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An aura is a perceptual disturbance experienced by some with migraines or seizures before either the headache or seizure begins. 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 epileptic people 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 not uncommon 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.〔(Sudden Onset Panic: Epileptic Aura or Panic Disorder? ) Robin A. Hurley, M.D., Ronald Fisher, M.D., Ph.D. and Katherine H. Taber, Ph.D.〕 ==Seizures== An epileptic aura is the consequence of the activation of functional cortex by abnormal, unilateral, and brief neuronal discharge.〔Fernandez-Torre, JL. (2002). Epileptic auras: classification, pathophysiology, practical usefulness, differential diagnosis and controversials. Revista de Neurologia, 34(10): 977-983.〕 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.〔Sharma, S., Dixit, V. (2013). Epilepsy – A Comprehensive Review. International Journal of Pharmacological Research & Review, 2(12):61-80.〕 The activation in the brain during an aura can spread through multiple regions continuously or discontinuously, on the same side or to both sides.〔Tuxhorn, I. E. B. (2005). Somatosensory auras in focal epilepsy: A clinical, video EEG and MRI study. Seizure: European Journal of Epilepsy, 14(4):262-268.〕 Auras are particularly common in focal seizures. If the motor cortex is involved in the over excitation 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.〔Foldvary-Schaefer, N. & Unnwonqse, K. (2011). Localizing and Lateralizing features of auras and seizures. Epilepsy behavior 20: 160-166〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Aura (symptom)」の詳細全文を読む スポンサード リンク
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