Search results
Results from the WOW.Com Content Network
Videonystagmography (VNG) is a type of testing used to assess vestibular and central nervous system function through the use of eye movement tracking, specifically evaluating nystagmus. [1] The older version of technology used to perform these tests, known as electronystagmography (ENG), leverages electrophysiological signals.
A newer standard for the recording is the use of infrared video systems which allow for a more detailed observation and analysis of these eye movements, called video nystagmography (VNG). [3] A similar test is performed for testing vertigo by using the caloric reflex test, which can be induced by air or water of specific temperatures, typically ...
The stimulus needs to be a transient, rapidly changing pulse (i.e. linear jerk stimulus). A rectangular jerk step/pulse is generated by an electromechanical shaker. The main downfall of the VsEPL response is the presence of electrical artifacts due to movement and touching of the wires/electrodes during testing.
The test is commonly used by physicians, audiologists and other trained professionals to validate a diagnosis of asymmetric function in the peripheral vestibular system. Calorics are usually a subtest of the electronystagmography (ENG) battery of tests. It is one of several tests which can be used to test for brain stem death.
When performing the Dix–Hallpike test, patients are lowered quickly to a supine position (lying horizontally with the face and torso facing up) with the neck extended 30 degrees below horizontal by the clinician performing the maneuver. [3] The Dix–Hallpike and the side-lying testing position have yielded similar results.
OKR is typically evoked by presenting full field visual motion to a subject. The optokinetic drum is a common clinic tool used for this purpose. The drum most commonly contains sinusoidal or square-wave stripes that move across the subject's field of view to elicit strong optokinetic eye movements.
Romberg's test is not a test of cerebellar function, as it is commonly misconstrued. Patients with severe cerebellar ataxia will generally be unable to balance even with their eyes open; [ 6 ] therefore, the test cannot proceed beyond the first step and no patient with cerebellar ataxia can correctly be described as Romberg's positive.
The Jaeger chart is an eye chart used in testing near visual acuity.It is a card on which paragraphs of text are printed, with the text sizes increasing from 0.37 mm to 2.5 mm. [1] This card is to be held by a patient at a fixed distance from the eye dependent on the J size being read.