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Scintillating scotoma

(Redirected from Fortification spectra)

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), also known as visual migraine or migraine aura.[4] It is often confused with retinal migraine, which originates in the eyeball or socket.

Scintillating scotoma
Other namesVisual migraine[1]
Teichopsia[2]
Example of a scintillating scotoma, as may be caused by cortical spreading depression
SpecialtyNeurology, Neuro-ophthalmology
SymptomsAura in vision, nausea, dizziness, brain fog
ComplicationsMigraine onset
DurationLess than 60 minutes[3]
CausesCortical spreading depression
Risk factorsMigraine sufferer
Differential diagnosisPersistent aura without infarction, Retinal migraine
PreventionAvoiding migraine triggers
PrognosisSelf-limiting
Artist's depiction of a Scintillating scotoma, exhibiting a flashing visual pattern similar to Dazzle camouflage used during WWI.
Artist's depiction of a scintillating scotoma, exhibiting a flashing visual pattern similar to dazzle camouflage used during WWI.

Signs and symptoms

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An artist's depiction of a scintillating scotoma with a bilateral arc

Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye.[5][6] The affected area flickers but is not dark. It then gradually expands outward from the initial spot. Vision remains normal beyond the borders of the expanding scotoma(s), with objects melting into the scotoma area background similarly to the physiological blind spot, which means that objects may be seen better by not looking directly at them in the early stages when the spot is in or near the center. The scotoma area may expand to occupy one half of the visual area of one eye, or it may be bilateral. It may occur as an isolated symptom without headache in acephalgic migraine.[7]

 
In teichopsia, migraine sufferers see patterns in the shape of the walls of a star fort.

As the scotoma area expands, some people perceive only a bright flickering area that obstructs normal vision, while others describe seeing various patterns. Some describe seeing one or more shimmering arcs of white or colored flashing lights. An arc of light may gradually enlarge, become more obvious, and may take the form of a definite zigzag pattern, sometimes called a fortification spectrum (i.e. teichopsia, from Greek τεῖχος, town wall), because of its resemblance to the fortifications of a castle or fort seen from above.[3] It also can resemble the dazzle camouflage patterns used on ships in World War I. Others describe patterns within the arc as resembling herringbone or Widmanstätten patterns.

The visual anomaly results from abnormal functioning of portions of the occipital cortex at the back of the brain, not in the eyes nor any component thereof, such as the retinas.[3] This is a different disease from retinal migraine, which is monocular (only one eye).[8]

It may be difficult to read and dangerous to drive a vehicle while the scotoma is present. Normal central vision may return several minutes before the scotoma disappears from peripheral vision.

Sufferers can keep a diary of dates on which the episodes occur to show to their physician, plus a small sketch of the anomaly, which may vary between episodes.

Animated depictions

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    Flickering animation of a scintillating scotoma, where the scintillations were of a zigzag pattern starting in the center of vision, surrounded by a somewhat larger scotoma area with distortion of shapes but otherwise melting into the background similarly to the physiological blind spot
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    A depiction of a scintillating scotoma that was almost spiral-shaped, with distortion of shapes but otherwise melting into the background similarly to the physiological blind spot. This depiction shows the type of patterning that some have described as similar to Widmanstätten patterns.
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    A depiction of a scintillating scotoma that was almost spiral-shaped, with distortion of shapes but otherwise melting into the background similarly to the physiological blind spot

Causes

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Scintillating scotomas are most commonly caused by cortical spreading depression, a pattern of changes in the behavior of nerves in the brain during a migraine. Migraines, in turn, may be caused by genetic influences and hormones. People with migraines often self-report triggers for migraines involving stress or foods,[9] or bright lights.[10] While monosodium glutamate (MSG) is frequently reported as a dietary trigger,[11] other scientific studies do not support this claim.[12]

The Framingham Heart Study, published in 1998, surveyed 5,070 people between ages 30 and 62 and found that scintillating scotomas without other symptoms occurred in 1.23% of the group. The study did not find a link between late-life onset scintillating scotoma and stroke.[13]

Prognosis

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Symptoms typically appear gradually over 5 to 20 minutes and generally last less than 60 minutes, leading to the headache in classic migraine with aura, or resolving without consequence in acephalgic migraine.[3] For many sufferers, scintillating scotoma is first experienced as a prodrome to migraine, then without migraine later in life. Typically the scotoma resolves spontaneously within the stated time frame, leaving no subsequent symptoms, though some report fatigue, nausea, and dizziness as sequelae.[14]

Names and etymology

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The British physician John Fothergill described the condition in the 18th century and called it fortification spectrum.[15] The British physician Hubert Airy coined the term scintillating scotoma for it by 1870; he derived it from the Latin scintilla "spark" and the Ancient Greek skotos "darkness".[16] Other terms for the condition include flittering scotoma, fortification figure, fortification of Vauban, geometrical spectrum, herringbone, Norman arch, teichopsia,[17] and teleopsia.[18]

See also

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References

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  1. ^ Prasad, Sashank. "Visual Migraine" (PDF). Brigham and Women's Hospital. Harvard Medical School. Archived from the original (PDF) on 18 March 2015. Retrieved 4 October 2016.
  2. ^ Martin, Elizabeth A, ed. (2010). "teichopsia". Concise Medical Dictionary. doi:10.1093/acref/9780199557141.001.0001. ISBN 978-0-19-955714-1.
  3. ^ a b c d Troost, B. Todd (2004). Glaser, Joel S. (ed.). "Neuro-Ophthalmology (4th edition): Genetics in Migraine". Archived from the original on 19 July 2009. Retrieved 24 June 2015.
  4. ^ Lee, Ann (11 July 2022). "'It starts as a line of light, then works its way across my vision': the disorienting mystery of migraine auras". The Guardian.
  5. ^ "Scintillating Scotoma: The Strange World of Migraine Auras". MigraineAgain.com. Retrieved 2023-11-07.
  6. ^ Silberstein, Stephen D. (2003). "Migraine with Aura". Encyclopedia of the Neurological Sciences. pp. 174–179. doi:10.1016/B0-12-226870-9/00194-5. ISBN 978-0-12-226870-0.
  7. ^ Maggioni, Ferdinando; Toldo, Giulia; Terrin, Alberto; Mainardi, Federico (January 2019). "Simultaneous bilateral visual auras: A case report". Cephalalgia. 39 (1): 162–163. doi:10.1177/0333102418761046. PMID 29463134.
  8. ^ Grosberg, Brian M.; Solomon, Seymour; Lipton, Richard B. (August 2005). "Retinal migraine". Current Pain and Headache Reports. 9 (4): 268–271. doi:10.1007/s11916-005-0035-2. PMID 16004843.
  9. ^ Scott, Paul M. "Scintillating Scotoma (Migraine Scotoma)". Retrieved 22 June 2020. Alternate version: "Scintillating Scotoma (Migraine Scotoma)". Archived from the original on 20 October 2012.
  10. ^ Newman, Lawrence C. (19 July 2017). "Loud Noises, Bright Lights, and Migraines". WebMD. Retrieved 22 June 2020.
  11. ^ Sun-Edelstein C, Mauskop A (June 2009). "Foods and supplements in the management of migraine headaches". The Clinical Journal of Pain. 25 (5): 446–52. doi:10.1097/AJP.0b013e31819a6f65. PMID 19454881.
  12. ^ Freeman M (October 2006). "Reconsidering the effects of monosodium glutamate: a literature review". Journal of the American Academy of Nurse Practitioners. 18 (10): 482–6. doi:10.1111/j.1745-7599.2006.00160.x. PMID 16999713.
  13. ^ Christine A. C. Wijman; Philip A. Wolf; Carlos S. Kase; Margaret Kelly-Hayes; Alexa S. Beiser (August 1998). "Migrainous Visual Accompaniments Are Not Rare in Late Life: the Framingham Study". Stroke. 29 (8): 1539–1543. doi:10.1161/01.STR.29.8.1539. PMID 9707189.
  14. ^ Ekbom, Karl (July 1974). "Migraine in Patients with Cluster Headache". Headache: The Journal of Head and Face Pain. 14 (2): 69–72. doi:10.1111/j.1526-4610.1974.hed1402069.x. PMID 4853218.
  15. ^ Blom 2010, p. 199.
  16. ^ Blom 2010, p. 464.
  17. ^ Blom 2010, pp. 463–464.
  18. ^ Blom 2009, p. 199.

Works cited

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Further reading

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