Nystagmus

Clinical Exam

Physiological nystagmus is assessed by moving the patient’s head from left to right in a horizontal plane, and then back again.  As the head is moved movements of the eyes should be assessed.  Normal physiological nystagmus results in rapid movement of the eyes towards the direction of the movement and a slower movement of the eyes opposite the direction of the movement.
           Spontaneous nystagmus can be seen by evaluating a patient in a normal resting position.  Spontaneous nystagmus is an abnormal finding.  Pathological nystagmus may also be appreciated when the patient’s head is placed in new positions, for example with the neck extended with the head held straight up or the head extended laterally to either side.  The eyes should be stationary when the head is not moving but in pathological conditions a nystagmus may be appreciated with these novel positions of the head.  The authors prefer to assess for this so called positional or induced nystagmus when the patient is on his/her back with the head extended.

Anatomic Pathway

Physiological nystagmus is assessed by moving the patient’s head from left to right in a horizontal plane, and then back again.  The head movement stimulates the vestibular nerve (CN VIII) via a synaptic relationship with the bony and membranous labyrinth as well as the receptor organ.  The efferent response is mediated by the oculomotor (CN III), trochlear (CN IV), and abducent (CN VI) nerves.

Overview of Anatomy

Physiological nystagmus is assessed by moving the patient’s head from left to right in a horizontal plane, and then back again.  The head movement stimulates the vestibular nerve (CN VIII) via a synaptic relationship with the bony and membranous labyrinth as well as the receptor organ.  The efferent response is mediated by the oculomotor (CN III), trochlear (CN IV), and abducent (CN VI) nerves. For more in-depth neuroanatomy read the E-book on the vestibular system.

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Anatomic Sections

Physiological nystagmus is assessed by moving the patient’s head from left to right in a horizontal plane, and then back again.  The head movement stimulates the vestibular nerve (CN VIII) via a synaptic relationship with the bony and membranous labyrinth as well as the receptor organ.  The efferent response is mediated by the oculomotor (CN III), trochlear (CN IV) and abducent (CN VI) nerves.