Illusory splitting as visual aura symptom in migraine.

Illusory splitting was illustrated as a visual migraine aura symptom in six of 562 Migraine Art pictures. In this type of illusion, objects or persons appear to be split, along fracture lines of varying form and orientation, into two or more parts that may be displaced and separated from each other. The illusion is strongly associated with the presence of elementary geometric hallucinations. Phenomenological similarities and differences of illusory splitting to the visual perceptual disturbances of fragmentation and mosaic illusion are discussed.