1. 168-6 Downbeat Nystagmus PAN

2. No nystagmus initially in primary gaze A period of downbeat nystagmus in central gaze A period of periodic alternating nystagmus No nystagmus on upgaze. Eye Movements

3. Periodic alternating nystagmus is due to a lesion of the cerebellar nodulus and uvula. Pathogenesis

4. Leigh RJ, Zee DS. The Neurology of Eye Movements 4th Edition. Oxford University Press, New York 2006 with permission Clinical Features of Acquired Periodic Alternating Nystagmus

5. Leigh RJ, Zee DS. The Neurology of Eye Movements 4th Edition. Oxford University Press, New York 2006 with permission. Acquired PAN

6. Arnold Chiari malformation Ataxia telangiectasia Cerebellar degeneration Creutzfeldt-Jakob disease Acquired PAN

7. Hepatic encephalopathy Lithium toxicity Multiple Sclerosis Spinocerebellar ataxia Following visual loss

8. The authors observed a periodic downbeat nystagmus with a cycle of 3 minutes 30 seconds, beating downward for a period of 90 seconds every 2 minutes. It lasted 86 hours in a patient with severe hypomagnesemia associated with complications from scleroderma. There was no lesion on brain imaging, and an EEG performed during the nystagmus was normal, indicating that the most likely explanation for this periodic nystagmus is metabolic. This form of nystagmus may have resulted from severe hypomagnesemia, possibly associated with thiamin deficiency. Periodic Downbeat Nystagmus DuPasquier, R. et al. Neurology 1998; 51:1478 – 1480.

9. Keane JR. Periodic alternating nystagmus with downward beating nystagmus. Arch Neurol 1974; 30:399-402. Matsumoto S, Ohyagi Y, Inoue I, et al. Periodic alternating nystagmus in a patient with MS. Neurology 2001;56:276-277. References

10. http://www.library.med.utah.edu/NOVEL