Video Nystamography (VNG)
VNG identifies abnormalities within the VESTIBULAR and OCULOMOTOR systems. All living organisms monitor their environment, and one critical aspect of that environment is gravity and the orientation of the body with respect to gravity. The vestibular system performs essential tasks. It engages a number of reflex pathways that are responsible for making compensatory movements and adjustments in body position. It also engages pathways that project to the cortex to provide perceptions of gravity and movement.
The eyes and the Oculomotor system are the only sensory system that gives input to every area of the brain. Some of those areas are involved in regulating posture, movement, balance, and sensory input. It is composed of pathways connecting various parts of the brain dealing with controlling emotions, heart rate, breathing, sleeping, vision, personality, higher thinking, and much more.
When we look up or down, right or left, fast or slow, each of those movements and directions are controlled by varying parts of the brain. The VNG test measures the brain by tracking these eye movements such as gaze holds, pursuits, saccades, nystagmus, and optokinetic reflexes. The test data collected helps objectively document abnormal eye movements. These abnormalities in eye function are due to lesions/breakdowns in specific areas of the brain. By identifying these breakdowns in eye movement we’re also identifying the dysfunctional part of the brain. By so doing we identify the cause of the symptoms a person is facing and how to fix the dysfunctional area.
How the test is performed: VisualEyes™ goggles are placed on person and goggles are aligned. Eye makeup must not be worn or must be removed before test is performed. The test is performed while in the dark. While holding head in place and using only the eyes, the person tracks a target on a screen as the target moves in various directions and speeds. Upon completion of test, the lights are turned on and goggles are removed.
(CAPS® - Comprehensive Assessment of Postural Systems)
Posturography is a general term that covers all techniques used to measure postural control in an upright stance, in either static or dynamic conditions. Among those techniques is Computerized Dynamic Posturography (CDP), also called test of balance (TOB). CDP is a non‐invasive specialized clinical assessment technique used to quantify the central nervous system adaptive mechanisms (sensory, motor, and central) involved in the control of posture and balance, both in normal (such as in physical education and sports training) and abnormal
conditions. CDP tests the subjects balance control and postural stability, identifying impairments of the visual, somatosensory, proprioception and vestibular systems and further pinpointing functional or cognitive brain impairments. These impairments may cause pain in the body, anxiety, dizziness, vertigo, inattention etc. By finding these impairments we can then correct the problem helping alleviate the symptoms.
How the test is performed: Patient removes shoes before beginning test. The patient wears noise cancelling headphones and steps onto the platform. While on the platform the patient will perform a series of tests with eyes open and closed. Patient steps off platform and a perturbation cushion (unstable surface) is placed on the platform. Patient will stand on the platform and perform another series of test with eyes opened and closed and head tilted in various positions. Upon completion of test the patient steps off the platform and removes headphones.
The Saccadometer was developed in close collaboration between a team at the Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, led by Dr Jan Ober, and Prof. Roger Carpenter from UK. It brings together understanding of the neural systems controlling eye movements, eye movement measurement technology, as well as advances in microelectronics and signal processing technology.
Saccades or Saccadic movements are Rapid eye movements such as looking from one word to the next and then back to the beginning when we read. The Saccadometer allows us to perform strict quantitative evaluations of saccadic/rapid eye movements. Saccadic movements are controlled by neural structures comprised of nearly every level of the brain. Many neurological and physiological disorders have a variety of effects on saccadic eye movement. The importance of measuring saccadic movements is that the movements or breakdowns of the movements are characteristic of the disease or dysfunction. By these measurements we can diagnose functionality and connectivity between of the neural structures and hemispheres in the brain to help determine best treatment to improve the dysfunctional area of the brain.
How the test is performed: The Saccadometer band will be placed around the patient's head and the Saccadometer rests on the nose and forehead. A laser light shines on a surface (wall) in front of the patient and the patient watches the target as it moves from position A to position B in a horizontal plane. The Saccadometer sensors measure the eye position, latency, and velocity as the eye moves. Upon completion of test the Saccadometer is removed.