Episodic ataxia (EA) is a clinically heterogeneous group of disorders that are characterized by recurrent spells of truncal ataxia and incoordination lasting minutes to hours. Most have an autosomal dominant inheritance pattern. To date, 8 subtypes have been defined according to clinical and genetic characteristics, and five genes are known to be linked to EAs. Both EA1 and EA2, which are caused by mutations in KCNA1 and CACNA1A, account for the majority of EA, but many patients with no identified mutations still exhibit EA-like clinical features. Furthermore, genetically confirmed EAs have mostly been identified in Caucasian families. In this article, we review the current knowledge on the clinical and genetic characteristics of EAs. Additionally, we summarize the phenotypic features of the genetically confirmed EA2 families in Korea.

In view of more rapid resolution of static vestibular imbalance after VN, evaluation of the dynamic vestibular imbalances may provide more useful information for underlying vestibulopathy, especially in the compensated phase. The different temporal profiles ofdynamic vestibular recovery may reflect different chronological characteristics of vestibular compensation according to stimulus frequency. Direction reversal of HSN and VIN during follow-up suggests that lateralization of VNbased on the direction of these nystagmus should be considered in the context of disease phase.

We propose that head-shaking nystagmus in lateral medullary infarction is due to unilaterally impaired nodulouvular inhibition of the velocity storage. This proposal is consistent with the results of neuroanatomic studies that demonstrate that Purkinje cells controlling velocity storage in the nodulus and ventral uvula project to the caudal or middle portion of the vestibular nuclei, whereas those subserving visual-vestibular interactions in the flocculus project to the more rostral portion.

This study provides Class I evidence that barbecue rotation and Gufoni maneuvers are effective in the treatment of geotropic HC-BPPV.