Cerebellar ataxia is called cerebellar ataxia when the patient’s muscle tone is reduced and the coordination of random movements is disturbed due to some cause of cerebellar damage. Clinical classification 1. trunk ataxia Trunk ataxia (postural cerebellar ataxia), mainly manifests as the patient’s gait and posture (standing and sitting) balance disorders, such as standing instability, sitting instability, walking instability, Romberg’s sign (eye opening and closing) positive (unstable), upper limb ataxia is not obvious, no nystagmus. The localization diagnosis is mainly in the cerebellar earthworm (primordial cerebellum) which is damaged. It can be seen in ADCA type III, ataxia capillaris, etc. 2, limb coordination ataxia limb coordination ataxia (motor cerebellar ataxia), mainly manifested as the balance of the patient’s limbs to complete various movements, such as finger-nose test, inaccurate heel-knee-shin test, poor distance discrimination, poor alternating movements, misfinger test bias to the diseased side, nystagmus is more common (coarse), gait instability, etc.. Ataxia is generally more severe in the upper extremities than in the lower extremities. The localization diagnosis is mainly in the cerebellar hemisphere (neocerebellum) is damaged. 3.All-cerebellar ataxia All-cerebellar ataxia, the lesion is located in the primordial cerebellum, neocerebellum, cerebellar nuclei, cerebellar afferent (out) fibers, the clinical manifestation is ataxia of trunk, limbs and gait, which can be seen in ADCAI type and so on.