How do you assess Optokinetic nystagmus?
Assessment of Optokinetic Nystagmus OKN eye movements involve two phases: the first is smooth pursuit eye movements in the direction of the moving target and the second is nystagmus in the contralateral direction. 1. To test OKN, use a device such as cloth tape, drum, or mobile phone application.
What does spontaneous nystagmus indicate?
Spontaneous nystagmus denotes movement of the eyes without a cognitive, visual or vestibular stimulus. Most commonly spontaneous nystagmus is caused by a vestibular imbalance. Normally, both vestibular nerves fire at a tonic rate.
What does horizontal nystagmus indicate?
Nystagmus is a condition where the eyes move rapidly and uncontrollably. They can move: side to side (horizontal nystagmus) up and down (vertical nystagmus)
What is Optokinetic movement?
The optokinetic response (OKR) is a reflexive eye movement induced by motion of a wide visual field (Collewijn, 1991). When observers are exposed to sustained visual motion, an alternating pattern of slow and fast eye movements emerges (slow and quick phases), called optokinetic nystagmus (OKN).
What is a positional nystagmus test?
What is positional testing? Positional testing is used to determine whether a change of position of the patient’s vestibular systems in space provokes nystagmus. Both central and peripheral vestibular lesions can cause positional nystagmus and vertigo, and the examination focuses on distinguishing the two.
What is central positional nystagmus?
Central positional nystagmus (CPN) can be classified into the paroxysmal (transient) and persistent forms. The paroxysmal CPN has the features suggesting a semicircular canal origin regarding the latency, duration, and direction of nystagmus.
What is peripheral nystagmus?
Patients with a peripheral disorder demonstrate nystagmus to the contralateral side which suppresses with visual fixation. Nystagmus improves with gaze towards the lesion and worsens with gaze opposite the lesion. Patients may also report a falling sensation.
What is rotational nystagmus?
Torsional (rotary) nystagmus refers to a rotary movement of the globe about its anteroposterior axis. Torsional nystagmus is accentuated on lateral gaze. Most nystagmus resulting from dysfunction of the vestibular system has a torsional component superimposed on a horizontal or vertical nystagmus.
What does the word Optokinetic mean?
Definition of optokinetic : of, relating to, or involving movements of the eyes.