Abstract: We describe a patient with downbeat nystagmus (DBN) evoked only by eye closure. Brain and spinal cord magnetic resonance imaging revealed a T2 paramedian lesion in the left lower basis pontis and other white matter lesions consistent with multiple sclerosis. One potential mechanism for DBN in this case involves transverse ephaptic spread of excitation from areas that subserve coordinated lid closure to the decussating ventral tegmental tract.
Departments of Neurology (JL, BS, LC), Neuroradiology (DP), and Otorhinolaryngology (MA, AP), Coimbra University Hospital Center, Coimbra, Portugal.
Address correspondence to João Lemos, MD, Department of Neurology, Coimbra University Hospital Center, Praceta Professor Mota Pinto, Coimbra 3000-075, Portugal; E-mail: firstname.lastname@example.org
The authors report no conflicts of interest.
Presented as a poster at the 39th Annual NANOS Meeting, February 11–16, 2013, Snowbird, UT.
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