What causes a pre migrain aura/ visual disturbance but no migraine headache?

Good Question: The causes of migraine aura without headache are the same as with headaches including stress, foods, sleep patterns, hormonal changes and others. Why one does or does not have a headache after the aura is not yet understood. The aura is thought to be a electrical or chemical activity in the visual area of the brain.

Neurologic disturb: Unilateral episodic throbbing neurologic disturbance or deficits occur before headache but if you know how to avoid the severe headache by lifestyle modification or taking your rx before the attack it will be aborted.