3-Dimentional analysis for the vertical semicircular canal- and the otolithic-ocular reflexes and those influences to the spatial orientation
| Project/Area Number |
10671615
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Tokai University |
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Principal Investigator |
IIDA Masahiro Tokai University, School of Medicine, Associate Professor, 医学部, 助教授 (80184357)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | vertical semicircular canal- ocular reflex / otolithic-ocular reflex / subiective visual vertical (SVV) / 耳石 / 空間識 / 耳石器 / 眼傾斜反応(OTR) |
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| Research Abstract |
Pendular rotation test in a head-tilted position. 60° backward and rotated 45° either to the right or left, was performed in normal healthy subjects and patients with benign paroxysmal positional vertigo (BPPV). They were rotated 360° at the frequency of 0.1 Hz (the maximal speed=114°/sec). We evaluated the excitability of vertical semicircular canals by this test procedure. Using an infra-red CCD camera and a personal computer system, evoked nystagmus was analyzed. When the head was tilted backward in 60°, and then rotated to the right, and with the first pendullar rotation was given to his right, upward and clockwise rotatory nystagmus was seen in all subjects. When the head was rotated 45° to the left, downward, clockwise rotatory nystagmus was seen. With the first pendullar rotation to the left, all nystagmic directions were reversed. It is conceivable that when the head was rotated 45° rightward, upward and clockwise rotatory nystagmus evoked by the rightward rotation was represen
… More
ting excitation of the left posterior semicircular canal, and downward and counterclockwise rotatory nystagmus by the leftward rotation was indicating excitation of the right anterior semicircular canal. When the head was rotated 45° leftward, downward and clockwise rotatory nystagmus by the rightward rotation should represent excitation of the left anterior semicircular canal, and upward and counterclockwise rotatory nystagmus in the leftward rotation indicated excitation of the right posterior semicircular canal. The morbidity of BPPV was determined by analyzing nystagmus elicited by the rotation test. So far as the patients had vertigo, we found a statistically significant difference (P<0.05) in the maximal slow-phase eye velocity (mx SPEV) between nystagmus from the anterior semicircular canal and nystagmus from the posterior semicircular canal. The excitability of the posterior semicircular canal in the affected ear was lower than that of the anterior semicircular canal. Nevertheless. while vertigo and nystagmus disappeared, the difference of the excitability was improved. The present result indicates some functional deterioration of the posterior semicircular canal in BPPV cases, which suggests a mechanical (dumping by mass) and organic (peripheral end organ) participation in causing morbidity. Regarding the present study, in the head tilted forward at an angle of 30° from the upright position, subjective visual vertical (SVV) was normal on the both conditions with and without the rotatory stimulus. It seems that the lateral semicircular canal doesn't influence SVV.On the other hand, SVV was deviated during the posterior canal excited on the condition with the rotatory stimulus, especially, which was much deviated on the opposite side to the excited posterior canal. We conclude that the vertical semicircular canal influences the spatial orientation such as the SVV. Less
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Report
(4 results)
Research Products
(9 results)
