Videonystagmography

The goals of any test that evaluates balance function are manifold; primarily to determine the presence of a true balance disorder and to topographically locate it. Secondarily, to determine the extent of residual functional abilities of the patient as regards the ‘deficit’ caused by the disorder, and evaluate the possibility of recovery. Thirdly, and most importantly, to determine whether the individual is likely to benefit from some therapeutic modality, whether single or combined, based on the results of the tests. Testing for vertiginous patients involves eliciting a detailed history, followed by a clinical evaluation. Investigations include the audiological, radiological and computerized tests. Computerized vestibular testing includes various computerized modules, such as: Electronystagmography (ENG), videonystagmography (VNG), rotational testing, computerized dynamic posturography (sensory organizational test—SOT; motor control testing—MCT) and vestibular evoked myogenic potential (VEMP) testing. VNG is thus only one of the computerized tests and should always be interpreted in conjunction with the others mentioned above. This, however, does not mean that VNG should be performed in all patients complaining of vertigo. It is thus, prudent to understand the indications and possible information that may be obtained from a VNG evaluation and its application to clinical science. Analysis is often carried out by a technician and the results presented to the surgeon or physician. The analysis is often carried out automatically, or at least semi-automatically by a computer, where the automatic artefact rejection is usually poor, or in the least, suboptimal. These potentially ‘weak links’ in the chain can often mislead the clinician, and lead to errant diagnosis, such as ‘central vestibular disorder’, either due to an artifactual recording, or poor interpretation! It is thus, extremely important, that the ENG/VNG results are correlated with the clinical evaluation of the same tests, which may be done with the naked eye or in the least, using Frenzel's glasses. How to cite this article Hathiram BT, Khattar VS. Videonystagmography. Int J Otorhinolaryngol Clin 2012;4(1): 17-24.