SACCADIC INTRUSIONS
ANATOMICAL LESIONS:
NUCLEUS PREPOSITUS HYPOGLOSSI (NPH)
MEDIAN VESTIBULAR NUCLEUS (MVN)
INTERSTITIAL NUCLEUS OF CAJAL (INC)
STEP/ NEURAL INTEGRATOR LESIONS CAUSES
GAZE HOLDING PROBLEM
AFFECT VISION IF FREQUENT AND LARGE
MICROSACCADES
NORMAL/ OBLIQUE/ <0.5DEGREE
REQUIRED TO PREVENT VISUAL FATIGUE
CAN BE SEEN ONLY WITH OPHTHALMOSCOPE
​
SQUARE WAVE JERKS (SQWJ)
AMPLITUDE 0.5-5 DEGREE
MACRO >5 DEGREE
INCREASED IN SMOKERS
ABNORMAL SQWJ
FREQUENCY >16/MIN WITH FIXATION
FREQUENCY >20 IN DARK
MULTI-PLANAR/ DYSCONJUGATE
TYPES
UNIPHASIC
BIPHASIC (RIGHT AND THEN LEFT )
BECOMES MORE FREQUENT AND PROMINENT
PURSUIT MOVEMENT
LATERAL GAZE THEN CENTRE
FRIEDREICH'S ATAXIA/ PSP
ARNOLD CHIARY MALFORMATION
​
SQUARE WAVE OSCILLATIONS
CONTINUOUS SQWJ
​
MACROSACCADIC OSCILLATIONS
INTER SACCADIC INTERVAL PRESENT
CROSSES MIDLINE
CRESCENDO DECRESCENDO
ASSOCIATED WITH HYPER-METRIC SACCADE
PRODUCED BY GAZE SHIFT AND PURSUIT
FASTIGIAL NUCLEUS/ VERMIS LESION
SEEN IN FRIEDREICH'S ATAXIA
​
SACCADIC OSCILLATIONS
​
ANATOMICAL LESION:
OMNIPAUSE NEURONS LESION
​
FLUTTER
SACCADES WITHOUT INTER-SACCADIC INTERVAL
FLUTTER DYSMETRIA:
SACCADE TERMINATE IN BURST OF FLUTTER
DOUBLE SACCADIC BURST:
MINIMAL EXPRESSION OF FLUTTER
​
OPSOCLONUS [LINK]
LARGER THAN FLUTTER
CHOATIC/ OMNIDIRECTIONAL
​
.png){kind=small}
DISORDERS/ CONDITIONS
​
ABETALIPOPROTEINAEMIA
MEDIAL RECTUS PALSY
REDUCED CONVERGENCE
SACCADES: SLOW/ HYPOMETRIC
OKN: ABSENT FAST PHASE
​
AVED
OCULOMOTOR APRAXIA
INCREASED SACCADIC LATENCY
HEAD THRUST/BLINK FOR EYE MOVEMENT
NYSTAGMUS
STRABISMUS
​
NIEMAN PICK- TYPE C
VSGP: EARLY
HSGP: LATE
​
GAUCHER DISEASE
HSGP: EARLY
VSGP: LATE
HORIZONTAL GAZE ROUND THE HOUSE
OCULOMOTOR APRAXIA
​
ADCY5
VERTICAL SACCADE HYPOMETRIC
OCULOMOTOR APRAXIA
SACCADIC INTRUSIONS
​
MSA
SQUARE WAVE JERKS
HYPOMETRIC SACCADES
IMPAIRED VOR SUPPRESSION
SPONTANEOUS/ POSITIONAL DOWNBEAT NYSTAGMUS
PSP
MACRO SQUARE WAVE JERKS
INCREASE WITH FIXATION
REDUCE IN DARK.
​
ARNOLD CHIARI MALFORMATION
DOWN BEAT NYSTAGMUS
MACRO SQUARE WAVE JERKS
​
FRIEDREICH ATAXIA
MACRO SQUARE WAVE JERKS
MACROSACCADIC OSCILLATIONS
​
SCA24
SCA WITH SACCADIC INTRUSIONS
​
​
BRAIN STEM LESIONS LOCALIZATION
MEDIAL LONGITUDINAL FASCICULUS
INTERNAL NUCLEAR OPHTHALMOPLEGIA
SKEW/ OCULAR TILT REACTION
CONTRALATERAL EYE DOWN
CONTRALATERAL HEAD TILT (TRANSIENT)
UPBEAT + TORSIONAL NYSTAGMUS (TRANSIENT)
VERTICAL OSCILLOPSIA (TRANSIENT)
​
OMNIPAUSE NEURON INHIBITION OR
BURST NEURONS EXCITABILITY
FLUTTER
OPSOCLONUS
​
VI CN NUCLEUS
IPSILATERAL GAZE FAILURE
IPSILATERAL SACCADE FAILURE
IPSILATERAL PURSUIT FAILURE
​
PPRF
SACCADE VELOCITY REDUCED
IBN (INH BURST NEURONS)
INH OTHER SIDE 6TH
MVN (LSCC)
GAZE EVOKED NYSTAGMUS
SUPERIOR VESTIBULAR NUCLEUS
(ANTERIOR SEMICIRCULAR CANAL)
UPBEAT NYSTAGMUS
CAUDAL MEDULLA OR
CENTRAL TEGMENTAL TRACT LESIONS
UPBEAT NYSTAGMUS
​
LATERAL MEDULLARY SYNDROME
IPSILATERAL PULSION (UTRICLE CONNECTIONS)
SKEW OTR
IPSILATERAL EYE DOWN
IPSILATERAL HEAD TILT
GAZE EVOKED NYSTAGUS (MVN)
HYPERMETRIC SACCADE (ICP LESION)
​
CEREBELLUM LESION LOCALIZATION
FASTIGIAL NUCLEUS
MOST LESIONS BILATERAL
HYPERMETRIC SACCADE
MACROSACCADIC OSCILLATIONS
SQUARE WAVE JERKS
​
INFERIOR CEREBELLAR PEDUNCLE
SUPERIOR CEREBELLAR PEDUNCLE
FASTIGIAL
HYPERMETRIC SACCADE
​
CENTRAL TEGMENTAL TRACT (CTT)
DENTATE/ INFERIOR OLIVARY NUCLEUS
PENDULAR NYSTAGMUS
MYORHYTHMIA
OCULOPALATAL MYOC (1-2HZ)
OPSOCLONUS (DEN)
​
FLOCULUS LOBE
GAZE EVOKED NYSTAGMUS
DOWNBEAT
REBOUND NYSTAGMUS
(MVN LESION: NO REBOUND ONLY GAZE EVOKED NYSTAGMUS)
DOWN BEAT NYSTAGMUS
PURSUIT
​
SUPERIOR CEREBELLAR INFARCT
ANTERIOR VERMIS INHIBITS FASTIGIAL NUCLEUS
FASTIGIAL STIMULATES MVH
LESION OF ANTERIOR VERMIS:
GAZE EVOKED NYSTAGMUS (30%)
​
VERMIS
SACCADIC HYPOMETRIA
​
DORSAL VERMIS
HYPOMETRIA SACCADE IPSILATERAL
​
UVULA/ NODULUS
POSITIONAL UB/ DB NYSTAGMUS
PERIODIC ALTERNATE NYSTAGMUS
(NEUTRAL/ PRIMARY POSITION)
HEAD SHAKE VERTICAL NYSTAGMUS
POSITIONAL APOGEOTROPIC HORZONTAL NYSTAGMUS
​
​
​