Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 6440085

Caloric tests.

C W Hart
View original source ↗Export metadata ↓

Abstract

The caloric test is still the most useful vestibular test by far. Rotatory tests may allow more accurate control of the stimulus and the response parameters may vary less in normal individuals, but only the caloric test allows individual testing of each ear. By various means described in this article, it is possible to minimize potential sources of error and thus maximize the reliability of the test. Although the test allows a good measure of horizontal semicircular canal function and, by inference, an estimate of labyrinthine disease, the fact that the reflex arc traverses the vestibular nerve and brain stem renders this pathway liable to damage by central vestibular disease. Thus the electronystagmographic recording of the caloric nystagmus response may show a variety of changes, depending on the site and nature of the central vestibular lesion. Some of these changes are discussed.

Explore related subjects

Caloric TestsElectronystagmographyHumansLabyrinth DiseasesPostureVestibular Function TestsJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C W Hart. 1984. Caloric tests.. https://doi.org/10.1177/019459988409200613

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

A visual suppression test using post-rotatory nystagmus.

The visual suppression test is one method for examining the function of visual fixation and visual influence on vestibular nystagmus. In this study the visual suppression test using post-rotatory nystagmus was investigated in 65 normal subjects and 142 clinical cases with cerebellar lesions. In 65 normal subjects the mean +/- standard deviation of visual suppression of the slow phase velocity on post-rotatory nystagmus was 69 +/- 11%. As to the stimulation for visual suppression test, the post-rotatory method using rotatory stimulation is milder than caloric stimulation. This method is far simpler to analyze than the visual suppression test using pendular rotatory nystagmus and other vestibulo-ocular reflex tests. In the 142 patients with cerebellar lesions, reduced or abolished visual suppression on post-rotatory nystagmus was seen in 89 patients with radiologically confirmed disturbances in the vestibulo-cerebellum. And this method could identify the lesion side in the cerebellum. These results showed a correlation between the visual suppression test using post-rotatory nystagmus and one using caloric nystagmus in 65 normal subjects and 142 clinical cases with cerebellar lesions.

Caloric Tests↗
PubMed1992

Measurement, analysis, and modelling of the caloric response. 1. A descriptive mathematical model of the caloric response over time.

A mathematical model for describing the caloric response over time offers many important advantages over the commercially-available qualitatively-fitted curves that are now used by the clinician for evaluating caloric results. In this report advances in the development of a nonlinear least-squares mathematical model are discussed and the roles and derivations of fitting parameters and curve-derived indices are outlined. This model provides a rigorous and objective description of the caloric response in its entirety with four continuous parameters. These fitting parameters make it possible to 1) describe individual caloric responses precisely and uniquely, 2) compare pairs of individual caloric responses or groups of caloric responses statistically, 3) extract information not previously available, 4) quantify variability within the caloric response, and 5) model physical properties of the caloric stimulus and physiological variables affecting the caloric response. Results from this model are compared with the results from our earlier models and with traditional multiparameter caloric results.

Caloric Tests↗
PubMed1992

An evaluation of commercial water irrigation systems used for caloric testing.

The post-1982 Grant Caloric Test Apparatus, and the Atmos Variotherm were evaluated and compared to BS5724 Part 1 (1989). Quality of construction is satisfactory, but design features may result in failure of tests for which this type of equipment should conform; namely splash, liquid leakage and spillage. For the Variotherm the proximity of the water piping to the electrical parts could result in wetting of the electrical units in the event of a leakage. The large vents in the Grant tanks allow easy access of water to electrical parts in the event of splashing. Both sets of equipment fail BS5724 Part 1 (1989) with respect to labelling. The Grant irrigation nozzle is well designed, but the Variotherm nozzles are not so, as they can accidentally pass down the external auditory meatus causing meatal wall or tympanic membrane damage. Both sets of equipment passed on electrical safety test for Class I Type B equipment. Cut-outs are fitted to prevent heating in the absence of water or over-heating of the water. The 44 degrees C Grant tank cut out after 20 s in the absence of water and at 49 degrees C as the water temperature rose above the operating temperature. The Variotherm heater did not operate in the absence of a water supply. The Variotherm thermal cut-out was not assessed. The force of the water at recommended flow rates using the Variotherm 'standard' metal nozzle was considered to pose a potential hazard of tympanic membrane perforation, and has subsequently been withdrawn by the supplier. The plastic nozzle minimized any such risk. The Variotherm is easier to use due to the well-designed trigger handle for controlling water delivery. Both sets of equipment performed at the correct temperature to within +/- 0.5 degrees C and achieved a flow rate of 250 ml in 30 s.

Caloric Tests↗