Migraine Headache

Migraine Aura is quite annoying!

Migraine Aura is a visual symptom that occurs due to an alteration in the brain system. It serves as a warning sign for the people suffering from migraine informing them about the onset of headache before it actually occurs. A patient normally sees shining zigzag lines or blot out of vision. The patient may also experience other symptoms related to the brain like weakness, unsteadiness, altered consciousness or numbness of hands and face.

Auras are usually visual, but may also be motor, verbal or sensory disturbances. A visual aura resembles a chemical or electrical wave that moves across the brain's visual cortex. All the visual signals are processed by a part of the brain called the visual cortex. As this wave spreads, the patient may experience visual hallucinations. It is a disorder which reoccurs with time.

It develops gradually over 5 to 20 minutes and lasts for less than 60 minutes. This is followed by headache with migraines' symptoms.  Sometimes headache lacks or is completely absent the symptoms of migraine. This condition is known as migraine aura without headache.

The aura occurs because of the changes that take place in the outer layer of the brain, that is, the cortex. The decline in the activity of the nerve cell is responsible for the typical pattern of development of the aura. Migraines may progress through four stages:
  • Prod Rome
  • Aura
  • Attach
  • Post-drome

However, all the four stages are not experience by everyone. About 60% of the patients go through the predrome stage. About 20 percent of the people experience a distinct “warning sign” in the second phase, called the migraine aura.

The decline in the nerve cell activity is responsible for the pattern of the particular aura. In migraine aura, symptoms build up in one region of the body and slowly and gradually move to other visual regions. For example, the patients first see a black spot surrounded by bright zigzag line or flashing lights in their field of vision. The size of this black spot increases over a period of few minutes. Another typical feature of migraine aura is loss of vision with zigzag lines and flashing light. The blackout of vision is because of the depressed nerve activity.

Auras may vary from person to person. People may experience bright spots or flashes. A sensory aura also occurs in some cases and starts as numbness or a tingling effect in one limb for over 10-20 minutes. This sensation sometimes spread to one side of the face and the tongue.

These internal and external events stimulate the various nerves of the brain. This stimulus is then relayed to one of the brain's nerve centers and from there, another set of nerve impulses are sent to the cortex which results in the aura. The biochemical phenomenon that leads to headache also begins in these brain centers.