There are two methods for measurement of eye position in three dimensions. One is the scleral search coil technique and the other is video-oculography (VOG). Although the VOG system is not as accurate as the scleral search coil system in the ability of time and space resolution, it is suitable for clinical use. There are two types of VOG system: One for analysis using Fick coordinates, and the other for analysis using axis angle, rotation vector and quaternions. Fick coordinate analysis measures three consecutive rotations about the horizontal, vertical, and torsional eye-fixed axes. Axis angle, rotation vector and quaternions measure single axis rotation from a chosen reference position to the current eye position. The system for analyzing by Fick coordinates utilizes the movement of the center of the pupil in order to calculate horizontal and vertical eye movement. In order to calculate the torsional component, the system uses the movement of an iris freckle or iris pattern. The system for analyzing axis angle, rotation vector and quaternions reconstructs the three-dimensional coordinates of the center of the pupil and an iris freckle in space. From these movements in space, the system calculates axis angle, rotation vector and quarternions. In this review, such two type of VOG systems are introduced, and the advantages and disadvantages of both types are discussed.
It is known that abnormality in the autonomic nervous system often induces dizziness, and standing position tests including the Schellong test (ST) and head up tilt test (HUT) have been used for diagnosis. HUT is often used for the diagnosis of vasovagal reflex (VVR), a dizziness disease caused by the abnormality in autonomic nervous system, but there are few reports that compared the results of ST and HUT in VVR patients. We conducted ST and HUT in 6 patients with VVR-related dizziness, and compared the results. Six patients were studied including 3 males and 3 females with a mean age of 25.5 years of age who visited the otolaryngology department of Juntendo Izu-Nagaoka Hospital and Juntendo Urayasu Hospital and were diagnosed with dizziness caused by VVR. These 6 patients with dizziness underwent ST and HUT tests in the standing position, to compare their test results. The assessment variables were cardiac rate, systolic blood pressure, and diastolic blood pressure. The results of ST were negative in all 6 patients, however, those of HUT were positive in 5 patients. In comparison of cardiac rates at rest, mean cardiac rate in ST was 72.6±9.6 beats/min without statistically significant difference compared with 67.8±13.9 beats/min in HUT. On the other hand, in comparison of cardiac rates at rest and immediately after head up, mean cardiac rate immediately after head up in ST was 82.7±10.7 beats/min with significant difference, while mean cardiac rate after head up in HUT was 87.3±10.8 beats/min and increased with significant difference compared with the baseline at rest. Increase in cardiac rates in one of the factors that induces vasovagal reflex. Head up tilt test might easily induce vasovagal reflex, as cardiac rate promptly increases immediately after head up.
In mammals, the loss of vestibular hair cells appears to lead to limited proliferation of supporting cells in vivo.However, recent studies have indicated that active cell proliferation can be induced by brief exposure to forskolin in cultured utricles using the seat culture technique. The aim of this study was to examine whether such cell proliferation in vestibular epithelia could be induced using the standard organ culture. Utricles harvested from Wistar rats at 3 days of age were provided for organ culture. After brief incubation in a medium containing forskolin, utricles were maintained in medium containing fetal bovine serum and bromodeoxyuridine (BrdU) for 72 hrs. Immunohistochemistry for BrdU demonstrated the localization of BrdU-positive cells in cultured utricles, but their number was apparently smaller than that in the study with seat culture reported previously. In addition, only 10% of comprehensive BrdU-positive cells were located within the sensory epithelium. Therefore, the cell proliferation activity in the vestibular epithelium using organ culture differed from that using seat culture, although mammalian vestibular epithelia have the potential for cell proliferation. Elucidating what causes the difference in cell proliferation between organ culture and seat culture will lead to establishment of a strategy for induction of activity cell proliferation in mammalian vestibular hair cells in vivo.
Apogeotropic direction-changing positional nystagmus has been considered to indicate central lesions, Nystagmus as has a proportion of geotropic direction-changing positional nystagmus, appears in patients with both peripheral and central lesions. However, it has been clarified that peripheral lesions more frequently show apogeotropic and geotropic nystagmus as the reports about direction-changing positional nystagmus have increased in recent years. This study was designed to investigate the clinical features of direction-changing positional nystagmus, including paroxysmal positional nystagmus. One hundred and fifty-two patients (60 males and 92 females) diagnosed as having direction-changing positional nystagmus were examined using an infrared CCD camera. Seventy patients were diagnosed as having apogeotropic direction-changing positional nystagmus. They were 30 males and 40 females aged from 22 to 82 years, with an average age of 60.2. The etiological diagnoses of these patients were 42 cases (60.0%) of peripheral lesions, 26 cases (37.1%) of central lesions, and 2 cases of unknown origin. Eighty-two patients were diagnosed as having geotropic direction-changing positional nystagmus. They were 30 males and 52 females aged from 20 to 89 years, with an average age of 55.9. The etiological diagnoses of these patients were 57 cases (69.5%) of peripheral lesions, 19 cases (23.2%) of central lesions, and 6 cases of unknown origin. The pattern of peripheral nystagmus showed great variety and inconsistency, suggesting difficulty in differentiating peripheral from central lesions simply from nystagmus test at the first consultation.
The passage of time of equilibrium research in Japan was described from the early stage of the study of this field to the organization of the Japan Society of Equilibrium Research (JSER). Vestibular research (VR) in Japan originated with I. Kubo, T. Hosino and K. Yamakawa in the early 20th century. After the end of World War II (1945), VR in Japan was restored. Meniere's disease, motion sickness, human dynamic posture, rotation and caloric reactions, neuro-otological diagnosis of the central disturbances, optokinetic vertigo and ataxia, visual-vestibular coordination and functional development of labyrinthine function with rotatory training were studied actively. The meeting of VR was established in 1957, and in 1962, the meeting name was changed to the Japan Society of VR. In these periods, morphological and electrophysiological investigations on the vestibular organ as well as studies on vestibular examination, Meniere's disease and space motion sickness were carried out. In 1960, standardization of vestibular examinations was advocated. In 1968, the society changed its name to the Japan Society for Equilibrium Research (JSER) from the viewpoint that vestibular function should be investigated in relation to optic and proprioceptive equilibrium function.