It is common for a patient with migraine to experience symptoms other than headache. These can occur at any point during the migraine: before, during and after an attack. One symptom that can cause alarm is the aura. Just under a quarter of people with migraine experience this symptom. These symptoms typically occur before the headache phase begins. Some people experience aura without the headache occuring (acephalgic migraine). Aura sympoms can be visual sensory or affect an individuals strength (motor aura).
This is the most common and well-studied type of aura. The symptoms can be quite alarming and patients often and understandably feel anxious and worried when they experience this for the first time. This can take many forms, but typically, patients see a zig-zag line starting on one side which moves across the field of vision before fading away. Patients may also see sparkling or flashing lights or diamond-shaped small lights, which some people liken to looking into a kaliedoscope.
The symptoms usually change in shape, size and location. If the symptoms are stationery, for example flashing spots or zigzags which do not move or grow in size, they are less likely to represent migraine aura.
Visual aura generally lasts between 5 and 60 minutes in a typical patient although some patients may have peristsent visual symptoms. Sometimes after these symptoms go away, there may be dark holes in the vision where patients are not able to see (scotoma).
This can be in the form of tingling (or pins and needles) or numbness (a dead feeling in part of a limb). Usually patients are able to note the progression of symptoms as it starts in one part of the body and moves up or down. For example, if the feeling starts in the hand, it will move up the arm and not involve the entire limb at one time.
Speech and language can also be affected causing ‘word finding difficulty’ or slurring of words.
Another form of sensory aura is found in “vestibular migraine” where a feeling of room spinning dizziness or vertigo is experienced.
Motor aura (Hemiplegic Migraine)
This is a much rarer form of aura and consists of motor weakness of part of the body. Many patients with this type of aura have other members in the family who experience similar symptoms (called familial hemiplegic migraine) although it can also occur without a family history (sporadic hemiplegic migraine). Although feelings of numbness (often with a limb feeling “dead”) are common, genuine weakness on one side suggestive of hemiplegic migraine is much less common.
What causes aura?
Migraine aura has been described (and drawn in pictures) since at least 1870. In the 1940s, a gentleman named Lashley documented his own visual aura as it happened. He realised his symptoms were likely due to an electrical disturbance across his brain cortex which is nown as Cortical Spreading Depression (CSD). CSD is essentially a wave of hyper-activity which spreads across the nerve cells of the brain (like water rippling across a pond). The form in which the resulting aura takes is dependent on which area the rippling effect occurs in. The exact mechanisms for CSD are not fully understood.
How do you treat migraine aura?
Fortunately, most aura symptoms last for a short period of time. Triptans are not usually effective during the aura phase but some people find Aspirin can be helpful. It is important to avoid any activities that you feel may be dangerous whilst your senses are somewhat impaired.
If the aura symptoms are frequent and disturb your life significantly, there are several preventive medications that can be used to reduce the frequency and the duration of the aura attacks.
Migraine aura and stroke
It has been shown that patients with migraine aura have a slightly increased risk of having a stroke. This is a small risk but can increase further if other risk factors are present such as smoking, high blood pressure, high cholesterol, and being over-weight. So, it is important that patients stop smoking, get their blood pressure, cholesterol and glucose levels checked regularly and maintain a healthy lifestyle and body weight. Another thing that can increase the chances of stroke in these patients is the use of the combined contraceptive pill: this should be avoided by female patients with migraine aura. There are other hormonal options available for contraception. It is important to note that use of oestrogen containing HRT is allowed in patients with migraine and aura.
By Dr Jessica Briscoe, Headache Specialist.
This information is provided as a general guide only and is not a comprehensive overview of prescribing information. If you have any queries or concerns about your headaches or medications please discuss them with your GP or book an appointment to see a Headache Specialist at the National Migraine Centre.