Perceptive aspects of visual aura

Abstract

Visual aura is the most common feature associated with migraine, though it can occur separately. In both cases it often represents a dramatic event, especially for patients who experience it for the first time. Besides, its subjective characteristics may illuminate on the functional architecture of the visual cortex. Repetitive events of migraine and visual aura have been suggested to affect the visual system in the long run, both on the cortical and precortical level. In effect, objective investigation of visual functions in patients support the idea that a selective damage does occur, so that more attention to visual examination seems to be justified. In this paper, subjective and psychophysical aspects of visual aura are examined, lastly highlighting and discussing the interesting correlations found between this condition and normal-tension glaucoma.

The Visual System in Migraine: From the Bench Side to the Office

“…The nature of the Greek word for aura (“breeze”) must be remembered while clinically interviewing a patient presenting symptoms of MA: any “migraineur” reporting abrupt‐onset visual or non‐visual migraine auras must have their diagnosis challenged, since migraine auras usually display a steady progressive presentation . The striking variety of visual symptoms of aura was well described by several authors, and the interested reader ought to take a look after the recent papers of Queiroz et al and Aleci and Liboni . The most puzzling cases are those of familial and sporadic hemiplegic migraine, prolonged migraine aura without infarction, migraine with unilateral motor symptoms (MUMS), and migraine‐related persistent visual phenomena .…”

“…7,20 The striking variety of visual symptoms of aura was well described by several authors, and the interested reader ought to take a look after the recent papers of Queiroz et al 47,48 and Aleci and Liboni. 49 The most puzzling cases are those of familial and sporadic hemiplegic migraine, 20 prolonged migraine aura without infarction, 20 migraine with unilateral motor symptoms (MUMS), 50 and migraine-related persistent visual phenomena. 51 Despite the great similarity, some of these syndromes combine or have isolated either positive (somatosensory, visual, auditory, vestibular) or negative (visual, somatosensory, and/or motor) phenomena.…”

Hallucinations Associated with Neurological Disorders and Sensory Loss

“…Headache is its most characteristic feature but other symptoms may occur, such as aura, which, according to the International Headache Society, is "a recurrent disorder consisting in episodes of reversible focal neurological symptoms that usually resolve gradually after 5-20 min and last less than 1h" (Aleci and Liboni 2009 ) . Visual aura is the most frequent form of migraine aura, followed by sensory, aphasic and motor aura (Russel and Olesen 1996 ) .…”

“…The neural basis for the migraine aura is thought to be cortical spreading depression, a phenomenon fi rst described by Leão in rodents and consisting in a wave of neuronal and glial depolarization, followed by long-lasting suppression of neural activity (Tfelt-Hansen 2010 ) . The metabolic wavefront would sequentially trigger the cortical receptive fi eld cells tuned to orientation discrimination, thus leading to the hallucinatory perception of segments with speci fi c orientations forming the typical zigzag pattern (Aleci and Liboni 2009 ) . fMRI studies have identi fi ed propagated waves of blood fl ow and brain activity during migraine visual aura, with temporal and spatial characteristics remarkably similar to those seen in cortical spreading depression, including transient hyperperfusion followed by sustained hypoperfusion (Hadjikhani et al 2001 ) .…”

<p>The Psychophysical Assessment of Hierarchical Magno-, Parvo- and Konio-Cellular Visual Stream Dysregulations in Migraineurs</p>

“…Neuroimaging and behavioral detection and discrimination techniques using various spatiotemporal patterns, colors, forms, or tasks involving word recognition, word priming, or spatial orienting attention have also pointed to visual extrastriate cortical activity in both aura and nonaura migraineurs,11–17 while V1 processing has been implicated with neuroimaging or with psychophysical threshold measurements of spatiotemporal contrast or texture orientation 17–25. Meanwhile, automated perimetry, temporal flicker, electrooculography and evoked potential measurements have pointed either to subcortical pre-striatal deficits,26–30 or to more peripheral, retina photoreceptor dysregulation31 or ocular damage based on ischemia and vasospasmic nerve damage similar to that observed in glaucoma 32–35…”