SHORT REPORT

4-aminopyridine restores visual ocular motor function in upbeat nystagmus

S Glasauer^*, R Kalla^*, U Büttner, M Strupp and T Brandt

Department of Neurology, University of Munich, Germany

Correspondence to:
Correspondence to:
Dr S Glasauer
Department of Neurology, Klinikum Grosshadern, Marchioninistrasse 23, 81377 Munich, Germany; sglasauer{at}nefo.med.uni-muenchen.de

The effect of the potassium channel blocker 4-aminopyridine (4-AP) on spontaneous upbeat nystagmus (UBN) was investigated with the search coil technique during fixation in different gaze positions and smooth pursuit in a patient before and after ingestion of 10 mg 4-AP. UBN was reduced from 8.6 deg/s to 2.0 deg/s by 4-AP causing subjective relief from distressing oscillopsia, and impaired upward smooth pursuit was restored (gains: before medication 0.38; after medication 0.86). In the dark, UBN was slightly stronger and not affected by 4-AP. We propose that 4-AP improved the function of cerebellar pathways that mediate gaze holding and smooth pursuit by intensifying the excitability of cerebellar Purkinje cells.

Abbreviations: 4-AP, 4-aminopyridine; DBN, downbeat nystagmus; UBN, upbeat nystagmus

Keywords: upbeat nystagmus; 4-aminopyridine; potassium channel blocker; smooth pursuit; case report

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This article has been cited by other articles:

• Strupp, M., Brandt, T. (2009). Review: Current treatment of vestibular, ocular motor disorders and nystagmus. Therapeutic Advances in Neurological Disorders 2: 223-239 [Abstract]  
• Kalla, R., Glasauer, S., Buttner, U., Brandt, T., Strupp, M. (2007). 4-Aminopyridine restores vertical and horizontal neural integrator function in downbeat nystagmus. Brain 130: 2441-2451 [Abstract] [Full Text]