scope:

General

This Standard specifies procedures for conducting six separate tests, which, together with the data analysis and reporting requirements specified in this Standard, constitute the Basic Vestibular Function Test Battery. The six tests cover:

(a) spontaneous nystagmus (see 5.2);

(b) gaze-evoked nystagmus (see 5.3);

(c) saccade test (see 6);

(d) pursuit testing (see 7);

(e) positioning and positional nystagmus (see 8); and

(f) caloric testing (see 9).

Each of these tests evaluates a response of the vestibular system by the vestibulo-ocular reflex through the measurement of electrical signals generated by eye movements recorded by electrooculography.

Subjects

This Standard may be used to evaluate basic vestibular function in any human subject without restriction on age or sex.

NOTE Children under the age of about 4 may not be able to participate in all tests for various reasons, e.g., inability to follow verbal instructions.

Test subjects, however, must have functional retinas in both eyes and be able to see light through each eye separately to determine conjugacy of eye movements (i.e., ability to move both eyes synchronously or together).

Applicability of this Standard to some subjects may be limited by two variables. The test utilizing caloric stimulation depends upon heat transfer to the vestibular end organ, and is highly variable among individuals. The electro-oculogram, one method of measuring eye movement used in this Standard, depends on the existence of a corneoretinal potential which may be absent in certain cases of visual pathology. The use of video methods to measure eye movements requires that the eye can be visualized by video cameras well enough so that image processing methodology (e.g., tracking the iris-pupil limbus) can be effectively applied.

Purpose

The purpose of this Standard is to define a basic battery of tests to evaluate the vestibular function in humans. These tests define a minimum set of procedures for the purpose of establishing a common basis for comparison of data on subjects with both normal and dysfunctional vestibular function. These tests are not necessarily intended to replace more extensive tests used for detailed clinical or research purposes in specific applications but are intended to form a minimal base to be included in such studies.

Applications

Evaluation of vestibular function may be used in assessing disease, aging, and ability to function in certain occupations. Susceptibility to falling down, vertigo, motion sickness, and the ability to adapt to a weightless environment are related in greater or lesser degree to vestibular function.

This Standard does not include interpretation of the tests of vestibular function. For informational purposes, examples of test interpretations for subjects with normal and abnormal test results are provided in Annex A.