Keiji Moriya

Ultrastructure of the Chick Vestibular Ganglion and Vestibular Nucleus: A Scanning Electron Microscopic Study

The fine structure of the chick vestibular ganglion and vestibular nucleus was studied in three dimensions using a scanning electron microscope (SEM). NaOH and OSO4 maceration methods were applied to observe the configuration in the mechanically torn specimens. Also, Tanakas aldehyde prefix OSO4-DMSO-OSO4 method (A-O-D-O method) was applied to observe the intracellular structure in the fractured specimens. The surface of the ganglion cell and the nerve processes were seen to be covered with abundant thin fibrous tissues in the specimen treated with OSO4 maceration. This surface fibrous tissue was completely removed with the NaOH maceration method. As a result, the ganglion cell and nerve processes could be seen to be enveloped in the myelin sheath. In the fractured vestibular ganglion treated by the A-O-D-O method, there were three patterns of perikaryal myelination in the vestibular ganglion cells: heavily myelinated, lightly myelinated, and unmyelinated, respectively. In the perinuclear region of the vestibular ganglion cell, well developed and aggregated cytoplasmic organelles such as endoplasmic reticulum, mitochondria, and Golgi apparati were observed. In the perinuclear region of the Schwann cell relatively large mitochondria were characteristically observed. In the fractured view of the vestibular nerves, most of vestibular fibers were compactly myelinated. In the vestibular nucleus, the gathering of the neuronal cells were observed with the NaOH maceration method.

Biofeedback Therapy in the Treatment of Tinnitus

Seven patients were treated with electromyographic biofeedback therapy for intractable tinnitus which was supposed to be reinforced by mental distress and muscle tension. Three patients, who succeeded in decreasing electromyographic levels of the frontal muscle, were able to reduce tinnitus and relieve anxiety. One patient could eliminate tinnitus only during biofeedback sessions, but the efficacy was not continuous in daily life. The other three patients, who failed to decrease electromyographic levels, did not obtain favorable results. It is suggested that biofeedback therapy appears to be of greatest benefit when muscle tension and mental distress are the cause of magnification of the tinnitus symptoms.

Glial fibrillary acidic protein (GFAP)-like immunoreactivity in the vestibular endorgan of the rat

The distribution of glial fibrillary acidic protein (GFAP)-like immunoreactivity in the peripheral vestibular nervous system of normal adult rats was studied using immunohistochemical methods. The immunoreactivity was demonstrated at the light-microscopic level. GFAP-like immunoreactivity could be seen at the vestibular fibers terminating in the hair cells.

Glial fibrillary acidic protein-like immunoreactivity in the human fetal inner ear

The distribution of glial fibrillary acidic protein (GFAP)-like immunoreactivity (IR) was analyzed in the human fetal inner ear using immunohistochemical techniques. In the 11-week-old human fetal cochlea, nerve fibers labelled with GFAP had reached the basilar membrane, but innervation stained by antisera against GFAP to the hair cells reached only as far as the basal coil. In the 11-week-old human fetal vestibular organs, little GFAP-IR was present in the epithelia. In 14- and 15-week-old human fetal cochleae, rich immunoreactive neural networks were observed, including the inner spiral bundle. Many immunoreactive sites were found below inner hair cells in all coils. Outer spiral bundles in the first, second and third rows in the basal coil were labelled, but the outer spiral bundle in the third row in the apical coil was not stained by the antisera. In the macula utriculi, many heavily stained sites and a rich immunoreactive network in the sensory epithelium were labelled, while considerably fewer positive nerve fibers and sites were present in the sensory epithelia in the macula utriculi and cristae ampullares. These results suggest that GFAP-IR is a very useful marker of differentiation of Schwann cells in the peripheral nerve in the human inner ear.

Cell Culture Study of the Vestibular Ganglion Cells: Morphology and Immunohistochemical Activity

Incubation of vestibular ganglion cells from the rat fetus and chick embryos was successfully done demonstrating bipolar cells and two types of multipolar cells, small round cells and large cells, in the cell cultures produced. Vestibular ganglion cells were found to be highly irregular in size. Furthermore, the presence of neurotransmitters (choline acetyl-transferase and substance P) was confirmed immunohistochemically. Substance P positive cells had many bipolar cells and some multipolar cells. However, choline acetyl transferase positive cells had some small multipolar cells but few bipolar cells. These findings suggest that all vestibular ganglion cells do not have the same function.

Unilateral Psychogenic Hearing Loss due to Contusion of the Ear in Childhood; A Case Report.

A 10-year-old female with unilateral psychogenic hearing loss is discribed. The external causes of hearing loss were contusion to the ear region on three occasions. Hearing loss occurred suddenly after the first two occasions of contusion to the ear. Low damage hearing loss on pure-tone audiometry was revealed both times, and hearing was restored to normal completely for a few weeks. These cases of hearing loss were attributed to concussion of the inner ear. After the third contusion, hearing loss occurred suddenly in her right ear as it had the first two times. There was sensory-neural hearing loss on the right side in pure tone audiometry, however the auditory brainstem response and stapedial reflex were normal. The contradictions between subjective and objective data suggested a unilateral psychogenic hearing loss. This case was subsequently diagnosed as unilateral psychogenic hearing loss induced by the experience of contusion to the ear region. Hearing levels subsequently returned to normal without any psychosomatic treatment. These observations suggest that evaluation of the auditory brainstem response is important to diagnose psychogenic hearing loss.

Tympanic membrane temperature in a patient with vertigo.

Tympanic membrane temperature (TMT) is greatly influenced by the internal carotid artery and the jugular vein. Average human brain temperature is influenced by the differences between the temperature of the internal carotid artery and of the jugular vein. TMT has been used extensively as an indicator of brain temperature. Tympanic membrane temperature was measured in six healthy men (control group) and one patient with vertigo. In the control group, TMT showed considerable circadian changes parallel to the core temperature. In the patient with vertigo, TMT varied widely after the attack of vertigo. These data can provide a basis for the understanding of vertigo attacks.