Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Episodic ataxia ?
    ### Response:
    Episodic ataxia refers to a group of related conditions that affect the nervous system and cause problems with movement. It is characterized by episodes of poor coordination and balance (ataxia). During these episodes, many people also experience dizziness (vertigo), nausea and vomiting, migraine headaches, blurred or double vision, slurred speech, and ringing in the ears (tinnitus).
    