The common diseases in neurology include cerebrovascular diseases, infectious diseases of the central nervous system, spinal cord lesions, demyelinating diseases of the central nervous system and demyelinating diseases of the peripheral nervous system, as well as epilepsy and dementia. Clinically common cerebrovascular diseases include cerebral hemorrhage, cerebral infarction, and subarachnoid hemorrhage. Patients usually have an acute onset and can present with headache, dizziness, balance disorders, ataxia, as well as limb sensory impairment, motor dysfunction, and possibly speech dysfunction. Some patients can present with seizures and also psychiatric symptoms, and cranial CT examinations can clarify the diagnosis. Infectious diseases of the central nervous system, clinically common are encephalitis and meningitis. Encephalitis is caused by viral infection, and meningitis is caused by bacterial infection. Demyelinating diseases of the central nervous system are clinically common, including multiple sclerosis. Peripheral nerve demyelinating disorders are clinically common as Greenbrier syndrome. In case of muscle diseases, myasthenia gravis is clinically common, etc.