Before a stroke occurs, patients usually have some aura symptoms, such as transient weakness or numbness of one limb, transient numbness of one side of the face or crookedness of the mouth; transient slurred speech or difficulty in understanding speech; transient staring of both eyes to one side; transient loss or blurring of vision in one or both eyes; transient disturbance of consciousness or convulsions; transient dizziness and headache, etc. These symptoms are likely to be transient ischaemic attack. However, there are also patients who may suddenly develop a series of symptoms of cerebral infarction or cerebral haemorrhage without any symptoms. These precursors to a stroke should be seen by a doctor promptly.