A seizure aura is a subjective experience felt by some individuals moments before a larger seizure event begins. It acts as a warning sign. These sensations are highly personal and vary significantly, though for any single individual, the aura often presents the same way each time. Understanding these feelings is important because they offer a glimpse into the initial stages of a seizure, allowing a person to take protective action.
Defining the Seizure Aura
A seizure aura is technically a focal onset aware seizure. This means the event is caused by abnormal electrical activity starting in a specific, limited area on one side of the brain. The person remains fully conscious and aware because the activity has not yet spread to regions that cause loss of awareness. This retained awareness allows the experience to be perceived as an unusual sensation, serving as the warning.
The aura is the first manifestation of the seizure, sometimes called the pre-ictal stage. It can last from a few seconds up to a minute or two before it either stops or progresses into a more extensive seizure event. The specific feeling of the aura directly reflects the part of the brain where the electrical disturbance originates. For example, an aura starting in the occipital lobe, the brain’s visual processing center, will involve visual changes.
Sensory and Perceptual Manifestations
Auras frequently involve changes to the five senses, manifesting as perceptions of things not actually present. Visual disturbances are common, often originating from the occipital lobe. These can include seeing simple, unformed images like flashing lights, zigzag lines, or colored spots moving across the visual field.
Some people experience complex visual changes where objects appear distorted in size or shape, known as metamorphopsia. This includes micropsia, where objects seem abnormally small, or macropsia, where they appear unusually large. Auditory auras, arising from the temporal lobe, are often reported as hearing simple sounds like ringing, buzzing, or hissing noises.
Unusual smells (olfactory hallucinations) and tastes (gustatory hallucinations) are also recognized auras, usually linked to temporal lobe activity. Phantom smells are frequently reported as unpleasant, such as burnt rubber, metallic, or foul odors. Tastes are often described as metallic, sour, or bitter, despite the person having nothing in their mouth.
A tactile, or somatosensory, aura involves strange skin sensations originating in the parietal lobe. These auras are commonly felt as paresthesia, which is a sensation of tingling, numbness, or an “electric shock” feeling on one side of the body. Sometimes, a person reports a strange feeling of something crawling on their skin.
Emotional and Visceral Experiences
Many auras involve profound internal experiences related to emotion, memory, and internal body states. Sudden, intense emotional shifts are common, often presenting as an overwhelming feeling of fear, anxiety, or impending doom. Less frequently, a person may experience a sudden surge of pleasure, joy, or intense well-being.
Brain areas that process memory can be affected, leading to cognitive auras that alter a person’s sense of reality. A recognized example is déjà vu, the intense feeling that the current moment has been experienced before. Conversely, some individuals experience jamais vu, where a familiar situation suddenly feels completely new or unfamiliar.
Visceral auras involve sensations related to the internal organs, most often the stomach. The “epigastric rising sensation” is a common aura, described as a churning or wave-like feeling of discomfort or nausea that rises toward the chest or throat. Other internal feelings can include sudden lightheadedness, dizziness, or abrupt changes in heart rate.
The Importance of Describing Auras
The detailed description of an aura is highly valuable to medical professionals because it functions as a neurological map, pointing toward the seizure’s origin. Since the specific feeling correlates with the area of the brain where the electrical activity begins, a detailed account helps localize the epileptogenic zone. For instance, an olfactory aura is associated with the temporal lobe, while a visual aura is linked to the occipital lobe.
Accurately communicating these subjective feelings to a doctor is a foundational step in diagnosis and treatment planning. This information, combined with results from an electroencephalogram (EEG) and brain imaging, guides the healthcare team in determining the specific type of epilepsy. For individuals considering surgery, the aura’s characteristics are important for pinpointing the exact brain area to target.