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Neuro 3 Final > Nystagmus > Flashcards

Nystagmus Flashcards

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1
Q

Nystagmus is an ___, ___ movement of the eyes

A

involuntary

rhythmic

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2
Q

Nystagmus is often due to:

A

a disturbance in the vestibular system or its central processing pathways

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3
Q

Classification by Duration:

A

Continuous
Paroxysmal

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4
Q

Continuous nystagmus =

A

Ongoing eye movement at rest, not dependent on position or provocation

Seen in vestibular neuritis, central lesions

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5
Q

Paroxysmal nystagmus =

A

Sudden bursts of nystagmus, typically positional and brief (<60 sec)

Classic in BPPV

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6
Q

Classification by Direction:

A

Horizontal
Vertical
Torsional (rotary)
Mixed

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7
Q

Horizontal nystagmus =

A

Eye moves side to side

cause - BPPV, neuritis

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8
Q

Vertical nystagmus =

A

Up and down eye movement

cause - Central lesions (brainstem, MS)

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9
Q

Torsional (Rotary) =

A

Eye appears to spin or twist

cause - Posterior canal BPPV

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10
Q

Mixed nystagmus =

A

Combination of above

cause - Meniere’s, some central disorders

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11
Q

The ___ phase is the pathological part, nystagmus is always named for the direction of the ___ phase

A

slow

fast

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12
Q

(e.g., right-beating nystagmus = quick movement to the ___).

A

right

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13
Q

Physiologic Nystagmus =

A

Normal response to rotation, optokinetic stimulation

Example: spinning in a chair, looking out of a moving train

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14
Q

Pathologic Nystagmus =

A

Occurs spontaneously or abnormally

Seen in vestibular disorders

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15
Q

Types of Pathologic Nystagmus:

A

Spontaneous Nystagmus

Gaze-Evoked Nystagmus (GEN)

Positional Nystagmus

Congenital Nystagmus

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16
Q

Spontaneous Nystagmus =

A

Occurs without visual, cognitive, or vestibular stimulus

Indicates vestibular imbalance

Common in acute unilateral vestibular loss

Often horizontal jerk type

Follows Alexander’s Law in peripheral cases

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17
Q

Gaze-Evoked Nystagmus (GEN) =

A

Only present when gazing in a certain direction

Can be:
Pathologic (due to cerebellar/brainstem lesion)

OR a normal variant at end-range (“end-point nystagmus”)

Direction of nystagmus changes with gaze

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18
Q

Positional Nystagmus =

A

Triggered by changes in head position (e.g., Dix-Hallpike)

Seen in BPPV

Often torsional + up-beating (posterior canal BPPV)

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19
Q

Congenital Nystagmus =

A

Present from birth

Usually horizontal, pendular, and does not cause vertigo

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20
Q

Key Red Flags (Central Clues)

A

Direction-changing with gaze = central

Vertical nystagmus = central

No suppression with fixation = central

Poor smooth pursuit or associated neuro signs (diplopia, dysarthria, limb ataxia) = central

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21
Q

Nystagmus Can Be Triggered By:

A

position

gaze

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22
Q

Position-Triggered Nystagmus (Positional Nystagmus) =

A

nystagmus only occurs (or worsens) when the head is in certain positions

Common in:
BPPV (Benign Paroxysmal Positional Vertigo)

Brief, latency (1–5 sec), fatigues with repetition

Caused by otoconia moving in SCC → cupula deflection

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23
Q

BPPV (Benign Paroxysmal Positional Vertigo) =

A

Most common cause of positional nystagmus

Triggered by head movements (e.g., rolling over, looking up)

Seen with Dix-Hallpike test or Roll test

Often torsional and up-beating (posterior canal BPPV)

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24
Q

Gaze-Evoked Nystagmus (GEN) =

A

occurs when the eyes are held in an eccentric (not center) gaze — like looking far left or right

Common in:
Central vestibular disorders
Cerebellar lesions
Brainstem stroke
MS

Direction changes depending on gaze direction (e.g., right-beating when looking right, left-beating when looking left)

May be pathologic or a normal variant (“end-point nystagmus”)

Doesn’t usually come with vertigo

Persistent, not fatigable, may worsen with fixation removed

Due to impaired ability to hold eccentric gaze → neural integrator failure (central sign)

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25
position trigger =
type = Torsional or horizontal (brief, fatigable) source = Peripheral (e.g., BPPV) key signs = Triggered by Dix-Hallpike, latency, short duration
26
gaze trigger =
type = Horizontal or vertical (persistent, direction-changing) source = Central (e.g., cerebellum) key signs = Present only in eccentric gaze, no latency, no fatigue
27
Distinct from abnormal eye movements:
saccades smooth pursuits nystagmus oscillopsia
28
Saccades =
Quick, purposeful eye movements to shift focus Voluntary (or reflexive) Normal in tracking, but abnormal saccades (e.g., dysmetria) = central issue
29
Smooth Pursuits =
Tracking a moving object smoothly Voluntary Poor pursuits = cerebellar or central lesion
30
Nystagmus =
Involuntary, rhythmic back-and-forth movement Involuntary Always a sign of vestibular or neurologic issue (peripheral or central)
31
Oscillopsia =
Perception that environment is moving when it’s not Symptom, not an eye movement Common in bilateral vestibular loss
32
📌 Nystagmus is NOT a ____ — even though it has a fast phase, it's ___ and usually pathologic when ___
saccade involuntary spontaneous or persistent
33
Congenital Nystagmus:
Present at birth or early infancy Often horizontal, pendular, and doesn’t cause vertigo Visual acuity may be reduced but patients usually adapt well Often idiopathic or linked to albinism or retinal pathology
34
Acquired Nystagmus:
Results from a vestibular disorder, neurologic lesion, or drug toxicity Often jerk-type (slow drift + fast corrective snap) May cause oscillopsia, vertigo, imbalance
35
Primary Symptom =
Vertigo (the sensation of spinning) Caused by asymmetry in vestibular input (e.g., one side underactive) Nystagmus is often the objective clinical sign that correlates with vertigo
36
📌 Not all nystagmus causes vertigo — for example:
Congenital nystagmus usually doesn’t Central nystagmus may or may not be associated with spinning
37
A 55-year-old patient presents with vertigo and spontaneous nystagmus that is vertical and does not suppress with visual fixation. What is the most likely location of the lesion? A. Right horizontal semicircular canal B. Left vestibular nerve C. Cerebellum or brainstem D. Posterior canal (BPPV)
C. Cerebellum or brainstem Vertical nystagmus + lack of suppression with fixation = central lesion.
38
Which of the following best describes a gaze stabilization exercise intended to promote VOR adaptation? A. Turn head side-to-side while following a moving target B. Focus on a letter on the wall while turning the head quickly side-to-side C. Look at a target, close your eyes, move your head, and reopen eyes D. Stand on a foam surface with eyes closed and head still
B That describes a VOR x1 exercise, designed to induce retinal slip and recalibrate VOR gain.
39
A patient experiences brief episodes of vertigo when lying down or rolling in bed. The Dix-Hallpike test triggers up-beating and torsional nystagmus. What is the most likely diagnosis? A. Vestibular migraine B. Cerebellar stroke C. Posterior canal BPPV D. Vestibular neuritis
C. Posterior canal BPPV
40
List 3 key features that differentiate peripheral from central nystagmus
Direction – Peripheral is usually unidirectional; central can be direction-changing. Fixation suppression – Peripheral nystagmus decreases with visual fixation; central does not. Accompanying signs – Central nystagmus often has other neuro signs (e.g., ataxia, diplopia); peripheral does not.
41
Which patient would most benefit from VOR substitution exercises? A. Patient with acute unilateral vestibular neuritis B. Patient with positional vertigo due to BPPV C. Patient with bilateral vestibular hypofunction D. Patient with cerebellar stroke
C Substitution strategies are used when VOR adaptation isn’t possible — common in bilateral loss.
42
Types of Physiological (Normal) Nystagmus:
These types occur in healthy individuals as part of normal visual-vestibular function. Optokinetic Nystagmus (OKN) End-Point Nystagmus Post-rotatory Nystagmus Caloric-induced Nystagmus
43
Optokinetic Nystagmus (OKN) =
cause = Visual tracking Watching stripes move past (e.g. train)
44
End-Point Nystagmus =
cause = Oculomotor fatigue Holding eyes at extreme lateral gaze (normal variant of gaze-evoked)
45
Post-rotatory Nystagmus =
cause = Labyrinth stimulation After spinning in a chair — eyes beat opposite the spin initially
46
Caloric-induced Nystagmus =
cause = Temperature Cold/warm water in ear stimulates SCCs (used for testing vestibular function)
47
Pathological (Abnormal) Nystagmus This is caused by dysfunction of:
The peripheral vestibular system (SCCs, otoliths, vestibular nerve) The central nervous system (brainstem, cerebellum, or cortical integration areas)
48
Spontaneous Nystagmus =
Eye movement at rest, not triggered by gaze or position Vestibular imbalance (e.g., vestibular neuritis)
49
Gaze-Evoked Nystagmus (GEN) =
Only appears when looking in a specific direction (not primary gaze) Cerebellar lesion, brainstem dysfunction, drugs
50
End-Point Nystagmus =
Normal horizontal jerk when looking far to one side Fatigue, normal variant of GEN
51
Triggered/Positional Nystagmus =
Brought on by head or body movement/position BPPV, central positional vertigo
52
GEN that is ___, ___, or present in ___ gaze directions is abnormal and often indicates a central lesion.
asymmetric persistent multiple
53
Physiological Nystagmus occurrence - direction - symptoms - fixation -
Only under specific conditions (OKN, end gaze) Usually symmetric and brief None Not applicable
54
Pathological Nystagmus occurrence - direction - symptoms - fixation -
At rest, with gaze, or position May be direction-changing, persistent Vertigo, imbalance, oscillopsia May or may not suppress (helps differentiate peripheral vs central)
55
Gaze-Evoked Nystagmus (GEN) Caused by:
Brainstem or cerebellar disorders (e.g., MS, stroke) Medications (anticonvulsants, sedatives, alcohol) Congenital causes Ocular muscle fatigue End-point strain (normal variant if subtle, symmetric, and only at extremes)
56
Central vs Peripheral Nystagmus Cause:
P = Inner ear (labyrinth), vestibular nerve C = Brainstem, cerebellum, cortical areas
57
Central vs Peripheral Nystagmus Direction:
P = Unidirectional, usually horizontal ± torsional C = Direction-changing with gaze OR vertical
58
Central vs Peripheral Nystagmus Fixation Suppression:
P = Yes – nystagmus lessens with visual fixation C = No – persists even when focusing visually
59
Central vs Peripheral Nystagmus Vertigo:
P = Intense spinning sensation, nausea C = May be mild or absent
60
Central vs Peripheral Nystagmus Balance:
P = Mild to moderate imbalance; able to walk C = Severe ataxia, often unable to walk unassisted
61
Central vs Peripheral Nystagmus Hearing Loss:
P = May be present (e.g., Meniere’s, labyrinthitis) C = Rare
62
Central vs Peripheral Nystagmus Other Neuro Signs:
P = None C = Often present – diplopia, dysarthria, limb ataxia, headache, numbness
63
Central vs Peripheral Nystagmus Fatigability:
P = Yes – decreases with repeated testing C = No – consistent
64
Central vs Peripheral Nystagmus Latency (with positional tests):
P = Short delay before onset C = Often immediate
65
Central vs Peripheral Nystagmus Common Conditions:
P = BPPV, vestibular neuritis, Meniere’s C = Stroke, MS, tumor, cerebellar degeneration
66
Key Red Flags for Central Nystagmus
Vertical nystagmus (especially down-beating) Direction-changing gaze-evoked nystagmus Nystagmus that doesn’t suppress with fixation Severe ataxia or falls without warning New diplopia, dysarthria, dysphagia Sudden onset imbalance with no ear symptoms 👉 These warrant immediate referral or urgent neurologic eval.
67
But not all central nystagmus = emergency!
Some patients with known central lesions (e.g., post-stroke, MS, TBI, cerebellar degeneration) may have residual central nystagmus as part of their chronic condition
68
A patient with MS and chronic direction-changing nystagmus may still benefit from:
VOR substitution exercises Gaze strategies Balance training with visual input optimization
69
Do you treat this central nystagmus? Sudden, acute onset + neuro signs
no Refer ASAP (possible stroke, MS, etc.)
70
Do you treat this central nystagmus? Known diagnosis, chronic symptoms
yes Treat as part of neuro rehab plan
71
Do you treat this central nystagmus? Unsure + red flags present
no Hold therapy and refer for clearance
72
Alexander’s Law =
describes how spontaneous nystagmus (caused by a peripheral vestibular lesion) behaves depending on gaze direction Spontaneous nystagmus becomes more intense when the patient gazes in the direction of the fast phase.
73
So, if the fast phase of nystagmus is to the left, the nystagmus will:
Be stronger when the patient looks left Be weaker when the patient looks straight ahead Be almost absent or suppressed when the patient looks right
74
Alexander’s Law applies to :
Peripheral vestibular nystagmus, especially acute cases
75
Why it happens - alexanders law:
The brain tries to rebalance input after one vestibular side suddenly underperforms (asymmetry of tonic input)
76
Let’s say your patient has a right vestibular neuritis (right side is affected):
Their brain gets less input from the right ear Brain interprets this as turning the head to the left So the eyes drift slowly to the right (slow phase), then snap quickly to the left (fast phase) That’s left-beating nystagmus Apply Alexander’s Law: Nystagmus gets worse when looking left Less noticeable in center gaze Mild or absent when looking right
77
Alexander's Law NOT seen in:
Central lesions (nystagmus doesn't follow this gaze pattern) BPPV (which causes positional, not spontaneous, nystagmus)
78
If you’re given a case with spontaneous unidirectional nystagmus that worsens in one direction of gaze and suppresses with fixation →
peripheral, and Alexander’s Law supports it.
79
Gaze Pattern in Central Lesions (Compared to Peripheral)
In central lesions, the nystagmus changes direction depending on where the patient is looking. In peripheral lesions (following Alexander’s Law), nystagmus intensity changes — but the direction stays the same.
80
➔ Peripheral =
"same direction" nystagmus, just stronger/weaker depending on gaze direction.
81
➔ Central =
"direction-changing" nystagmus depending on gaze direction.
82
21-year-old woman Acute onset vertigo + nausea Physical exam: Left-beating spontaneous nystagmus in primary gaze (looking straight ahead) Nystagmus decreased with right gaze (toward slow phase) Nystagmus increased with left gaze (toward fast phase) Brain MRI: Normal Diagnosis: Vestibular neuritis
Left-beating spontaneous nystagmus = Fast phase to the left. Fast phase always beats toward the healthy ear. Inflamed side = Right vestibular nerve (unilateral hypofunction). Vestibular neuritis affects the vestibular nerve peripherally, not the brain or cerebellum — so no central findings on MRI.
83
➔ Look toward healthy side
→ stronger nystagmus
84
➔ Look toward affected side
→ weaker nystagmus
85
After a unilateral vestibular loss (like vestibular neuritis), there's an imbalance of firing between the left and right vestibular systems =
The brain interprets this as constant head movement toward the healthy side. Gaze toward the healthy side = strengthens this error signal, so the nystagmus intensifies. Gaze toward the lesion = dampens the error signal, so nystagmus weakens. There was no hearing loss or central signs Vestibular branch only = Balance symptoms only (Neuritis)
86
If a case says "left-beating nystagmus, worsens with left gaze," you know: The ___ ear is healthy. The ___ vestibular system is impaired.
left right

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