Nystagmus Flashcards
What does a cerebellar nystagmus look like?
Coarse, horizontal nystagmus. Fast component towards the side of the lesion
What are the other cerebellar eye signs to look for other than nystagmus? (advanced q)
Broken pursuit, ocular dysmetria- hypo- or hypermetric saccades.
What does a peripheral vestibular nystagmus look like?
Mixed horixontal-rotatory or purely horizontal. Never vertical.
Always uni-directional, with the fast component away from the side of the lesion.
What does a central vestibular nystagmus look like?
Horizontal, vertical, rotatory or mixed. Usually bi-directional, may be uni-direction
What is a unidirectional nystagmus?
Nystagmus only increases on looking to one side
What is a bidirectional nystagmus?
Nystagmus increases on looking to both sides i.e. fast component to the left on left gaze and fast component to the right on right gaze.
What does Alexander’s law state?
Peripheral vestibular nystagmus: The nystagmus increases towards the direction of the fast component
Central vestibular nystagmus: The fast component chages with the direction of gaze, i.e. left on left gaze, right on right gaze and up on upward gaze.
What symptoms may be associated with peripheral vestibular nystagmus?
Vertigo, tinnitus and deafness (not present in central causes)
What are some causes of a peripheral vestibular nystagmus?
Labyrinthitis Meniere's disease Acoustic neuroma Degenerative middle ear disease BPPV
What are some causes of a central vestibular nystagmus?
Vascular: Brainstem infarction Neoplastic: Brainstem tumours Infective: Meningoencephalitis Toxins: ETOH Demyelination Syringobulbia
What is a physiological nystagmus?
“End point nystagmus”- occurs when a person looks beyond 40 degrees. Low amplitutde, horizontal nystagmus with rapid component directed laterally. No other ocular abnormalities are found
