1. Overview of NYSTAGMUS
Vivek Patel MD

2. OBJECTIVES
 Definition, description
 Neuroanatomical basis
 Instrinsic localizing value
 Representative cases

3. DEFINITION
 Disorder of ocular motor instability resulting in
spontaneous, involuntary, rhythmic oscillations
of the eyes
 Congenital vs. acquired
 “jerk” nystagmus vs. pendular
 “true” nystagmus vs. nystagmoid movements

4.  Conjugate vs. disconjugate vs. dissociated
 Trajectory may be horizontal, vertical, torsional,
or mixed
 Description of amplitude, frequency, velocity,
and intensity
 may vary with changes in gaze position
 May be influenced by the integrity of the
afferent visual system
 May exhibit a “null” point

5.  3 main mechanism of maintaining steady
gaze:
 1) fixation: a) prevent retinal image drift
b) suppress unwanted saccades
 2) VOR
 3) eccentric gaze holding

6.  Pulse (phasic) and step (tonic) outputs must be
balanced for appropriate gaze-holding.
 Significant cerebellar (vermis) calibration
 Horizontal: phasic = PPRF
tonic = NPH, MVN = neural integrators
Vertical: phasic = riMLF
tonic = iNC = neural integrator

7. NEUROANATOMICAL BASIS
Leigh & Zee, Neurology of Eye Movements, 3rd
ed., 1998Leigh & Zee, Neurology of Eye Movements, 3rd
ed., 1998

8. Not always a sign of disease…
 Physiological:
 Usually conjugate
 Preserves clear vision during self-rotation
 unsustained end-point nystagmus
 Vestibular nystagmus (brief sustained rot.)
 OKN (visually driven….uses pursuit mech.)

9. CHILDHOOD NYSTAGMUS
 Congenital nystagmus:
 usually recognized in first few months of life – life long
 May have good vision or poor vision
 Most often occurs in isolation (motor), but may be associated
with albinism, LCA, achromatopsia, or optic atrophy
 Uniplanar, horizontal trajectory irrespective of gaze position
 No oscillopsia
 Reversal of OKN direction
 Exponential increase in slow phase velocity
 Conjugate
 Null point (may have resultant head turn)
 Amplified by attempted fixation (distant)
 Dampened by convergence and darkness
 Absent in sleep
 Association with esotropia

10.  Latent nystagmus:
 Usually appears within first few months of life
 Horizontal jerk nystagmus appearing only
under monocular viewing conditions
 Fast phase beats away from occluded eye
 Strong association with esotropia
 Usually poor stereopsis
 May explain subnormal visual acuity tested
monocularly
 Manifest latent nystagmus:
 Present even when both eyes are open
 Loss of peripheral fusion

11.  Monocular nystagmus of childhood:
 Usually monocular, vertical, low amplitude oscillation
 Eye with nystagmus may have afferent visual dysfunction
 Requires neuroimaging (chiasmal glioma)
 Spasmus Nutans:
 Asymmetric or monocular low-amplitude oscillations
 May be horizontal, vertical or torsional
 Head nodding
 Torticollis or abnormal head posture
 Begins in infancy, usually resolved by age 3 to 5
 Requires neuroimaging

12. ACQUIRED NYSTAGMUS

13. PERIPHERAL VS. CENTRAL
VESTIBULAR NYSTAGMUS
PERIPHERAL
 Severe vertigo
 Days to weeks duration
 Hearing loss, tinnitus
associated
 Usually horizontal with
torsion
 Very rarely purely vertical or
torsional
 Dampened with visual
fixation
 Commonly peripheral
vestibular organ dysfunction:
labyrynthitis, meniere’s
CENTRAL
• None or mild vertigo
• Often chronic
• May be purely vertical or
torsional
• visual fixation usually has no
effect
• Etiologies commonly
vascular, demyelination,
pharmacologic, toxic
• Downbeat, upbeat, torsional

14.  Gaze evoked nystagmus:
 One of the most common forms of central
nystagmus
 Inability to maintain eccentric gaze
 “leaky integrator” -- miscalibration between pulse
and step inputs
 Symmetric
 cerebellar flocculus implicated
 Age, anti-convulsant therapy, alcoholic
degeneration, stroke, demyelination
 Baclofen effective

15.  Downbeat nystagmus:
 Defect in vertical gaze holding
 Asymmetric inputs from vertical semi-circular
canals produce upward slow drift of eyes
 Defect in fastigial nuclei calibration
 Secondary downward corrective fast phase
 Obeys Alexander’s law
 Localizes to cervico-medullary junction
 Arnold-Chiari malformation
 Treatment with baclofen, clonazepam, base-out
prisms

16.  Upbeat nystagmus:
 Present in primary position or upgaze
 Classically localizes to a lesion of anterior cerebellar
vermis
 More generally implicates posterior fossa disease
 Etiologies include stroke, cerebellar degeneration,
demyelination, toxic exposures
 Periodic alternating nystagmus:
 Horizontal oscillation characterized by a periodic reversal
in the direction of nystagmus due a shift in the null point
 Duration of cycles from 30 seconds to 6 minutes
 Classically a lesion of the cerebellar nodulus
 MS, drugs, ethanol, paraneoplastic syndromes
 Baclofen effective

17. •Bruns nystagmus:
• associated with CPA tumors
• high frequency, low amplitude
nystagmus (fast-phase away from lesion)
• low frequency, large amplitude
nystagmus on ipsilateral gaze (fast phase
toward lesion)
• shift from eye movement response to
vestibular imbalance to that of defective
gaze holding

18.  See-saw nystagmus:
 Disconjugate vertical nystagmus (pendular vs. jerk)
 Upward moving eye intorts while downard eye extorts
 Localizes to lesions of diencephalon
 Visual fields may be useful (disruption of afferents to cerebellum)
 Ocular flutter/opsoclonus:
 Burst-like, incoordinated saccadic excursions with high frequency,
low amplitude
 No intersaccadic latency
 Purely horizontal: ocular flutter
 Multiplanar: opsoclonus
 Reflect pause cell dysfunction (pons)
 Must consider paraneoplastic etiology: SCC of lung, ovarian,
breast CA
 Neuroblastoma in children

20. Acquired pendular nystagmus:
 Can be vertical, horizontal, torsional, or any
combination (usually one predominates)
 Usually disconjugate or dissociated
 Oscillopsia ++
 MS, whipple’s, oculopalatal myoclonus
 Combination of afferent dysfunction and
cerebellar calibration

21.  Oculopalatal myoclonus:
 Vertical pendular eye movements associated with rhythmic
upward movement of palate
 Caudal brainstem pathology: red nucleus, inferior olive, and
dentate nuc.
 Convergence-retraction nystagmus:
 Commonly associated with dorsal midbrain syndrome
 May be associated with other Parinaud’s findings
 Not a true nystagmus: co-contraction of horizontal recti on
attempted upgaze
 Localizes to pretectal area, posterior commissure, INC
 Pineal cyst or tumor, demyelination, stroke

22. SUMMARY
 Recognize physiologic vs. pathological
 Appropriate characterization important
 Presence of nystagmus may correlate with significant
afferent visual dysfunction
 Recognition of nystagmus may facilitate subsequent
neurological or medical investigations (know where to
look)
 Treatment options do exist