Oliver Sacks - Hallucinations

For most people with classical migraine, the scintillating scotoma is the chief visual effect, and things go no further. But sometimes, within the scotoma, there are other patterns. In my own migraine auras, I would sometimes see — vividly with closed eyes, more faintly and transparently if I kept my eyes open — tiny branching lines like twigs or geometrical structures: lattices, checkerboards, cobwebs, and honeycombs. Unlike the scintillating scotoma itself, which had a fixed appearance and a slow, steady rate of progression, these patterns were in continual motion, forming and re-forming, sometimes assembling themselves into more complicated forms like Turkish carpets or complex mosaics or three-dimensional shapes like tiny pinecones or sea urchins. Usually these patterns stayed inside the scotoma, to one side or the other of my visual field, but sometimes they seemed to break loose and scatter themselves all over.

One has to call these hallucinations, even though they are only patterns and not images, for there is nothing in the external world that corresponds to the zigzags and checkerboards — they are generated by the brain. And there may also be startling perceptual changes with migraine. I might sometimes lose the sense of color or of depth (for other people, color or depth may intensify). Losing the sense of movement was especially startling, for instead of continuous movement, I would see only a stuttering series of “stills.” Objects might change size or shape or distance, or get misplaced in the visual field so that, for a minute or two, the whole visual world would be unintelligible.

There are many variations on the visual experiences of migraine. Jesse R. wrote to me that during a migraine, “I think my mind loses its ability to read shapes and misinterprets them.… I think I see a person instead of the coat rack … or I often think I see movement across a table or floor. What is strange is that the mind always errs toward giving life to inanimate objects.”

Toni P. wrote that before her migraines, she might see alternating black and white zigzag lines in her peripheral vision: “shiny geometric shapes, flashes of light. Sometimes it is as if whatever I am viewing is through a sheer curtain that is blowing in the wind.” But sometimes, for her, a scotoma is simply a blank spot, producing an uncanny sense of nothingness:

I was studying for a major lab exam when all of a sudden I knew something was missing — the book was in front of me; I could see the edges, but there were no words, no graphs, no diagrams. It wasn’t as if there was a blank page, it just didn’t exist. I only knew it SHOULD be there by reason. That was the strangeness of it.… It lasted for about twenty minutes.

Another woman, Deborah D., had an attack of migraine in which, she wrote:

When I looked at the computer screen, I could not read anything; the screen was a crazy blur … of multiple images.… I could not see the numbers on the phone’s keypad, it was as if I was seeing through a fly’s lens, multiple images, not double, not triple, but many, many images of wherever I looked.

It is not only the visual world that may be affected in a migraine aura. There may be hallucinations of body image — the feeling that one is taller or shorter, that one limb has shrunk or grown gigantic, that one’s body is tilted at an angle, and so forth.

It is known that Lewis Carroll had classical migraines, and it has been suggested (by Caro W. Lippman and others) that his migraine experiences may have inspired Alice in Wonderland’s strange alterations of size and shape. Siri Hustvedt, in a New York Times blog, described her own transcendent Alice-in-Wonderland syndrome:

As a child I had what I called “lifting feelings.” Every once in a while I had a powerful internal sensation of being pulled upward, as if my head were rising, even though I knew my feet hadn’t left the ground. This lift was accompanied by what can only be called awe — a feeling of transcendence. I variously interpreted these elevations as divine (God was calling) or as an amazed connection to things in the world. Everything appeared strange and wondrous.

There may be auditory misperceptions and hallucinations in migraine: sounds are amplified, reverberant, distorted; occasionally voices or music are heard. Time itself may seem distorted.

Hallucinations of smell are not uncommon — the smells are often intense, unpleasant, strangely familiar, yet unspecifiable. I myself twice hallucinated a smell before a migraine, but a pleasant one — the smell of buttered toast. The first time it happened, I was at the hospital and went in search of the toast — it did not occur to me that I was having a hallucination until the visual fortifications started up, a few minutes later. On both occasions there was a memory or pseudomemory of being a little boy in a high chair about to have buttered toast at teatime. One migraineur wrote to me, “I have always smelled beef roasting about thirty minutes before the onset of a migraine.” 39 39 This woman, Ingrid K., also reported that she sometimes has “another strange experience just before the migraine … I think I recognize everyone I see. I don’t know who they are … but everyone looks familiar.” Other correspondents have described a similar “hyperfamiliarity” at the start of migraine — and this feeling is occasionally part of an epileptic aura, as Orrin Devinsky and his colleagues have described. A patient described by G. N. Fuller and R. J. Guiloff had “vivid olfactory hallucinations, lasting five minutes, of either her grandfather’s cigars or peanut butter.”

When I worked in a migraine clinic as a young neurologist, I made a point of asking every patient about such experiences. They were usually relieved that I asked, for people are afraid to mention hallucinations, fearing that they will be seen as psychotic. Many of my patients habitually saw patterns in their migraine auras, and a few had a host of other strange visual phenomena, including distortion of faces or objects melting or flickering into one another; multiplication of objects or figures; or persistence or recurrence of visual images.

Most migraine auras remain at the level of elementary hallucinations: phosphenes, fortifications, and geometrical figures of other sorts — but more complex hallucinations, though rare in migraine, do occur. My colleague Mark Green, a neurologist, described to me how one of his patients had the same vision in every migraine attack: a hallucination of a worker emerging from a manhole in the street, wearing a white hard hat with an American flag painted on it.

S. A. Kinnier Wilson, in his encyclopedic Neurology , described how a friend of his would always have a stereotyped hallucination as part of a migraine aura:

[He] used at first to see a large room with three tall arched windows and a figure clad in white (its back toward him) seated or standing at a long bare table; for years this was the unvarying aura, but it was gradually replaced by a cruder form (circles and spirals), which, later still, developed once in a while without subsequent headache.

Klaus Podoll and Derek Robinson, in their beautifully illustrated monograph Migraine Art , have collected many reports of complex hallucinations in migraine from the world literature. People may see human figures, animals, faces, objects, or landscapes — often multiplied. One man reported seeing “a fly’s eye made of millions of light-blue Mickey Mouses” during a migraine attack, but this hallucination was confined to the temporarily blind half of his visual field. Another saw a “crowd of [more than] one hundred people, some dressed in white.”

There may also be lexical hallucinations. Podoll and Robinson cite a case from the nineteenth-century literature: