Shigeto Nakajima

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.

Extracellular Fluid Pathway inside the Facial Nerve Fascicles

The extracellular fluid pathway in the facial nerve and the diffusion of a tracer from the facial nerve to other cranial nerves was examined in the rabbit. Sodium fluorescein solution was injected into either the facial nerve fascicles or the epineurial connective tissue as a tracer at the stylomastoid foramen and then localized by fluorescence microscopy. In the facial nerve, fluorescence was observed in the endoneurium and external nerve sheath (epineurium and perineurium) through the geniculate ganglion following injection into the nerve fascicles. The vestibular, trigeminal, and glossopharyngeal ganglia also showed fluorescence on the injection side in ganglion cells and intercellular connective tissues. The results suggested that the endoneurial connective tissue constitutes a diffusion pathway inside the facial nerve fascicles and that the extracellular fluid pathway from the facial nerve to these cranial ganglia may be related to the neural spread of inflammation or neoplastic metastasis.

Transient Deviation of Closed Eye on Head Torsion: A Kind of Neck-ocular Reflex

Electrooculographically, torsion of the head with closed eyes causes little appearance of VOR, but a transient ocular deviation (TOD) of about 30 degrees and a maximum velocity of not less than 200 degrees/sec. TOD occurs more significantly during torsion of the head alone than during rotation of the whole body, with a two-fold greater degree of deviation, suggesting the importance of the input from the cervical afferent. TOD occurs even in a condition in which torsion of the head is made to try with the head fixed and as a result of this maneuver, a torsional force is put on the neck toward the direction of head torsion, but the head does not rotate (vestibular afferent is inoperative). Thus, it is supposed that TOD occurs as a result of the fact that the lateral gaze center is activated by perception of the directional information of head torsion from the cervical afferent.

Scanning electron microscopy and immunoglobulins of the endolymphatic sac in Meniere's disease

SEM and immunoglobulin staining of the intradural portion of the endolymphatic sac (ES) were investigated. All 15 normal subjects, from fetuses to an 80-year-old adult, showed well arranged epithelial cells. In Menières disease (all 15 patients) the ES showed various types degeneration of the epithelial cells. Inner ear deafness experimentally produced by kanamycin injection showed a similar degeneration of the ES. IgG of the ES in Menières disease showed moderately evident deposits compared with normal subjects. However, these findings were also found to the same degree as IgG deposits in animal deafness produced by KM injection. From the above results it can reasonably be concluded that the degenerated findings of the ES and deposits of the IgG in Menières disease may possibly be the result of cochlear deafness.

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.

Experimental Direction-Changing Positional Nystagmus induced by Intra-Tympanic Infusion of the Drugs

比重の異なる薬剤を1側の中耳腔に注入する事によって, 比重の違いに応じた, 内耳性の方向交代性 (上向性及び下向性) 頭位眼振のモデルを作成する事ができた. エチルアルコールでは左右側位で方向交代性下向性, Nose up で非注入側向き, Nose down で注入側向きの頭位眼振が出現した. 重水では左右側位で方向交代性上向性, Nose up で注入側向き, Nose down で非注入側向きの頭位眼振が出現した. またアルコールを中耳腔に注入した兎側頭骨標本において, 外側半規管膨大部周辺に染色性の異なる遊出物を認めた.

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.

Anisocoria in Inner Ear Lesions

In experiments using rabbits, the pupil on the side of irritative inner ear lesion showed dilatation, and that on the side of paretic lesion showed constriction. In the clinical observation of patients with unilateral inner ear diseases (134 cases), anisocoria was recognized in 54.5%. In 68.5% of these, anisocoria was induced after applying a drop of neosynephrine. The size of the pupil on the healthy side was smaller in 65.8% than the pupil on the healthy side. Anisocoria in inner ear lesions is believed to be due to vestibulo-sympathetic imbalance through the superior cervical sympathetic ganglion.

Experimental labyrinthine disorders and direction of nystagmus.

The purpose of this paper is to demonstrate the variation of the direction of nystagmus which is elicited from the peripheral labyrinth. The direction of nystagmus depends, among other things, on the nature of the stimulus. Depending on the degree of pathophysiological conditions in the labyrinth, atypical nystagmus which does not comply with the rule is occasionally elicited even though the same stimulus is given. Hyperfunctional stimulation to the labyrinth, such as allergy, causes nystagmus which beats to the affected side and also shows hyperactivity of the whole nerve action potential and cochlear microphonics.

Findings in the CSF of Patients with Meniere's Diseases

Cerebral Spinal Fluid (CSF) of 22 patients with Menieres disease was examined regarding pressure, number of cells, protein, glucose, and IgA, G, M and E. Almost of all values were within normal limits.There were no differences of each mean value and SD between the irritative and paralytic stage and also between Menieres diseases and labyrinth related syphilis. Regarding the osmolarity of CSF, 5 of 22 patients showed normal values.Other peripheral vestibular lesions (vestibular neuritis, inner ear vertigo due to unknown causes, Ramsey-Hunts syndrome and Vogt-Koyanagi-Haradas disease) were considered to be due to viral infections and immunological disorders.Thus causes of Menieres disease may not be revealed in the CSF, and the inner ear fluid should be examined.