Nystagmus

NYSTAGMUS 
🔃purely torsional nystagmus:lesion of brainstem /vestibular nuclei .Ex:syringomyelia 🔃
Vertical downbeats: lesion at craniocervical region/degenerative lesion of cerebellum .Ex.:Arnold-chiari malformation 
Vertical upbeat nystagmus:lwsion at junction of pons and medulla/pons and mid brain .
➰Pendular nystagmus:
Congenital/acquired
Ex:multiple sclerosis(acquried)➰
Pendular nystagmus may also disconjugate
i.e .vertical in one eye and horizontal in other eye .