The following general observations on the clinical yield of vestibular tests may be made, based on findings from a database of 10,000 patients who underwent the 3 types of vestibular testing (ie, ENG, SHA, and CDP) between 1985 and 1995 under the direct supervision of one of the coauthors (Hamid):
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First, the raw data tracings should be viewed and evaluated, particularly those acquired by using computerized systems, and clinicians should not rely on computerized analysis generated by the system software, even if the raw data are merely noise
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Second, overinterpretation of oculomotor findings is common, leading to unnecessary neurologic investigations, especially MRI; in the database, the yield for abnormalities of central eye movements, saccadic dysmetria, saccadic pursuit, asymmetric optokinetic response, and gaze-evoked nystagmus was less than 5%; therefore, ENG readers are advised to cautiously interpret eye movements
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Third, an ENG system prints outs only horizontal and vertical eye movements and is therefore insensitive to the pure torsional eye movements often seen with BPPV; video-based ENG (VNG) has the advantage of depicting and digitally recording pure torsional nystagmus for storing and reediting of the captured video signals
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Fourth, findings on chair and dynamic posturography are infrequently abnormal, and their routine use is probably not cost-effective
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Finally, most abnormalities detected by vestibular testing can be identified by means of a carefully conducted office vestibular examination
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Example of Frenzel goggles used for evaluation in neuro-otology clinic.
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Typical example of computer and headgear equipment used in neuro-otology clinic.
