Vestibular Function in the Fetal Sheep

1998 ◽  
Vol 118 (5) ◽  
pp. 571-575
Author(s):  
Patrick J. Antonelli ◽  
Robert M. Abrams ◽  
Kenneth J. Gerhardt ◽  
Matthias Schwab ◽  
Reinhard Bauer
Keyword(s):  
Body Temperature ◽  
Vestibular System ◽  
Cold Water ◽  
Fetal Brain ◽  
Vestibular Function ◽  
Brain Maturation ◽  
Slow Phase ◽  
Facial Skin ◽  
Fetal Sheep ◽  
Caloric Stimulation

Little is known about the functional development of the vestibular system before birth. The purpose of this study was to determine whether vestibular response to caloric stimulation could be elicited in the fetal sheep in utero. Late gestational fetal sheep ( n = 6) were instrumented through a midline hysterotomy. Copper caloric probes were inserted into the right bulla and beneath the left facial skin. Electrodes were placed in the skull for monitoring of electro-ocular activity. At least 3 days after surgery the probes were irrigated with water (100 ml/minute) at body temperature, 46° C, and 6° C. Cold water infusion of the bulla consistently produced well-recognized, slow-phase deviations followed by saccades directed contralaterally, findings consistent with vestibular nystagmus. The direction of the response reversed with warm water irrigation. The response was absent with irrigation at fetal body temperature. Only random eye movements were observed in response to caloric stimulation of the facial skin, regardless of water temperature. These results demonstrate that the sheep vestibular system is functioning prenatally. The importance of vestibular function for normal fetal brain maturation may be revealed in future studies using this animal model. (Otolaryngol Head Neck Surg 1998;118:571–5.)

Caloric response does not decline with age

2004 ◽  
Vol 14 (5) ◽  
pp. 393-396
Author(s):  
A.I. Mallinson ◽  
N.S. Longridge
Keyword(s):  
Vestibular System ◽  
Vestibular Function ◽  
The Elderly ◽  
Slow Phase ◽  
Balance System ◽  
Age Related ◽  
Dependent Change ◽  
Physiologic Function ◽  
Caloric Response ◽  
Anatomical Evidence

Complaints of imbalance in the elderly are commonly heard by clinicians, and pathology of the vestibular system may play an important role in these complaints. While there is solid anatomical evidence for age related decline of some vestibular structures, a corresponding deterioration in physiologic function has not been convincingly demonstrated. Vestibular function is traditionally measured with caloric irrigations. Although there has been some age dependent change in caloric response shown, there is no good parallel between caloric response and imbalance in the elderly patient. Our experiment confirms that slow phase velocity of caloric responses does not decline with age. Calorics measure only one part of the vestibular system, and so should not be regarded as representative of balance system function. As a result, measured caloric response does not parallel documented anatomic age-related decline of the vestibular system.

Vestibular Function and Motion Sickness Susceptibility: Videonystagmographic Evidence From Oculomotor and Caloric Tests

2020 ◽  
Vol 29 (2) ◽  
pp. 188-198
Author(s):  
Cynthia G. Fowler ◽  
Margaret Dallapiazza ◽  
Kathleen Talbot Hadsell
Keyword(s):  
Phase Velocity ◽  
Motion Sickness ◽  
Repeated Measures ◽  
Short Form ◽  
Vestibular Function ◽  
Slow Phase ◽  
Test Results ◽  
Normal Range ◽  
Slow Phase Velocity ◽  
Caloric Tests

Purpose Motion sickness (MS) is a common condition that affects millions of individuals. Although the condition is common and can be debilitating, little research has focused on the vestibular function associated with susceptibility to MS. One causal theory of MS is an asymmetry of vestibular function within or between ears. The purposes of this study, therefore, were (a) to determine if the vestibular system (oculomotor and caloric tests) in videonystagmography (VNG) is associated with susceptibility to MS and (b) to determine if these tests support the theory of an asymmetry between ears associated with MS susceptibility. Method VNG was used to measure oculomotor and caloric responses. Fifty young adults were recruited; 50 completed the oculomotor tests, and 31 completed the four caloric irrigations. MS susceptibility was evaluated with the Motion Sickness Susceptibility Questionnaire–Short Form; in this study, percent susceptibility ranged from 0% to 100% in the participants. Participants were divided into three susceptibility groups (Low, Mid, and High). Repeated-measures analyses of variance and pairwise comparisons determined significance among the groups on the VNG test results. Results Oculomotor test results revealed no significant differences among the MS susceptibility groups. Caloric stimuli elicited responses that were correlated positively with susceptibility to MS. Slow-phase velocity was slowest in the Low MS group compared to the Mid and High groups. There was no significant asymmetry between ears in any of the groups. Conclusions MS susceptibility was significantly and positively correlated with caloric slow-phase velocity. Although asymmetries between ears are purported to be associated with MS, asymmetries were not evident. Susceptibility to MS may contribute to interindividual variability of caloric responses within the normal range.

scholarly journals Human thermoregulatory responses during serial cold-water immersions

1998 ◽  
Vol 85 (1) ◽  
pp. 204-209 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
Michael N. Sawka ◽  
Kent B. Pandolf
Keyword(s):  
Body Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Alternative Explanation ◽  
Cold Water ◽  
Metabolic Heat Production ◽  
Normal Body Temperature ◽  
Repeat Trial ◽  
Metabolic Heat ◽  
Made In

This study examined whether serial cold-water immersions over a 10-h period would lead to fatigue of shivering and vasoconstriction. Eight men were immersed (2 h) in 20°C water three times (0700, 1100, and 1500) in 1 day (Repeat). This trial was compared with single immersions (Control) conducted at the same times of day. Before Repeat exposures at 1100 and 1500, rewarming was employed to standardize initial rectal temperature. The following observations were made in the Repeat relative to the Control trial: 1) rectal temperature was lower and heat debt was higher ( P < 0.05) at 1100; 2) metabolic heat production was lower ( P < 0.05) at 1100 and 1500; 3) subjects perceived the Repeat trial as warmer at 1100. These data suggest that repeated cold exposures may impair the ability to maintain normal body temperature because of a blunting of metabolic heat production, perhaps reflecting a fatigue mechanism. An alternative explanation is that shivering habituation develops rapidly during serially repeated cold exposures.

CLASSIFICATION OF HUMAN FACIAL AND AURAL TEMPERATURE USING NEURAL NETWORKS AND IR FEVER SCANNER: A RESPONSIBLE SECOND LOOK

2005 ◽  
Vol 05 (01) ◽  
pp. 165-190 ◽  
Author(s):  
E. Y. K. NG ◽  
COLIN CHONG ◽  
G. J. L. KAW
Keyword(s):  
Neural Network ◽  
Body Temperature ◽  
False Negative ◽  
The Body ◽  
Body Core Temperature ◽  
Thermal Imager ◽  
Facial Skin ◽  
Thermal Imagers ◽  
Cardinal Symptom ◽  
Elevated Body Temperature

Severe Acute Respiratory Syndrome (SARS) is a highly infectious disease caused by a coronavirus. Screening to detect potential SARS infected subject with elevated body temperature plays an important role in preventing the spread of SARS. The use of infrared (IR) thermal imaging cameras has thus been proposed as a non-invasive, speedy, cost-effective and fairly accurate means for mass blind screening of potential SARS infected persons. Infrared thermography provides a digital image showing temperature patterns. This has been previously utilized in the detection of inflammation and nerve dysfunctions. It is believed that IR cameras may potentially be used to detect subjects with fever, the cardinal symptom of SARS and avian influenza. The accuracy of the infrared system can, however, be affected by human, environmental, and equipment variables. It is also limited by the fact that the thermal imager measures the skin temperature and not the body core temperature. Thus, the use of IR thermal systems at various checkpoints for mass screening of febrile persons is scientifically unjustified such as what is the false negative rate and most importantly not to create false sense of security. This paper aims to study the effectiveness of infrared systems for its application in mass blind screening to detect subjects with elevated body temperature. For this application, it is critical for thermal imagers to be able to identify febrile from normal subjects accurately. Minimizing the number of false positive and false negative cases improves the efficiency of the screening stations. False negative results should be avoided at all costs, as letting a SARS infected person through the screening process may result in potentially catastrophic results. Hitherto, there is lack of empirical data in correlating facial skin with body temperature. The current work evaluates the correlations (and classification) between the facial skin temperatures to the aural temperature using the artificial neural network approach to confirm the suitability of the thermal imagers for human temperature screening. We show that the Train Back Propagation and Kohonen self-organizing map (SOM) can form an opinion about the type of network that is better to complement thermogram technology in fever diagnosis to drive a better parameters for reducing the size of the neural network classifier while maintaining good classification accuracy.

Monocular Nystagmic Responses to Caloric Stimulation

1979 ◽  
Vol 88 (1) ◽  
pp. 79-85 ◽  
Author(s):  
James W. Wolfe
Keyword(s):  
Phase Velocity ◽  
Rhesus Monkeys ◽  
Cold Water ◽  
Normal Subjects ◽  
Closed Circuit ◽  
Slow Phase ◽  
Vestibular Nystagmus ◽  
Differential Activation ◽  
Slow Phase Velocity ◽  
Left And Right

Twenty-five normal subjects and 173 clinical patients received standard bithermal caloric testing. Vestibular nystagmus was evaluated for cumulative slow phase velocity from the summated horizontal eye recording and independent recording of the left and right eye. These data revealed that cold water stimulation produced more intense activation of the ipsilateral eye. Simultaneous closed-circuit video and D.C. electro-oculographic recordings from eight normal rhesus monkeys in response to cold water irrigations confirmed the fact that this stimulus leads to differential activation of the extraocular muscles. A possible explanation for this finding is discussed.

scholarly journals Effect of Drinking Hot or Cold Water and Intaking Hot Meal on the Body Temperature Measured by Ear Drum. Meaning of ONPUKU.

1994 ◽  
Vol 44 (4) ◽  
pp. 583-587
Author(s):  
Minoru HIGASA ◽  
Iwao YAMAMOTO ◽  
Ichiro NARIKAWA
Keyword(s):  
Body Temperature ◽  
Cold Water ◽  
The Body

Heat production of fetal sheep brain in utero

1977 ◽  
Vol 43 (4) ◽  
pp. 747-749 ◽  
Author(s):  
R. M. Abrams ◽  
J. F. Clapp ◽  
M. Notelovitz ◽  
T. Tyler ◽  
S. Cassin
Keyword(s):  
Specific Heat ◽  
Heat Production ◽  
Brain Temperature ◽  
Main Pulmonary Artery ◽  
Fetal Brain ◽  
In Utero ◽  
Total Occlusion ◽  
Fetal Sheep ◽  
Sheep Brain ◽  
Near Term

Thermojunctions were implanted in the brains of 10 near term fetal sheep in utero under halothane anesthesia. Brief total occlusion of fetal brachiocephalic artery was followed immediately by an increase in brain temperature (mean +/- SE) of 0.130 +/- 0.014 degrees C-min-1. Occlusion of main pulmonary artery and ascending aorta, simultaneously, led to a brain temperature increase of 0.144 +/- 0.018 degrees C-min-1. Specific heat of three fetal brains was determined to be 0.898 +/- 0.014 cal-g-1. degrees C-1 or 3.76 +/- 0.059 J-g-1. Rate of fetal brain heat production, computed as the product of the higher rate of temperature change and brain specific heat, was 0.129 +/- 0.014 cal-g-1-min-1 or 9.00 +/- 0.98 mW-g-1.

scholarly journals Direct comparison between apparent diffusion coefficient and macromolecular proton fraction as quantitative biomarkers of the human fetal brain maturation

2019 ◽  
Vol 50 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Alexandra M. Korostyshevskaya ◽  
Irina Yu. Prihod'ko ◽  
Andrey A. Savelov ◽  
Vasily L. Yarnykh
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Fetal Brain ◽  
Brain Maturation ◽  
Human Fetal Brain ◽  
Apparent Diffusion

scholarly journals Finding a Balance: A Systematic Review of the Biomechanical Effects of Vestibular Prostheses on Stability in Humans

2020 ◽  
Vol 5 (2) ◽  
pp. 23
Author(s):  
Felix Haxby ◽  
Mohammad Akrami ◽  
Reza Zamani
Keyword(s):  
Vestibular System ◽  
Postural Sway ◽  
Vestibular Function ◽  
Vestibular Stimulation ◽  
Significant Heterogeneity ◽  
Vestibular Loss ◽  
Ocular Reflex ◽  
Gait Characteristics ◽  
Vestibulo Ocular Reflex ◽  
Meta Analyses

The vestibular system is located in the inner ear and is responsible for maintaining balance in humans. Bilateral vestibular dysfunction (BVD) is a disorder that adversely affects vestibular function. This results in symptoms such as postural imbalance and vertigo, increasing the incidence of falls and worsening quality of life. Current therapeutic options are often ineffective, with a focus on symptom management. Artificial stimulation of the vestibular system, via a vestibular prosthesis, is a technique being explored to restore vestibular function. This review systematically searched for literature that reported the effect of artificial vestibular stimulation on human behaviours related to balance, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) technique. A total of 21 papers matched the inclusion criteria of the literature search conducted using the PubMed and Web of Science databases (February 2019). The populations for these studies included both healthy adults and patients with BVD. In every paper, artificial vestibular stimulation caused an improvement in certain behaviours related to balance, although the extent of the effect varied greatly. Various behaviours were measured such as the vestibulo-ocular reflex, postural sway and certain gait characteristics. Two classes of prosthesis were evaluated and both showed a significant improvement in at least one aspect of balance-related behaviour in every paper included. No adverse effects were reported for prostheses using noisy galvanic vestibular stimulation, however, prosthetic implantation sometimes caused hearing or vestibular loss. Significant heterogeneity in methodology, study population and disease aetiology were observed. The present study confirms the feasibility of vestibular implants in humans for restoring balance in controlled conditions, but more research needs to be conducted to determine their effects on balance in non-clinical settings.

Dual core and shell temperature regulation during sea acclimatization in Gentoo penguins (Pygoscelis papua)

1994 ◽  
Vol 266 (4) ◽  
pp. R1319-R1326 ◽  
Author(s):  
E. Dumonteil ◽  
H. Barre ◽  
J. L. Rouanet ◽  
M. Diarra ◽  
J. Bouvier
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Insulation ◽  
Cold Water ◽  
Threshold Temperature ◽  
Ambient Temperatures ◽  
Adaptation To Cold ◽  
Marine Life ◽  
Shell Temperature ◽  
Skin Temperatures

Penguins are able to maintain a high and constant body temperature despite a thermally constraining environment. Evidence for progressive adaptation to cold and marine life was sought by comparing body and peripheral skin temperatures, metabolic rate, and thermal insulation in juvenile and adult Gentoo penguins exposed to various ambient temperatures in air (from -30 to +30 degrees C) and water (3-35 degrees C). Juvenile penguins in air showed metabolic and insulative capacities comparable with those displayed by adults. Both had a lower critical temperature (LCT) close to 0 degree C. In both adults and juveniles, the intercept of the metabolic curve with the abscissa at zero metabolic rate was far below body temperature. This was accompanied by a decrease in thermal insulation below LCT, allowing the preservation of a threshold temperature in the shell. However, this shell temperature maintenance was progressively abandoned in immersed penguins as adaptation to marine life developed, probably because of its prohibitive energy cost in water. Thus adaptation to cold air and to cold water does not rely on the same kind of reactions. Both of these strategies fail to follow the classical sequence linking metabolic and insulative reactions in the cold.

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