Biomaterial Database

[Model of the formation of nystagmic reactions to a set of caloric tests]. 1981

M M Levashov, and Ia A Bedrov

The model can furnish additional information about the vestibulary system, when evaluating caloric tests. The model has been built with certain assumptions being made. The nystagmus intensity (the slow component rate during maximum intensity) is assumed to be proportional to the difference between energy levels (EL) of the right and left vestibular nuclear complexes (NC). El of each NC is equal to the afferent flow (AF) plus its inherent activity (IA). During caloric (two warm and two cold) tests IA remains constant. AF at rest is equal to spontaneous activity of receptors and during stimulation it increases or decreases in a linear fashion. Parameters of the model are: difference between intensities of reactions to warm and cold tests, difference between EL of two (right and left) unstimulated NC, and ratio of nystagmus intensity to the stimulus for each labyrinth. The behavior of the model during vestibular dysfunctions of various origin (changes in one of AF characteristics or changes in IA of one NC) is discussed. The diagnostic application of the model is illustrated by the discussion of nystagmometric data. The conclusion about vestibular dysfunction and its etiology can be made on the basis of statistic analysis of parameters of the model in the norm.

UI	MeSH Term	Description	Entries
D007759	Labyrinth Diseases	Pathological processes of the inner ear (LABYRINTH) which contains the essential apparatus of hearing (COCHLEA) and balance (SEMICIRCULAR CANALS).	Inner Ear Disease,Ear Disease, Inner,Ear Diseases, Inner,Inner Ear Diseases,Labyrinth Disease
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D002150	Caloric Tests	Elicitation of a rotatory nystagmus by stimulating the semicircular canals with water or air which is above or below body temperature. In warm caloric stimulation a rotatory nystagmus is developed toward the side of the stimulated ear; in cold, away from the stimulated side. Absence of nystagmus indicates the labyrinth is not functioning.	Barany Test,Barany's Test,Baranys Test,Caloric Test,Test, Barany,Test, Barany's,Test, Caloric,Tests, Caloric
D005133	Eye Movements	Voluntary or reflex-controlled movements of the eye.	Eye Movement,Movement, Eye,Movements, Eye
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014722	Vestibule, Labyrinth	An oval, bony chamber of the inner ear, part of the bony labyrinth. It is continuous with bony COCHLEA anteriorly, and SEMICIRCULAR CANALS posteriorly. The vestibule contains two communicating sacs (utricle and saccule) of the balancing apparatus. The oval window on its lateral wall is occupied by the base of the STAPES of the MIDDLE EAR.	Vestibular Apparatus,Ear Vestibule,Vestibular Labyrinth,Vestibule of Ear,Vestibulum Auris,Apparatus, Vestibular,Ear Vestibules,Labyrinth Vestibule,Labyrinth Vestibules,Labyrinth, Vestibular,Labyrinths, Vestibular,Vestibular Labyrinths,Vestibule, Ear,Vestibules, Ear,Vestibules, Labyrinth