Posterior communicating artery aneurysm causing CN III palsy
Multiple nerve involvement
• Cavernous sinus syndrome! • Superior orbital fissure syndrome
Cavernous sinus syndrome • Association with ! – other cranial nerve involvement: 4, 5, 6 CN ! – oculosympathetic paralysis! – Opthalmic branch of trigeminal nerve!
• Tend to be partial; alls muscles innervated are not equally involved
Superior orbital fissure syndrome
CN 3, 4, 6, V1 !30
Superior orbital fissure syndrome • Involve CN 3, 4, 6 and V1 CN 5 distribution +/oculosympathetic paresis without anhydrosis! • May exopthalmos due to blockade of the opthalmic veins! • Blindness due to extension of the pathologic process to involve the optic canal
A patient with diplopia for 1 week with gait ataxia and areflexia
Dx. Miller Fisher syndrome in a patient with polyneuropathy, all CN can be involved causing total ophthalmoplegia
Interneuclear lesion Horizontal
Interneuclear ophthalmoplegia (INO): MLF lesion! Bilateral INO : Bilateral MLF lesion! One and a half syndrome: PPRF lesion + MLF lesion
Commonly peripheral vestibular organ dysfunction: labyrynthitis, meniere’s disease
A schematic illustration of nystagmus waveforms
(A) pendular nystagmus
(B) an accelerating velocity exponential slow phase jerk nystagmus (CN) (C) a decelerating exponential slow phase jerk nystagmus (MLN) (D) a linear or constant velocity slow phase jerk nystagmus (MLN) In (A) a slow phase is followed by a slow phase while in (B)–(D) a slow phase is followed by a fast phase
Pendular nystagmus: is central (brainstem/ cerebellum)!
Jerk nystagmus: !
linear (constant velocity) slow phase: peripheral vestibular dysfunction!
slow phase has decreasing velocity exponential: brainstem neural integrator, cerebellar!
slow phase has increasing velocity exponential: central in origin (usual form of congenital nystagmus)
A woman with periodic vertigo occur when changing position
Case study: a boy with subacute dizziness
Disconjugate eyes: diplopia
conjugate eye movement!
Saccadic system !
Visual perception system! Visual loss !
Counter rolling system: VOR, Ocular fixation system