An aura is a perceptual disturbance experienced by some with migraines or seizures. The aura stage precedes a seizure in epilepsy but can happen at any stage of a migraine. It often manifests as the perception of a strange light, an unpleasant smell, or confusing thoughts or experiences. Some people experience aura without a subsequent migraine or seizure (see silent migraine). Auras vary by individual experience; some people experience smells, lights, or hallucinations. Less known symptoms of the eye include disturbances, where the eyes roll in the back of the head caused by photosensitivity. A sufferer of this type of aura may experience tearfulness of the eyes and uncontrollable sensations of light followed by reduced symptoms after approximately 20 minutes; it is the rarest type of aura.
When occurring, auras allow people who have epilepsy time to prevent injury to themselves and/or others. The time between the appearance of the aura and the migraine lasts from a few seconds up to an hour. The aura can stay with a migraine sufferer for the duration of the migraine; depending on the type of aura, it can leave the person disoriented and confused. It is common for migraine sufferers to experience more than one type of aura during the migraine. Most people who have auras have the same type of aura every time.
Auras can also be confused with sudden onset of panic, panic attacks or anxiety attacks creating difficulties in diagnosis. The differential diagnosis of patients who experience symptoms of paresthesias, derealization, dizziness, chest pain, tremors, and palpitations can be quite challenging.
|Artist's depiction of zig-zag lines appearing as part of a migraine aura phenomenon|
An epileptic aura is the consequence of the activation of functional cortex by abnormal, unilateral, and brief neuronal discharge. In addition to being a warning sign to an upcoming seizure, the nature of an aura can give insight into the localization and lateralization of the seizure or migraine.
Not everyone experiences an aura with a seizure, but the most common auras include motor, somatosensory, visual, and auditory symptoms. The activation in the brain during an aura can spread through multiple regions continuously or discontinuously, on the same side or to both sides.
Auras are particularly common in focal seizures. If the motor cortex is involved in the overstimulation of neurons, motor auras can result. Likewise, somatosensory auras (such as tingling, numbness, and pain) can result if in the somatosensory cortex. When the primary somatosensory cortex is activated, more discrete parts on the opposite side of the body and the secondary somatosensory areas result in symptoms ipsilateral to the seizure focus.
Visual auras can be simple or complex. Simple visual symptoms can include static, flashing, or moving lights/shapes/colors caused mostly by abnormal activity in the primary visual cortex. Complex visual auras can include people, scenes, and objects which results from stimulation of the temporo-occipital junction and is lateralized to one hemifield. Auditory auras can also be simple (ringing, buzzing) or complex (voices, music). Simple symptoms can occur from activation in the primary auditory cortex and complex symptoms from the temporo-occipital cortex at the location of the auditory association areas.
An aura sensation can include some or a combination of the following:
Anomalous experiences, such as so-called benign hallucinations, may occur in a person in a state of good mental and physical health, even in the apparent absence of a transient trigger factor such as fatigue, intoxication or sensory deprivation.
The evidence for this statement has been accumulating for more than a century. Studies of benign hallucinatory experiences go back to 1886 and the early work of the Society for Psychical Research, which suggested approximately 10% of the population had experienced at least one hallucinatory episode in the course of their life. More recent studies have validated these findings; the precise incidence found varies with the nature of the episode and the criteria of "hallucination" adopted, but the basic finding is now well-supported.ICHD classification and diagnosis of migraine
The classification of all headaches, including migraines, is organized by the International Headache Society, and published in the International Classification of Headache Disorders (ICHD). The current version, the ICHD-3 beta, was published in 2013.The first category within the ICHD is Migraine. Migraines in general are considered to be a neurological syndrome. It is estimated that 11% (303 million) of the global population, including 43 million Europeans and 28 million Americans, experience migraines.Migraine Aura Foundation
The Migraine Aura Foundation (MAF) is a non-profit organization based in Germany. MAF runs a website providing access to medical information and material that helps migraine patients to recognize and understand their neurological symptoms during migraine, and thus to assume greater responsibility for their healthcare.Paroxysmal dyskinesia
The paroxysmal dyskinesias (PD) are a group of movement disorders characterized by attacks of hyperkinesia with intact consciousness. Paroxysmal dyskinesia is a rare disorder, however the number of individuals it affects remains unclear. There are three different subtypes of PD that include paroxysmal kinesigenic dyskinesia (PKD), paroxysmal non-kinesigenic dyskinesia (PNKD), and paroxysmal exercise-induced dyskinesia (PED). Other neurological diseases have similar symptoms to PD, such as epilepsy and Parkinson's. The different subtypes make accurate and quick diagnosis of PD challenging. Thus, PD is often under reported and misdiagnosed, making it difficult to accurately study its prevalence in human populations. Onset of PD is usually in late childhood to early adolescence. New drug regimens help treat symptoms of PD, but no cure for the disorder is known.Scintillating scotoma
Scintillating scotoma, also called visual migraine, is a common visual aura preceding migraine and was first described by 19th-century physician Hubert Airy (1838–1903). It may precede a migraine headache, but can also occur acephalgically (without headache). It is often confused with retinal migraine, which originates in the eyeball or socket.Vertiginous epilepsy
Vertiginous epilepsy is infrequently the first symptom of a seizure, characterized by a feeling of vertigo. When it occurs there is a sensation of rotation or movement that lasts for a few seconds before full seizure activity. While the specific causes of this disease are speculative there are several methods for diagnosis, the most important being the patient's recall of episodes. Most times, those diagnosed with vertiginous seizures are left to self-manage their symptoms or are able to use anti-epileptic medication to dampen the severity of their symptoms. Vertiginous epilepsy has also been referred to as Epileptic vertigo, Vestibular epilepsy, Vestibular seizures, and Vestibulogenic seizures in different cases, but vertiginous epilepsy is the preferred term.