videonistagmografia

Videonistagmografía, also known as VNG, is a diagnostic procedure that records and analyzes eye movements to detect nystagmus and assess the vestibulo-ocular reflex. The test uses infrared cameras integrated into goggles to capture digital eye movement data, providing a quantitative evaluation of ocular motility.

The examination includes several components. Spontaneous nystagmus, gaze-evoked nystagmus, and nystagmus induced by positional changes are recorded. Caloric testing is a key part of VNG and involves stimulating each ear with warm and cold air or water to provoke responses from the horizontal semicircular canals. Additional assessments may include positional maneuvers such as the Dix-Hallpike test to diagnose benign paroxysmal positional vertigo (BPPV), as well as evaluation of smooth pursuit and optokinetic responses, and saccades. Calibration and proper head stability are essential for accurate measurements.

Interpretation focuses on the presence, direction, and characteristics of nystagmus, as well as asymmetries in caloric responses. Peripheral vestibular disorders typically produce unidirectional, fatigable nystagmus with corresponding caloric asymmetry, whereas central vestibular disorders may show vertical or direction-changing nystagmus and relatively preserved caloric responses. VNG helps differentiate peripheral from central causes of vertigo and can aid in diagnosing conditions such as BPPV, vestibular neuritis, Ménière’s disease, and central vestibular pathway disorders.

Advantages of VNG include noninvasiveness, patient comfort, and the ability to quantify eye movements. Limitations include reliance on patient cooperation, potential calibration errors, and the caloric test’s restriction to low-frequency vestibulo-ocular responses, which may not reflect high-frequency function.