Midterm Exam Nystagmus Flashcards
Define Nystgmus
Involuntary rhythmic oscillation of the eye
- many different types
Nystagmus have a ____ & ____ phase
Nystagmus has a slow & fast phase
Direction of nystagmus is determined by what
Direection of nystgmus is determined by the fast phase
RB,LF, UB or DB
How do you determine the strength?
The strength is measured by the slow phase, slope
Slow phase is generated by what
The slow phase is generated by the vestibular system
- tells you how the vestibular system is operating
Fast phase is generated by what
Fast phase is genered by the central system
- does not tell us about teh vestibualr system
The slow phase is driven by
The slow phase is driven by the ears (peripheral vestibular)
The fast phase is driven by
The fast phase is driven by the CNS (Central)
Nystgmus beats away from what
nystgmus beats away from the affected ear.
What is an ENG/VNG
- primarly 2-D recordings horizontal (H) & Vertical (V) movements
- We can recoed vision denied & vision allowed
Horizontal
Name the type of nystgmus
Left beating Nystgmus
* For horizontal lay your had on slow phase
- left hand for left beating
Horizontal
Name the type of nystgmus
Right beating nystgmus
* For horizontal lay your had on slow phase
- right hand for right beating
Vertical
Name the type of nystgmus
Down beating nystgamus
- For vertical left is down & right is up
- Up tight, down low
Vertical
Name the type of nystgmus
Up beating nystgmus
Down beating nystgamus
- For vertical right is up & left is down
- Up right, down low
What is ENG/VNGs good at capturing?
LB,RB,UB,DB nystgamus - good
- Not torsional, 2-d systems do not capture well but video recodign to infer from
What does torsional nysytagmus look like on an ENG/VNG
You will have nystgmus in both the horizontal and verticle channels
Head turns right -
Utriculpetal for right ear -
left lateral rectus =
Right medial rectus =
Utriculpetal for left ear -
right lateral rectus =
left medial rectus =
Head turns right - enodolymph move left
Utriculpetal for right ear - excitatory
left lateral rectus = contracts
Right medial rectus = contracts
Utriculpetal for left ear - inhibitory
right lateral rectus = relaxes
left medial rectus = relaxes
Head turns left -
Utriculpetal for right ear -
left lateral rectus =
Right medial rectus =
Utriculpetal for left ear -
right lateral rectus =
left medial rectus =
Head turns left - enodolymph move right
Utriculpetal for right ear - inhibitory
left lateral rectus = relaxes
Right medial rectus = relaxes
Utriculpetal for left ear - excitatory
right lateral rectus = contracts
left medial rectus = contracts
name the two types of nystgmus
Pendular Nystagmus
Jerk Nystgmus
Name Nystagmus
The speed of motion of the eyes is the same in both directions
Pendular Nystagmus
Define Pendular Nystagmus
The speed of motion of the eyes is the same in both directions
Name Nystagmus
There is slow & fast phase. The eyes move slowly in one direction and then fast in the other
Jerk Nystagmus
Jerk Nystgmus
There is slow & fast phase. The eyes move slowly in one direction and then seem to jerk back in the other direction.
Name the Nystagmus
Pendular Nystagmus
No distinct fast and slow phases (sinusoidal pattern)
Name the Nystagmus
Torsional/Rotary Mixed Nystagmus
central or mixed which can indicate
peripheral issues
Name the Nystagmus
Jerk Nystagmus
Horizontal → typically congenital
Vertical → acquired cerebellar disease
Types of Jerk Nystagmus
Can be Down beating, up beating, left beating or right beating
the amplitude of jerk nystagmus increases when looking in the direction of the fast phase.
alexanders law
This nystagmus intenity increases with gaze towards the fast phase
right-beating nystagmus.
When looking right (toward fast phase) → nystagmus is stronger.
When looking left (away from fast phase) → nystagmus is weaker.
Aquired Horizontal Jerk Nystagmus
- Obeys Alex’s law
- Peripheral
- Left beating Nystagmus
- Central (eyes closed)
- But if you vision allowed and
- nytagmus got better = peripheral
- ## Nystagmus got worse = central
Left beating nystagmus
Normal
- The patient is showing square wave jerks with eyes closed.
- Some normal individuals display square wave jerks, although their peak-to-peak amplitudes rarely exceed 5 deg.
Abnormal. There is a right-beating nystagmus, with slow phases greater than 6 deg/sec.
Left beating nystagmus
- right side affected
- Peripheral - suppresed w/vision
Left beating
- right affected
- peripheal
Ask - confused since there was central Nystgamus
- CNS disorder
- The slow phase velocity of the nystagmus does not increase when the patient closes eyes.
- The nystagmus is not suppressed by visual fixation.
downbeating nystagmus.
* Central
* Downbeating nystagmus is generally considered to be evidence of a lesion in the cerebellum or lower brainstem.
right-beating nystagmus in the sitting and supine positions and stronger, persistent right-beating nystagmus in the right-ear-down position.
* Nystagmus was unchanged when the patient was turned on the right side, so it is not due to neck torsion.
* Assume Peripheral but would need calorics to know forsure
- right-beating nystagmus with eyes closed that meets criteria “b” and “d”.
- “spontaneous nystagmus”, since its intensity is unaltered by changes in head position.
- assume Periheral would need calorics to know for sure
positional nystagmus with eyes closed
* Geotropic
* right-beating in the right-ear-down position (geotropic) and left-beating in the left-ear-down position.
* Non-localizing
- Direction-fixed positional nystagmus that is in three or more positions.
- Non-localizing.
- If caloric asymmetry = peripheral
- If Calorics abnormal = unclear
- direction-changing nystagmus in a single head position.
- Central
- Basilar Insufficiency - due to neck torsion
- This patient has a right-beating nystagmus with eyes closed that is strong enough to be abnormal. It is absent when the patient is placed whole body right so it must be due to neck torsion.
- geotropic nystagmus with eyes open only.
- Central
- This nystagmus does not enhance or increase with eyes closed. In fact the nystagmus disappears with eyes closed.
All tracings in Same position
PAN - Periodic Alternating Nystagmus
Positonal Testing
- Geotropic
- HC BPPV
- Right side affected
- 8 left and 10 right
affected side is the stronger side
Normal
what is gaze evoked nystagmus
Gaze-evoked nystagmus (GEN) is a type of nystagmus that occurs when the eyes are held in an eccentric (off-center) position and is not present in primary (center) gaze.
what is a type of nystagmus that occurs when the eyes are held in an eccentric (off-center) position and is not present in primary (center) gaze.
Gaze - evoked nystagmus
what are the three basic types of nystagmus that are considered as normal (physiological) phenomena?
- Fatigue Nystagmus
- Unsustained end point nystagmus
- Sustained end point nystagmus
