Difference between ENG & VNG ?

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Difference between ENG VNG?
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What is ENG ?

• Electronystagmography (ENG)  is an important test
  done to evaluate patients with vertigo, dizziness
  and balance problems. The study of eye movements
  provides a lot of information about the
  functioning of the brain and the balance system.
  ENG is used to second eye movements in different
  conditions and with different tests. By analyzing
  these movements, we are able to understand the
  area affected by the disorder.
• ENG detects eye movements by virtue of a change
  in the cornea retinal potential during these
  movements. The changes in potential are picked up
  by surface electrodes placed near the eyes of the
  patient. Findings of ENG must be correlated with
  the history given by the patient and other neuro
  ontological tests to identify the cause of
  vertigo or dizziness.

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What is VNG ?

• Videonystagmography (VNG) is the most
  non-invasive, accurate, reliable and affordable
  way of evaluating the vestibular and oculomotor
  systems. This technology is used for observation,
  measurement and analysis of eye movement during
  various oculomotor and vestibular tests. This
  equipment eradicates the issue of myogenic and
  electrical noise seen in ENG.
• It evaluates peripheral and central vestibular
  functions
• VNG has a user friendly binocular goggle design

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Difference between ENG VNG?

• ENG

• VNG

• Uses electrodes to record corneo retinal
  potential.
• The detailed finding of oculomotor tests not
  possible.

• Direct recording of eye movements with infrared
  cameras.
• Each oculomotor test like gaze, saccades, smooth
  pursuit, skew deviation and optokinetic
  stimulation can be studied in detail. 

Continued
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Difference between ENG VNG?

• ENG

• VNG

• Reviewing and replaying tests not possible.
• Able to record horizontal eye movements. Vertical
  eye movement recording is not very accurate.
  Cannot record torsion.

• Able to replay tests, visualize in slow motion
  and review videos.
• Able to record eye movements in horizontal and
  vertical planes with high precision and
  graphically present the nystagmus with slow-wave
  velocity and a number of beats. Torsional eye
  movements are well presented on video.

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Tests Conducted During ENG and VNG Examination

• Test for spontaneous nystagmus  Nystagmus is the
  jerky oscillatory movement of the eyes caused by
  disturbances in the balance system. In many
  cases, this nystagmus cannot be accurately
  diagnosed by naked eye examination. VNG
  examination allows high resolution magnified
  imaging of eye movements.
• Test for gaze  This test checks the ability to
  hold gaze at a point. Patients with balance
  disorders may have problems in holding their eyes
  steady on a fixed point.
• Saccades  This test checks the ability to move
  the eyes and appropriately focus on another
  object of interest
• Smooth pursuit  A light moving like a pendulum
  is presented to be followed by the patient with
  eye movements without moving the head. The
  ability to track it with the required velocity
  and precision is measured.
• Other tests done  include skew deviation,
  hyperventilation, vibration, valsalve and
  optokinetic stimulation.

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