Labyrinthine Reactions and Their Relation to the Clinical Tests

The rapid tilt test has shown that the vertical semicircular canals are in close connexion with the whole postural body musculature. Nystagmus reactions are only a small part of semicircular canal sphere of control. Further knowledge of the reaction-pattern of the body musculature resulting from the stimulation of each semicircular canal will help in diagnosing a lesion, not only of the individual semicircular canals, but also—even more important—of its intracranial connexions. The few reaction patterns already known, but not recognized as such, namely post-pointing, falling, and head turning, are true compensatory reactions, more easily understood if so considered and grouped with the protective reactions to the tilt tests. Recognition of the two modes of utricular action is essential to a correct analysis of tilt test reactions. The slow tilt described by Grahe and others, is an excellent test for “first mode” utricular action, but not for “second mode” action or for vertical semicircular canals. The quick tilt is primarily a test of vertical semicircular canal action, but normally the reaction is complicated by reactions from “second mode” utricular stimulation. If this fact is not taken into account the analysis of a reaction to a quick tilt may be misleading. When performing a quick tilt test, in addition to watching for the absence of the protective reaction (due to loss of one or both labyrinths), the investigator should try to note whether there is a tendency for the patient to be more easily thrown in the direction of the tilt—owing to a lesion of the vertical canals, the utricles being intact (“second mode” utricular action)—or whether there is a tendency for the patient to over-compensate (owing to a lesion of the utricles, the vertical canals being intact). If, in addition to the usual equilibrial tests, the quick tilt test is used in this way and a careful analysis is made of the reactions of patients with labyrinthine or intracranial lesions, diagnosis of lesions of individual labyrinthine end-organs or of their intracranial connexions may become a routine procedure in the clinic just as it is now possible in the laboratory.

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The functional allometry of semicircular canals, fins, and body dimensions in the juvenile centrarchid fish, Lepomis gibbosus (L.)

Development ◽

10.1242/dev.29.3.721 ◽

1973 ◽

Vol 29 (3) ◽

pp. 721-743

Author(s):

Howard C. Howland ◽

Joseph Masci

Keyword(s):

Body Mass ◽

Semicircular Canal ◽

Semicircular Canals ◽

Lepomis Gibbosus ◽

Swimming Velocity ◽

Body Dimensions ◽

Moments Of Inertia ◽

Significant Difference ◽

Vertical Semicircular Canal ◽

Vertical Semicircular Canals

1. The ontogenetic allometry of radii of curvature and the tube radii of the semicircular canals of approximately 85 juvenile (2–20 g) centrarchids of the species Lepomis gibbosus (L.) was investigated. The radii of curvature of the semicircular canals have different allometries; these arefor the anterior vertical, posterior vertical and horizontal canals respectively. The differences in growth exponents between the anterior and posterior vertical semicircular canals and between the anterior vertical and horizontal semicircular canals were statistically significant (P < 0·02 and P < 0·05 respectively). 2. Body mass and standard length were almost equally good predictors of the radii of curvature of the anterior vertical semicircular canals, but body mass was the better predictor of the radii of curvature of the posterior vertical and horizontal semicircular canals, as judged by the magnitude of the mean squares about the logarithmic regressions of radii on length and mass. 3. By measuring and estimating the area moments of the fins of the fish, the moments of inertia about various axes and the allometry of the characteristic swimming velocity of the fish, we attempted to account for the magnitude and direction of the differences in allometric growth exponents of the radii of curvature of the semicircular canals. Unexplained by our best estimate of growth exponents was the very high value observed for the posterior vertical semicircular canals. 4. No significant correlation could be found between the residuals of the major dimensions of the posterior vertical semicircular canals and those of body width or depth once the influence of body mass was removed. This finding suggests the rejection of the hypothesis that the allometry of this semicircular canal is simply correlated with overall body expansion in its plane. 5. The discrepancies between our predictions and observations of growth exponents could be explained by a gradual increase of the spring constant of the semicircular canals on the order ofthough they may also be due to other factors neglected in our model, e.g. the allometry of the added mass of the fish. 6. No evidence suggested that the shape of the semicircular canals was altered over the size range of the fish we studied. However, among the fins of the fish and the major body dimensions, only the width and the depth of the fish exhibited growth constants that did not differ significantly from each other. 7. We computed the effective toroidal radii of the non-toroidal-shaped vertical semicircular canals and found that the equivalent toroidal radius of the anterior vertical semicircular canal was consistently greater than that of the posterior vertical semicircular canal. This difference is explicable on the basis of the different moments of inertia of the animal about axes through the center of gravity and parallel to the axes of the semicircular canals. 8. We computed the allometry of the ratios R̄/r2 for all three semicircular canals and found in accordance with the prediction of Jones & Spells that they did not differ significantly from zero. 9. The allometry of the outer tube radii of the several semicircular canals was determined, and, while there was no significant difference in the growth exponents of the tube radii, it was noted that the tube radius of the horizontal semicircular canal was consistently and significantly smaller than that of the vertical semicircular canal. We suggested that this difference might be due to the broader range of frequencies that the fish experienced about its yaw axis. 10. Taken as a whole the data and calculations of this paper generally support the theory that the dimensions of the semicircular canals and the ontogenetic changes in them attune the semicircular canals to the angular frequency spectra that the fish experience about their axes.

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Semicircular canal and saccular influence on the subjective visual horizontal during gondola centrifugation

Journal of Vestibular Research ◽

10.3233/ves-1999-9504 ◽

1999 ◽

Vol 9 (5) ◽

pp. 347-357

Author(s):

A. Tribukait

Keyword(s):

Semicircular Canal ◽

Semicircular Canals ◽

Central Position ◽

Otolith Organs ◽

Force Vector ◽

Time Constants ◽

Storage Mechanism ◽

Spatial Disorientation ◽

Gravitoinertial Force ◽

Vertical Semicircular Canals

Measurements of the subjective visual horizontal (SVH) were performed in 11 healthy test persons during an increase of the resultant gravitoinertial force vector in a large swing-out gondola centrifuge. Three levels of hypergravity (1.5g, 2.0g, 2.5g) were used, each with a duration of 4 minutes and with 1–2 minute pauses at 1.0g in between. The direction of the resultant gravitoinertial force vector was always parallel with the head and body length axis. Hence, there was no roll stimulus to the otolith organs. The swing-out of the gondola during acceleration, however, is sensed by the vertical semicircular canals as a change in roll head position, thus creating an otolith-semicircular canal conflict. After acceleration of the centrifuge there was a tilt of the SVH relative to the resultant gravitoinertial horizontal. This tilt gradually decayed during the 4-minute period of recordings. For a subgroup of seven test subjects who had completely normal ENG-recordings in 1g environment, the initial offset of SVH and the time constants for exponential decay were determined for each g level; initial offsets: 9 . 9 ∘ (1.5g), 7 . 7 ∘ (2.0g), 6 . 1 ∘ (2.5g); time constants: 89s (1.5g), 74s (2.0g), 37s (2.5g). The offset of SVH is interpreted as being the result of mainly the stimulus to the vertical semicircular canals during acceleration of the centrifuge. The slow decay, however, does not correspond to the dynamics of the semicircular canal system, and is suggested to reflect some kind of central position storage mechanism. A smaller offset and more rapid decay for the higher g loads may be explained by an increasing dominance of graviceptive input, presumably from the saccules. In conclusion, these results might suggest the role of the vertical semicircular canals as well as the sacculus in the formation of SVH. They may also have relevance with regard to the spatial disorientation problem in aviators.

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Pulsed Infrared Stimulation of Vertical Semicircular Canals Evokes Cardiovascular Changes in the Rat

Frontiers in Neurology ◽

10.3389/fneur.2021.680044 ◽

2021 ◽

Vol 12 ◽

Author(s):

Darrian Rice ◽

Giorgio P. Martinelli ◽

Weitao Jiang ◽

Gay R. Holstein ◽

Suhrud M. Rajguru

Keyword(s):

Heart Rate ◽

Nervous System ◽

Semicircular Canal ◽

Parasympathetic Nervous System ◽

Semicircular Canals ◽

Whole Body ◽

Experimental Session ◽

Otolith Organs ◽

Vertical Semicircular Canals ◽

Stimulation Of

A variety of stimuli activating vestibular end organs, including sinusoidal galvanic vestibular stimulation, whole body rotation and tilt, and head flexion have been shown to evoke significant changes in blood pressure (BP) and heart rate (HR). While a role for the vertical semicircular canals in altering autonomic activity has been hypothesized, studies to-date attribute the evoked BP and HR responses to the otolith organs. The present study determined whether unilateral activation of the posterior (PC) or anterior (AC) semicircular canal is sufficient to elicit changes in BP and/or HR. The study employed frequency-modulated pulsed infrared radiation (IR: 1,863 nm) directed via optical fibers to PC or AC of adult male Long-Evans rats. BP and HR changes were detected using a small-animal single pressure telemetry device implanted in the femoral artery. Eye movements evoked during IR of the vestibular endorgans were used to confirm the stimulation site. We found that sinusoidal IR delivered to either PC or AC elicited a rapid decrease in BP and HR followed by a stimulation frequency-matched modulation. The magnitude of the initial decrements in HR and BP did not correlate with the energy of the suprathreshold stimulus. This response pattern was consistent across multiple trials within an experimental session, replicable, and in most animals showed no evidence of habituation or an additive effect. Frequency modulated electrical current delivered to the PC and IR stimulation of the AC, caused decrements in HR and BP that resembled those evoked by IR of the PC. Frequency domain heart rate variability assessment revealed that, in most subjects, IR stimulation increased the low frequency (LF) component and decreased the high frequency (HF) component, resulting in an increase in the LF/HF ratio. This ratio estimates the relative contributions of sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) activities. An injection of atropine, a muscarinic cholinergic receptor antagonist, diminished the IR evoked changes in HR, while the non-selective beta blocker propranolol eliminated changes in both HR and BP. This study provides direct evidence that activation of a single vertical semicircular canal is sufficient to activate and modulate central pathways that control HR and BP.

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vHIT Testing of Vertical Semicircular Canals With Goggles Yield Different Results Depending on Which Canal Plane Being Tested

Frontiers in Neurology ◽

10.3389/fneur.2021.692196 ◽

2021 ◽

Vol 12 ◽

Author(s):

Louise Wittmeyer Cedervall ◽

Måns Magnusson ◽

Mikael Karlberg ◽

Per-Anders Fransson ◽

Anastasia Nyström ◽

...

Keyword(s):

Semicircular Canal ◽

Vestibular Function ◽

Vertical Direction ◽

Semicircular Canals ◽

Vertical Movement ◽

Head Impulse Test ◽

Recording Device ◽

Prospective Design ◽

Vertical Semicircular Canal ◽

Vertical Semicircular Canals

Objective: The use of goggles to assess vertical semicircular canal function has become a standard method in vestibular testing, both in clinic and in research, but there are different methods and apparatus in use. The aim of this study was to determine what the cause of the systematic differences is between gain values in testing of the vertical semicircular canals with two different video head impulse test (vHIT) equipment in subjects with normal vestibular function.Study Design: Retrospective analysis of gain values on patients with clinically deemed normal vestibular function (absence of a corrective eye saccade), tested with either Interacoustics or Otometrics system. Prospective testing of subjects with normal vestibular function with the camera records the eye movements of both eyes. Finally, 3D sensors were placed on different positions on the goggles measuring the actual vertical movement in the different semicircular planes.Results: In the clinical cohorts, the gain depended on which side and semicircular canal was tested (p < 0.001). In the prospective design, the combination between the stimulated side, semicircular canal, and position of the recording device (right/left eye) highly influenced the derived gain (p < 0.001). The different parts of the goggles also moved differently in a vertical direction during vertical semicircular canal testing.Conclusion: The gain values when testing the function of the vertical semicircular canals seem to depend upon which eye is recorded and which semicircular plane is tested and suggests caution when interpreting and comparing results when different systems are used both clinically as well as in research. The results also imply that further research and development are needed to obtain accurate vertical semicircular canal testing, in regard to both methodology and equipment design.

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Automatic Measurement of Inner Ear in Different Mammals1

10.1101/2020.09.30.317941 ◽

2020 ◽

Author(s):

Yi Du ◽

Han-dai Qin ◽

Chen Liu ◽

Da Liu ◽

Shuo-long Yuan ◽

...

Keyword(s):

Inner Ear ◽

Semicircular Canal ◽

Three Dimensional ◽

Semicircular Canals ◽

Automatic Measurement ◽

The Body ◽

Human Data ◽

Dimensional Models ◽

Three Dimensional Models ◽

Mini Pigs

AbstractObjectiveThe aim of this research is to develop an accurate and automatic measuring method based on the aid of centerline to construct three dimensional models of inner ear in different mammals and to assess the morphological variations.MethodsThree adult healthy mice, three adult guinea pigs, three adult mini pigs and one left temporal bone of human were included in this research. All 18 animal specimens and the human sample were scanned with the use of Micro-CT. After being segmented, three-dimensional models of the inner ear in different mammals were reconstructed using Mimics. A novel method with the use of centerline was established to estimate the properties of 3D models and to calculate the length, volume and angle parameters automatically.ResultsMorphological models of inner ears in different mammals have been built, which describe detailed shape of cochlear, vestibule, semicircular canals and common crus. Mean value of lengths and volumes of the cochlear, lateral semicircular canal, superior semicircular canal and posterior semicircular canal, tended to increase with the body size of the mammals, showed the proximity to the human data in mini pig. The angles between the semicircular canal planes showed differences between mammals. The mean values of semicircular canals of mice and mini pigs closely resembled to human data in numerical assessment.ConclusionThe automatic measurement of the inner ear based on centerline builds an effective way to assess lengths, volumes and angles of three-dimensional structures. This study provides a theoretical basis for mechanical analysis of inner ear in different mammals and proves the similarity between mini pig and human.

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The Dimensions and Sensitivities of Semicircular Canals

Journal of Experimental Biology ◽

10.1242/jeb.53.2.501 ◽

1970 ◽

Vol 53 (2) ◽

pp. 501-514

Author(s):

J. H. TEN KATE ◽

H. H. VAN BARNEVELD ◽

J. W. KUIPER

Keyword(s):

Growth Rate ◽

Body Mass ◽

Semicircular Canal ◽

Semicircular Canals ◽

The Body ◽

Horizontal Semicircular Canal ◽

Order Of Magnitude ◽

Allometric Functions ◽

Special Growth ◽

Narrow Duct

1. The dimensions of the semicircular canals of pike can be expressed as allometric functions of the body length L. 2. The equal sensitivity of pike of different sizes to rotatory stimulation can be explained as a quadratic bending of the cupula. 3. In the pike the sensitivity is of the same order of magnitude for the vertical and horizontal semicircular canals. 4. In the pike the growth rate of the volumes of duct and ampulla is the same for the horizontal semicircular canal and for the posterior semicircular canal. 5. The special growth rate of the dimensions of the horizontal semicircular canal of the ray can be explained by a quadratic bending of the cupula. 6. For equally large cupulae the sensitivity of the horizontal semicircular canal is of the same order of magnitude for twenty-three mammals, fourteen birds and one reptile as it is for the pike. 7. Within the limits of error the ‘growth rate’ of the diameter of the narrow duct is the same in mammals as in the pike. 8. At the same body mass the absolute value of the diameter of the narrow duct is smaller in mammals than in the pike by a factor of 1.69. 9. For a body mass of 1 kg the value of the enclosed area of the horizontal semicircular canal is 6 times smaller in mammals than in pike. 10. The model of the overcritically damped oscillator for the semicircular canal remains valid during growth if a quadratic bending of the cupula is assumed.

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Unilateral Multicanalicular Vestibular Lithiasis of Right Horizontal and Posterior Semicircular Canals: An Unusual Case

Annals of Otology and Neurotology ◽

10.1055/s-0041-1735989 ◽

2021 ◽

Author(s):

Ajay Kumar Vats

Keyword(s):

Semicircular Canal ◽

Unusual Case ◽

Semicircular Canals ◽

Posterior Semicircular Canal ◽

Gelatinous Matrix ◽

History Of ◽

Head Roll ◽

The Individual ◽

Treatment Priorities ◽

Torsional Nystagmus

AbstractVestibular lithiasis (canalolithiasis as well as cupulolithiasis) commonly exists in monocanalicular forms involving one of the three semicircular canals, frequent posterior, less frequent horizontal, and very rarely anterior. It is treated with canal clearing maneuvers intended to reposition the otoconia from the semicircular canal (where they have inappropriately entered) through the utricular exit in the nonampullary arm of the semicircular canal to the utricle (where they normally remain as a part of utricular gelatinous matrix). The cases of multicanalicular vestibular lithiasis with the involvement of more than one semicircular canal require meticulous identification of the involved canals and multiple different canal-clearing maneuvers for effective treatment. A 70-year-old male patient with no significant history of previous medical or otologic illnesses or head trauma presented with a 1-day history of vertigo with positional aggravation. A one-time performed diagnostic supine head roll test elicited three different patterns of positional nystagmus, each with an accurate localizing and lateralizing value. Diagnosis of unilateral multicanalicular vestibular lithiasis of right horizontal and posterior semicircular canals was entertained based on the pattern of the elicited positional nystagmi on the supine roll test. The upbeating torsional nystagmus that localizes the involvement to the posterior semicircular canal was paradoxically elicited by supine head roll test and not by the Dix–Hallpike test. As horizontal semicircular canalolithiasis causes severe symptoms, its treatment preceded that of concurrent posterior semicircular canalolithiasis. The patient was successfully treated with multiple sessions of canalith repositioning maneuvers (CRMs) spread over 24 hours. It is important to perform both positional tests, namely Dix–Hallpike maneuver, and supine head roll test, in cases suspected to have multicanalicular vestibular lithiasis. The positionings may need to be repeated several times to unveil multiple nystagmi, each with different localizing and lateralizing values. Identifying treatment priorities with CRM for the individual semicircular canals is crucial, and the canal that is liable to cause severe symptoms needs early clearance of the otoconial debris. If a CRM fails to clear a semicircular canal, an alternative maneuver may need to be executed. Clinicians involved in the care of cases with multicanalicular vestibular lithiasis should be well versed with all possible backup maneuvers for clearing each of the three semicircular canals.

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Central Versus Peripheral Origin of Vestibuloocular Reflex Recovery Following Semicircular Canal Plugging in Rhesus Monkeys

Journal of Neurophysiology ◽

10.1152/jn.2000.84.6.3078 ◽

2000 ◽

Vol 84 (6) ◽

pp. 3078-3082 ◽

Cited By ~ 19

Author(s):

Bernhard J. M. Hess ◽

Anna Lysakowski ◽

Lloyd B. Minor ◽

Dora E. Angelaki

Keyword(s):

Semicircular Canal ◽

Rhesus Monkeys ◽

Semicircular Canals ◽

Vestibuloocular Reflex ◽

Head Acceleration ◽

Significant Recovery ◽

Sinusoidal Oscillations ◽

Vertical Semicircular Canals ◽

Peripheral Origin

We have previously shown that there is a slowly progressing, frequency-specific recovery of the gain and phase of the horizontal vestibuloocular reflex (VOR) in rhesus monkeys following plugging of the lateral semicircular canals. The adapted VOR response exhibited both dynamic and spatial characteristics that were distinctly different from responses in intact animals. To discriminate between adaptation or recovery of central versus peripheral origin, we have tested the recovered vestibuloocular responses in three rhesus monkeys in which either one or both coplanar pairs of vertical semicircular canals had been plugged previously by occluding the remaining semicircular canals in a second plugging operation. We measured the spatial tuning of the VOR in two or three different mutually orthogonal planes in response to sinusoidal oscillations (1.1 Hz, ±5°, ±35°/s) over a period of 2–3 and 12–14 mo after each operation. Apart from a significant recovery of the torsional/vertical VOR following the first operation we found that these recovered responses were preserved following the second operation, whereas the responses from the newly operated semicircular canals disappeared acutely as expected. In the follow-up period of up to 3 mo after the second operation, responses from the last operated canals showed recovery in two of three animals, whereas the previously recovered responses persisted. The results suggest that VOR recovery following plugging may depend on a regained residual sensitivity of the plugged semicircular canals to angular head acceleration.

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Automatic Semicircular Canal Segmentation of CT Volumes Using Improved 3D U-Net with Attention Mechanism

Computational Intelligence and Neuroscience ◽

10.1155/2021/9654059 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Hongcheng Wu ◽

Juanxiu Liu ◽

Gui Chen ◽

Weixing Liu ◽

Ruqian Hao ◽

...

Keyword(s):

Vestibular System ◽

Semicircular Canal ◽

Network Performance ◽

Semicircular Canals ◽

Attention Mechanism ◽

The Body ◽

Test Dataset ◽

Tomography Image ◽

Segmentation Task ◽

Computed Tomography Image

The vestibular system is the sensory apparatus that helps the body maintain its postural equilibrium, and semicircular canal is an important organ of the vestibular system. The semicircular canals are three membranous tubes, each forming approximately two-thirds of a circle with a diameter of approximately 6.5 mm, and segmenting them accurately is of great benefit for auxiliary diagnosis, surgery, and treatment of vestibular disease. However, the semicircular canal has small volume, which accounts for less than 1% of the overall computed tomography image. Doctors have to annotate the image in a slice-by-slice manner, which is time-consuming and labor-intensive. To solve this problem, we propose a novel 3D convolutional neural network based on 3D U-Net to automatically segment the semicircular canal. We added the spatial attention mechanism of 3D spatial squeeze and excitation modules, as well as channel attention mechanism of 3D global attention upsample modules to improve the network performance. Our network achieved an average dice coefficient of 92.5% on the test dataset, which shows competitive performance in semicircular canals segmentation task.

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Influence of stable iodine on the uptake of the thyroid – model vs. experiment

Nuklearmedizin ◽

10.1055/s-0038-1623989 ◽

2001 ◽

Vol 40 (01) ◽

pp. 31-37 ◽

Cited By ~ 1

Author(s):

U. Wellner ◽

E. Voth ◽

H. Schicha ◽

K. Weber

Keyword(s):

Time Course ◽

Compartment Model ◽

The Body ◽

Iodine Uptake ◽

Model Calculations ◽

Physiological Conditions ◽

Iodine Supply ◽

Predicted Values ◽

The Individual ◽

Stable Iodine

Summary Aim: The influence of physiological and pharmacological amounts of iodine on the uptake of radioiodine in the thyroid was examined in a 4-compartment model. This model allows equations to be derived describing the distribution of tracer iodine as a function of time. The aim of the study was to compare the predictions of the model with experimental data. Methods: Five euthyroid persons received stable iodine (200 μg, 10 mg). 1-123-uptake into the thyroid was measured with the Nal (Tl)-detector of a body counter under physiological conditions and after application of each dose of additional iodine. Actual measurements and predicted values were compared, taking into account the individual iodine supply as estimated from the thyroid uptake under physiological conditions and data from the literature. Results: Thyroid iodine uptake decreased from 80% under physiological conditions to 50% in individuals with very low iodine supply (15 μg/d) (n = 2). The uptake calculated from the model was 36%. Iodine uptake into the thyroid did not decrease in individuals with typical iodine supply, i.e. for Cologne 65-85 μg/d (n = 3). After application of 10 mg of stable iodine, uptake into the thyroid decreased in all individuals to about 5%, in accordance with the model calculations. Conclusion: Comparison of theoretical predictions with the measured values demonstrated that the model tested is well suited for describing the time course of iodine distribution and uptake within the body. It can now be used to study aspects of iodine metabolism relevant to the pharmacological administration of iodine which cannot be investigated experimentally in humans for ethical and technical reasons.

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