An aura is a perceptual disturbance experienced by some with

epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...

migraine Migraine (, ) is a common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few hou ...

. An epileptic aura is a

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...

. Epileptic and migraine auras are due to the involvement of specific areas of the brain, which are those that determine the symptoms of the aura. Therefore, if the visual area is affected, the aura will consist of visual symptoms, while if a sensory one, then sensory symptoms will occur. Epileptic auras are subjective sensory or psychic phenomena due to a

focal seizure Focal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parie ...

, i.e. a seizure that originates from that area of the brain responsible for the function which then expresses itself with the symptoms of the aura. It is important because it makes it clear where the alteration causing the seizure is located. An epileptic aura is in most cases followed by other manifestations of a seizure, for example a

convulsion A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is sometimes used as a s ...

, since the epileptic discharge spreads to other parts of the brain. Rarely it remains isolated. Auras, when they occur, allow some people who have epilepsy time to prevent injury to themselves and/or others when they lose consciousness.

Migraine

The aura of migraine is visual in the vast majority of cases, because dysfunction starts from the visual cortex. The aura is usually followed, after a time varying from minutes to an hour, by the migraine headache. However, the migraine aura can manifest itself in isolation, that is, without being followed by headache. The aura can stay for the duration of the migraine; depending on the type of aura, it can leave the person disoriented and confused. It is common for people with migraines 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 attack Panic attacks are sudden periods of intense fear and discomfort that may include palpitations, sweating, chest pain or chest discomfort, shortness of breath, trembling, dizziness, numbness, confusion, or a feeling of impending doom or of losing ...

s or

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

attacks, which creates difficulties in diagnosis. The

differential diagnosis In healthcare, a differential diagnosis (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that p ...

of patients who experience symptoms of

paresthesia Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...

derealization Derealization is an alteration in the perception of the external world, causing those with the condition to perceive it as unreal, distant, distorted or falsified. Other symptoms include feeling as if one's environment is lacking in spontaneity, ...

, dizziness, chest pain, tremors, and palpitations can be quite challenging.

Seizures

An epileptic aura is the consequence of the activation of functional cortex by abnormal neuronal discharge. In addition to being a warning sign for an impending seizure, the nature of an aura can give insight into the localization and lateralization of the

. 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 Focal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parie ...

. If the

motor cortex The motor cortex is the region of the cerebral cortex believed to be involved in the planning, control, and execution of voluntary movements. The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately a ...

is involved in the overstimulation of neurons, motor auras can result. Likewise, somatosensory auras (such as tingling, numbness, and pain) can result if the somatosensory cortex is involved. When the

primary somatosensory cortex In neuroanatomy, the primary somatosensory cortex is located in the postcentral gyrus of the brain's parietal lobe, and is part of the somatosensory system. It was initially defined from surface stimulation studies of Wilder Penfield, and paralle ...

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 The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...

. 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 The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to ...

and complex symptoms from the temporo-occipital cortex at the location of the auditory association areas.

Examples

Migraine-aura-aka-scintillating-scotoma-anecdoteal-depiction

An aura sensation can include one or a combination of the following:

Visual changes

* Bright lights and blobs * Zigzag lines * Distortions in the size or shape of objects * Vibrating

visual field The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point ...

Scintillating scotoma Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache, but can also occur acephalgically (without headache), al ...

** Shimmering, pulsating patches, often curved **

Tunnel vision Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision. Causes Tunnel vision can be caused by: Eyeglass users Eyeglass users experience tunnel vision t ...

Scotoma A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mam ...

** Blind or dark spots ** Curtain like effect over one eye ** Slowly spreading spots *

Kaleidoscope A kaleidoscope () is an optical instrument with two or more reflecting surfaces (or mirrors) tilted to each other at an angle, so that one or more (parts of) objects on one end of these mirrors are shown as a regular symmetrical pattern when v ...

effects * Temporary blindness in one or both eyes * Heightened sensitivity to light

Auditory changes

* Hearing voices or sounds that do not exist:

auditory hallucinations An auditory hallucination, or paracusia, is a form of hallucination that involves perceiving sounds without auditory stimulus. While experiencing an auditory hallucination, the affected person would hear a sound or sounds which did not come from t ...

* Modification of voices or sounds in the environment: buzzing,

tremolo In music, ''tremolo'' (), or ''tremolando'' (), is a trembling effect. There are two types of tremolo. The first is a rapid reiteration: * Of a single Musical note, note, particularly used on String instrument#Bowing, bowed string instrument ...

amplitude modulation Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...

or other modulations * Heightened sensitivity to hearing *

Vestibular The Vestibular (from pt, vestíbulo, "entrance hall") is a competitive examination and is the primary and widespread entrance system used by Brazilian universities to select the students admitted. The Vestibular usually takes place from Novem ...

dysfunction causing

vertigo Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties w ...

Other sensations

* Strange smells (

phantosmia Phantosmia (phantom smell), also called an olfactory hallucination or a phantom odor, is smelling an odor that is not actually there. It can occur in one nostril or both. Unpleasant phantosmia, cacosmia, is more common and is often described as s ...

) or tastes (

gustatory hallucination A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...

s) * Heightened sensitivity to smell *

Synesthesia Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who re ...

* ''

Déjà vu ''Déjà vu'' ( , ; "already seen") is a French loanword for the phenomenon of feeling as though one has lived through the present situation before.Schnider, Armin. (2008). ''The Confabulating Mind: How the Brain Creates Reality''. Oxford Univer ...

'' or ''

jamais vu In psychology, ''jamais vu'' ( , , ), a French loanword meaning "never seen", is the phenomenon of experiencing a situation that one recognizes in some fashion, but that nonetheless seems novel and unfamiliar. Overview Jamais vu is often desc ...

'' * Cephalic aura, a perception of movement of the head or inside the head * Abdominal aura, such as an

epigastric In anatomy, the epigastrium (or epigastric region) is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane. Pain may be referred to the epigastrium from damage to structures derived from the f ...

rising sensation *

Nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

* A sudden feeling of anxiety, fear, or foreboding * Numbness or tingling (

) * Weakness on one side of the body (

hemiparesis Hemiparesis, or unilateral paresis, is weakness of one entire side of the body (''wikt:hemi-#Prefix, hemi-'' means "half"). Hemiplegia is, in its most severe form, complete paralysis of half of the body. Hemiparesis and hemiplegia can be caused ...

) * Feelings of being separated from or floating above one's body (

dissociation Dissociation, in the wide sense of the word, is an act of disuniting or separating a complex object into parts. Dissociation may also refer to: * Dissociation (chemistry), general process in which molecules or ionic compounds (complexes, or salts ...

) * Sensation of limbs or teeth growing * Feeling of overheating and sudden perspiration * Inability to speak (

aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in th ...

) or slurred speech

References

External links

{{DEFAULTSORT:Aura (Symptom) Medical terminology Symptoms and signs of mental disorders Hallucinations Epilepsy Migraine