Tsunemi_2010_J.Neurol.Sci_292_81

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 20mg 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.