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J Neurol (2013) 260:19921996 DOI 10.1007/s00415-013-6911-5
ORIGINAL COMMUNICATION
Dalfampridine in patients with downbeat nystagmusan observational study
Jens Claassen Katharina Feil Stanislav Bardins Julian Teufel
Rainer Spiegel Roger Kalla Erich Schneider Klaus Jahn Roman Schniepp
Michael Strupp
Received: 11 December 2012 / Revised: 28 March 2013 / Accepted: 30 March 2013 / Published online: 16 April 2013 Springer-Verlag Berlin Heidelberg 2013
Abstract We investigated the effects of dalfampridine, the sustained-release form of 4-aminopyridine, on slow phase velocity (SPV) and visual acuity (VA) in patients with downbeat nystagmus (DBN) and the side effects of the drug. In this proof-of-principle observational study, ten patients received dalfampridine 10 mg bid for 2 weeks. Recordings were conducted at baseline, 180 min after rst administration, after 2 weeks of treatment and after 4 weeks of wash-out. Mean SPV decreased from a baseline of 2.12 deg/s 1.72 (mean SD) to 0.51 deg/s 1.00 180 min after rst administration of dalfampridine 10 mg and to 0.89 deg/s 0.75 after 2 weeks of treatment with dalfampridine (p \ 0.05; post hoc both: p \ 0.05). After a wash-out period of 1 week, mean SPV increased to2.30 deg/s 1.6 (p \ 0.05; post hoc both: p \ 0.05). The VA signicantly improved during treatment with dalfampridine. Also, 50 % of patients did not report any side effects. The most common reported side effects were abdominal discomfort and dizziness. Dalfampridine is an
effective treatment for DBN in terms of SPV. It was well-tolerated in all patients.
Keywords Clinical Neurology Neuro-Ophthalmology
Neurotology Downbeat nystagmus Dalfampridine
Introduction
The most common form of persistent acquired nystagmus in the primary position is downbeat nystagmus (DBN), which is characterized by an upward drift followed by a fast correcting saccade in a downward direction [1]. Patients report oscillopsia, blurred vision and reduced VA as well as gait or stance difculties [1]. There is increasing evidence that DBN is caused by an impaired function of cerebellar Purkinje cells (PC) [24] leading to a predominance of cells with downward on-direction [5] and an inhibition of superior vestibular nuclei neurons [3].
The 4-aminopyridine (4-AP) has already been used successfully in patients with DBN [69]. Animal studies
J. Claassen, K. Feil contributed equally to the article.
J. Claassen (&) K. Feil S. Bardins J. Teufel R....