38% of migraine sufferers experience auras. Not all migraines involve auras, only 20% do. When present, auras last about 30 minutes; a migraine usually follows within 10 minutes. 20% of auras don’t become a migraine.
Over 50 aura-symptoms have been described. Visual auras are by far the most frequent, although weakness, dizziness, numbness/tingling, and speech difficulties, are common.
Studies show migraines result from damage to local brain cells. This causes altered function of the brain-region involved. If damage is severe enough, we perceive it consciously and aura results.
The damaged brain cells also release a host of biochemicals, and if damage is sufficient biochemicals, are released to turn on local pain sensors (nociceptors) which results in us experiencing the pain we know as the migraine headache.
So how are brain cells damaged? The brain is the most energy hungry organ in the body. It requires 10 times more oxygen than the rest of the body (Clarke & Sokoloff 1999). The brain is exquisitely sensitive to anything that hampers energy production including lack of oxygen and when brain cells can’t make enough energy, they are easily damaged.
In the damaged, some neurons stop working (i.e., stop producing their normal electrical signals). In migraine, the area within which damage happens spreads like a wave across the cortical surface of the brain, involving ever more brain cells. This phenomenon is called a cortical spreading depression (CSD)
The type of aura we get depends upon the region in which damage occurs. The area of the brain which controls vision is at the back of the head. It is known as Brodmann’s area 17. The visual cortex has the highest neuronal density of any brain region and the lowest relative density of supporting cells called astrocytes that protect brain cells from CSD. It is the brain region most sensitive to energy deprivation and thus migraine-auras are mostly visual because in most people the brain-cell-damage that initiates a CSD occurs in the vulnerable visual cortex. The simple reason migraine-auras are varied is that symptoms depend upon the brain region in which damage and CSD starts-and on where the damage wave travels to.
Article Written + Submitted by:
Andreas Klein Nutritionist + Remedial Therapist from Beautiful Health + Wellness
P: 0418 166 269