Therefore, there is still discussion about whether these symptoms are part of the aura spectrum. Furthermore, these symptoms have not been prospectively studied in migraine without aura patients. However, information on gradual expansion was not collected. In the diary study, this was registered in 33% of aurasĥ. Additionally, patients often report that during migraine auras their vision is “blurred” or “foggy” or that they see “heat waves”. This suggests that more complex processes of visual perception, involving orientation and size, can also be altered during migraine attacks. Sometimes patients report complex visual phenomena during their auras, such as distortions of observed body parts (for example, disproportionately large ears, sometimes referred to as the Alice in Wonderland syndrome) or visual splitting (one half of the observed face shifts upwards or downwards)ġ3. However, a prospective diary study showed that in 34% of patients the aura symptoms start simultaneously, suggesting that CSD may also start in a non-symptomatic brain area and reach two cortical areas at about the same timeġ1. It is believed that in these cases the CSD expands from the occipital cortex to the motor cortexġ0. Patients can report a classic cascade in aura symptoms: the aura starts with visual symptoms and is followed by sensory symptoms, aphasia, and sometimes motor problemsĩ. Preclinical and clinical studies suggest that the velocity of CSD through the occipital cortex is in line with the velocity of the visual spread observed by patientsĨ. This corresponds with the suspected underlying pathophysiological mechanism called “cortical spreading depolarization” (CSD): a wave of intense neuronal and glial depolarization that is followed by neuronal depression. Gradual expansion is considered the most typical feature of a migraine auraġ. This picture illustrates the typical gradual expansion of a migraine aura along with the characteristic fortification spectrum. In a general-population study, median attack frequency was 12 attacks per year and 25% of patients with migraine had at least two attacks per month Migraine with aura patients can still have attacks without aura. If a person has only attacks without aura, he or she is classified as migraine-without-aura. If a person has had two attacks fulfilling criteria for migraine with aura, he or she is classified as a migraine with aura patientġ. Besides having visual symptoms, patients may experience sensory symptoms, speech problems, and sometimes motor symptoms during their aurasġ. When patients close their eyes, the positive features of an aura remain visible. Furthermore, positive symptoms do not have to occur patients can also report that the scotoma (that is, the blind spot or the hole in the visual field) has no colors or jagged lines. Patients commonly report that the aura starts with light flashes or balls of light that gradually expand across the visual fieldĥ. The positive symptoms often take shapes other than a classic fortification spectrum. These visual symptoms are fully reversible and should not be accounted for by another disorder, according to the third edition of the International Classification of Headache Disordersġ. The expansion is gradual and lasts between 5 and 60 minutesġ. In its most typical form, a visual aura begins with a “scintillating scotoma”, a small blind spot with a flickering, brightly colored, and typically jagged front-the so-called fortification spectrum-that generally expands in a C-shape to one side of the visual field (ģ.
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