The effect of 3,4-diaminopyridine on the patients with hereditary pure cerebellar ataxia

Abstract

Background Downbeat nystagmus (DBN) is often seen in patients with pure cerebellar type of spinocerebellar ataxia (SCA) like spinocerebellar ataxia type 6 (SCA6). DBN frequently presents with other cerebellar symptoms such as postural imbalance or ataxia. A potassium channel blocker 3,4-diaminopyridine (3,4-DAP) has been reported to reduce DBN by increasing the excitability of Purkinje cells. Objective The objective of this study is to determine whether 3,4-DAP has a beneficial effect on DBN along with postural imbalance and ataxic symptoms in 10 patients with SCA6 and five patients with chromosome 16q22.1-linked autosomal dominant cerebellar ataxia (16q-ADCA). Results The patients took 20 mg of 3,4-DAP twice a day for a week. DBN was observed in seven patients with SCA6 and two with 16q-ADCA. Although 3,4-DAP significantly reduced DBN ( P < 0.05), other ataxic symptoms did not improved. However, 3,4-DAP showed benefit in two patients with oscillopsia. Conclusion 3,4-DAP may be effective on DBN and oscillopsia, although it was not proved to be effective on other symptoms of ataxia in SCA patients.