Sudden vertigo 1-2s in the brain may be caused by the following problems: 1. Severe stenosis of the cerebral blood vessels may exist in the patient, which may easily induce cerebral vasospasm when the patient is tired or cold, or sleep deprivation, and may lead to sudden interruption of blood flow in the stenosed parts of the patient, causing sudden vertigo 1-2s in the patient. 2. Positional hypotension may be caused by this condition, which is seen when the patient is lying down or squatting and gets up suddenly. This condition may be caused by postural hypotension, which may occur when the patient is lying down or squatting and suddenly getting up. 1-2s of transient vertigo may be accompanied by blackness in front of the eyes, blurred vision, and blurred vision. 3. 1-2s of sudden vertigo in the brain may also be a manifestation of brain nerve dysfunction, for example, the patient does not sleep for a long time or stays up late causing brain nerve dysfunction, which may manifest as 1-2s of sudden vertigo, and even the patient may feel that his head is blank.