same amounts of endolymph were obtained, accompanied by a tiny specimen of the outer wall of the sac. When a radio-immunological procedure was applied to the endolymph and the homogenized sac, the specific concentration of IgG was higher in the Meniere patients than in the control.

Detection of Delayed Endolymphatic Hydrops by the Furosemide Test

Delayed endolymphatic hydrops, an entity which can be differentiated from Menieres disease, was first reported simultaneously by Nadol et al. (1975) and Wolfson & Leiberman (1975) and specified by Schuknecht (1978). They diagnosed it from the anamnesis of patients and confirmed the hydropic condition of the labyrinth solely by evidence obtained from surgical procedures such as labyrinthectomy. The aim of the present study was to emphasize the usefulness of the furosemide test for distinguishing this entity before surgery by detecting the hydropic condition in the labyrinth. In these 3 years, we encountered 11 cases of endolymphatic hydrops, 9 ipsilateral and 2 contralateral, in our clinic (Univ. of Tokyo Hospital). Among the ipsilateral cases, the estimated genesis of pre-existing hearing loss was most frequent in mumps (44%). The result of the furosemide test in this group was 89% positive. On the basis of this result, we have been able to choose the method of treatment, i.e. 4 cases treated by epidural shunt operation on the endolymphatic sac, 2 by labyrinthectomy, one by cochleosacculotomy and 2 by medication with steroids and diuretics. In the 2 contralateral cases, one was treated by epidural shunt and the other by medication. The authors are therefore able to confirm the usefulness of the furosemide test for detecting delayed endolymphatic hydrops.

UPBEAT NYSTAGMUS INFLUENCED BY POSTURE: REPORT OF TWO CASES

Two cases of vertical gaze nystagmus, which were influenced by posture are reported. In both cases, upbeat nystagmus (UBN) on forward gaze in upright and supine positions changed to downbeat nystagmus (DBN) in prone position. Convergence had no influence on the vertical nystagmus. A CT scan revealed an atrophy of the anterior vermis of the cerebellum in the first case. The UBN of the second case was suspected to be associated with lesions in the brachium conjunctivum. The authors concluded that both UBN and DBN were not completely separate, but they could coexist in cases with certain lesions in the posterior cranial fossa.

Serous Otitis Media in Amyotrophic Lateral Sclerosis

Serous otitis media (SOM) is a common disease, the cause of which is not always clear. In this paper authors report the high incidence of SOM among the patients with amyotrophic lateral sclerosis (ALS). Furthermore, a comparative study about ALS and other diseases shows higher incidence of SOM in ALS. Our study indicates that SOM in ALS seems to be mainly due to muscular disturbance of eustachian tube caused by ALS, although the influence of long term supine position and nasopharyngeal irritation by nasogastric feeding tube cannot be denied in the development of SOM.

Eperisone Treatment for Dizziness, Vertigo, Hearing Loss and Tinnitus

The effectiveness, safety and usefulness of Eperisone were evaluated in 86 patients with dizziness or vertigo, hearing loss and tinnitus in a six-institution open trial. The patients also complained of headache, stiff shoulders or stiff neck. Headache, stiff shoulders and stiff neck were markedly relieved with headache disappearing completely in 46%.Dizziness and vertigo responded subjectively and objectively to treatment in 51% of patients. Hearing loss and tinnitus, however, were unchanged. Side effects were noted in only 4.1%, and they were mild.

NEURO-OTOLOGICAL FINDINGS IN PATIENTS WITH SPINOCEREBELLAR DEGENERATION: WITH SPECIAL REGARD TO THE DURATION OF ILLNESS

Neuro-otological findings in 150 patients with spinocerebellar degeneration were analyzed based on the duration of illness since onset. The results of each kind of neuro-otological examination varied in close relation to the duration of illness. Also, the results of each kind of examination correlated closely. In particular, the optokinetic nystagmus test and the visual suppression test correlated most closely. Neuro-otological examinations were confirmed to be of great value in gauging progression in spinocerebellar degeneration.