title: Downbeat nystagmus elicited by eyelid closure.
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.
authors.affiliation: Departments of Neurology (JL, BS, LC), Neuroradiology (DP), and Otorhinolaryngology (MA, AP), Coimbra University Hospital Center, Coimbra, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Lemos
authors.forename: Daniela
authors.initials: D
authors.lastname: Pereira
authors.forename: Margarida
authors.initials: M
authors.lastname: Amorim
authors.forename: Beatriz
authors.initials: B
authors.lastname: Santiago
authors.forename: António
authors.initials: A
authors.lastname: Paiva
authors.forename: Luís
authors.initials: L
authors.lastname: Cunha
mesh_terms: D000328:Adult; D005133:Eye Movements; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000473:pathology*; D017557:Ventral Tegmental Area / Q000473:pathology*; D014741:Video Recording; D014792:Visual Acuity / Q000502:physiology