She still has some difficulty with reading, especially when she is tired. When she read a book recently, she said,

I lost a word or two in my color spot (I had a black/blind spot after surgery, but it turned into a colored spot a few weeks later, and I still have it. My hallucinations are around that spot.) ... As I type now, after a very long day at work, there is a very faint black-and-white Mickey Mouse from the thirties just off center to the left. He's transparent, so I'm able to see my computer screen as I type. I do, however, make many mistakes typing, as I can't always see the key I need.

But Ellen's blind spot has not prevented her from pursuing graduate courses and even marathon running, as she reported with characteristic good humor:

I ran the New York City marathon in November and tripped on this metal ring, a piece of garbage, on the Verrazano Bridge a little before the second mile. It was on my left side, and I didn't even see it, as I was only looking to my right. I got back up and finished, although I did break a small bone in my hand-which, I think, makes for a wonderful running injury story. In the orthopedics waiting room when I was there, everyone else who had finished the marathon had knee or hamstring injuries.

While Ellen's complex hallucinations started several weeks after her operation, similar "release" hallucinations may appear almost immediately with sudden damage to the occipital cortex. This was the case with Marlene H., a woman in her fifties who came to see me in 1989. She told me that she had awoken one Friday morning in December 1988 with a headache and visual symptoms. She had had migraines for years, and at first she took this as just another visual migraine. But the visual symptoms were different this time: she saw "flashing lights all over ... shimmering lights ... arcs of lightning ... like a Frankenstein thing," and these did not go away in a few minutes, like her usual migraine zigzags, but continued all through the weekend. Then, on Sunday evening, the visual disturbances took on a more complex character. In the upper part of the visual field, to the right, she saw a writhing form "like a Monarch caterpillar, black and yellow, its cilia glistening," along with "incandescent yellow lights, like a Broadway show, going up and down, on and off, nonstop." Though her doctor had rea.s.sured her that this was just "an atypical migraine," things went from bad to worse. On Wednesday, "the bathtub seemed to be crawling with ants ... there were cobwebs covering the walls and ceiling ... people seemed to have lattices on their faces." Two days later she started to experience gross perceptual disturbances: "My husband's legs looked really short, distorted, like someone in a trick mirror. It was funny." But it was less funny, and rather frightening, in the market that afternoon: "Everyone looked ugly, parts of their faces were gone, and eyes-there seemed a blackness in their eyes-everyone looked grotesque." Cars seemed to appear suddenly to the right. Testing her visual fields, waggling her fingers to either side, Marlene found that she could not see them on the right until they crossed the mid-line; she had lost all vision to the right side.

It was only at this point, days after her initial symptoms, that she was finally investigated medically. A CAT scan of her brain revealed a large hemorrhage in the left occipital lobe. There was little to be done therapeutically at this stage; one could only hope that there would be some resolution of her symptoms, some healing or adaptation with time.

After some weeks, the hallucinations and perceptual distortions, which had been largely confined to the right side, did start to die down, but Marlene was left with a variety of visual deficits. She could see, at least to one side, but was bewildered by what she saw: "I would have preferred to be blind," she told me, "instead of not being able to make sense of what I saw.... I had to go slowly, deliberately, to put things together. I would see my sofa, a chair-but I couldn't put it together. It did not add up, at first, to a 'scene.' ... I was a very fast reader before. Now I was slow. The letters looked different."

"When she looks at her watch," her husband interpolated, "at first she can't process it."

Besides these problems of visual agnosia and visual alexia, Marlene was experiencing a sort of runaway visual imagery, outside her control. At one point, she saw a woman wearing a red dress on the street. Then, she said, "I closed my eyes. This woman, almost puppetlike, was moving around, took on a life of her own.... I realize that I had been 'taken over' by the image."

I kept in touch with Marlene at intervals and saw her most recently in 2008, twenty years after her stroke. She no longer had hallucinations, perceptual distortions, or runaway visual imagery. She was still hemianopic, but her remaining vision was good enough for her to travel independently and to work (which involved reading and writing, albeit at her own slow pace).

While Marlene experienced protracted perceptual changes as well as hallucinations after a ma.s.sive occipital lobe hemorrhage, even a "little" occipital lobe stroke can evoke striking, though transient, visual hallucinations. Such was the case with a bright, deeply religious old lady whose hallucinations appeared, "evolved," then disappeared, all within the s.p.a.ce of a few days in July of 2008. I got a call from one of the nurses in a nursing home where I work-we had worked together for many years, and she knew that I was especially interested in visual problems. She asked whether she could bring her great-aunt Dot to see me, and between them, they reconstructed the story. Aunt Dot told me that her vision had seemed "blurry" on July 21, and the following day, "it was like looking through a kaleidoscope ... all this rotating color going through," with sudden "lightning streaks" to the left. She went to her doctor, who, finding that she had a hemianopia to the left, sent her to an emergency room. There it was found that she had atrial fibrillation, and a CAT scan and MRI showed a small area of damage in the right occipital lobe, probably the result of a blood clot dislodged by the fibrillation.

The following day, Aunt Dot saw "octagons with red centers ... moving past me like a film strip, and the moving octagons changed into hexagonal snowflakes." On July 24, she saw "an American flag, outstretched, as if flying."

On July 26, she saw green dots, like little b.a.l.l.s, floating to the left, and these turned into "elongated silvery leaves." When her niece remarked that an early autumn was on the way in Canada and the leaves were already changing color, the hallucinated silvery leaves immediately turned reddish brown. These ushered in a day full of complex visual hallucinations, including "daffodils in bouquets" and "fields of goldenrod." They were followed by a very particular image, which was multiplied. When her niece visited that day, Aunt Dot said, "I'm seeing sailor boys ... one on top of the other, like a film strip." They were colored, but flat and motionless and small, "like stickers." She did not recognize their origin until her niece reminded her that she (the niece) often used a sailor-boy sticker when she sent her aunt a letter-so here, the sailor boy was not a complete invention, but a reproduction of the stickers Aunt Dot had once seen, now multiplied.

The sailor boys were replaced by "fields of mushrooms" and then by a golden Star of David. A neurologist in the hospital had been wearing such a star prominently when he visited her, and she continued to "see" this for hours, though not multiplied like the sailor boys. The Star of David was superseded by "traffic lights, red and green, turning on and off," then by scores of tiny golden Christmas bells. The Christmas bells were replaced by a hallucination of praying hands. Then she saw "gulls, sand, waves, a beach scene," with the gulls flapping their wings. (Up to this point, apparently, there had not been movement within an image; she had seen only static images pa.s.sing in front of her.) The flying gulls were replaced by "a Greek runner wearing a toga ... he looked like an Olympic athlete." His legs were moving, as the gulls' wings had been. The next day she saw stacked and serried coat hangers-this was the last of her complex hallucinations. The day after that, she saw only lightning streaks to the left, as she had seen six days before. And this was the end of what she called her "visual odyssey."

Aunt Dot was not a nurse, like her great-niece, but she had worked for many years as a volunteer in the nursing home. She knew that she had had a small stroke on one side in the visual part of her brain. She realized that the hallucinations were caused by this and were probably transient; she did not fear that she was losing her mind. She did not for a moment think that her hallucinations were "real," although she observed that they were quite unlike her normal visual imagery-much more detailed, more brightly colored, and, for the most part, independent of her thoughts or feelings. She was curious and intrigued, and so she made a careful note of the hallucinations as they occurred and tried to draw them. Both she and her niece wondered why particular images popped up in her hallucinations, to what extent they reflected her life experiences, and how much they might have been prompted by her immediate environment.

She was struck by the sequence of her hallucinations-that they had gone from simple and unformed to more complex, and then back to simple before disappearing. "It's like they moved up the brain, then down again," she said. She was struck by how things she had seen could change into similar forms: octagons turning into snowflakes, blobs into leaves, and perhaps gulls into Olympic athletes. She observed that, in two instances, she had hallucinated something she had seen shortly before: the neurologist's Star of David and the sailor-boy stickers. She noted a tendency to "multiplication"-bunches of daffodils, fields of flowers, octagons galore, snowflakes, leaves, gulls, scores of Christmas bells, and multiple copies of the sailor-boy stickers. She wondered whether the fact that she was a deeply religious Catholic who prayed several times a day had played a part in her seeing a hallucination of praying hands. She was struck by the way in which the silvery leaves she was seeing instantly turned reddish brown when her niece said, "The leaves are changing." She thought the Olympic runner might have been provoked by the fact that the 2008 Olympic Games were coming up, with constant previews on television. I found it impressive and moving that this old lady, curious and intelligent, though not intellectual, would observe her own hallucinations so calmly and thoughtfully and, without being prompted, raise virtually all the questions a neurologist might ask about them.

If one loses half the visual field from a stroke or other injury, one may or may not be aware of the loss. Monroe Cole, a neurologist, became aware of his own field loss only by doing a neurological exam on himself after his coronary bypa.s.s surgery. He was so surprised by his lack of awareness of this deficit that he published a paper about it. "Even intelligent patients," he wrote, "often are surprised when a hemianopia is demonstrated, despite the fact that it has been demonstrated on numerous examinations."

The day after his surgery, Cole began to have hallucinations, in the blind half of his visual field, of people (most of whom he recognized), dogs, and horses. These apparitions did not frighten him; they "moved, danced and swirled, but their purpose was unclear." Often he hallucinated "a pony with his head cradled in my right arm"; he recognized this as his granddaughter's pony, but as with many of his hallucinations, "the colour was wrong." He always realized that these visions were unreal.

In a 1976 paper, the neurologist James Lance provided rich descriptions of thirteen hemianopic patients, and he emphasized that their hallucinations were always recognized as such, if only by their absurdity or irrelevance: giraffes and hippopotamuses sitting on one side of a pillow, visions of s.p.a.cemen or Roman soldiers to one side, and so on. Other physicians have made similar reports; none of their patients ever confuses such hallucinations with reality.

I was therefore surprised and intrigued to receive the following letter from a physician in England, about his eighty-six-year-old father, Gordon H., who had long-standing glaucoma and macular degeneration. He had never had hallucinations before, but recently he had had a small stroke affecting his right occipital lobe. He was "quite sane and largely intellectually undiminished," his son wrote, but

he has not recovered vision and retains a left hemianopia. He has, however, little awareness of his visual loss as his brain appears to fill in the missing parts. Interestingly, though, his visual hallucinations / filling in always seem to be context-sensitive or consistent. In other words, if he is walking in a rural setting, he can be aware of bushes and trees or distant buildings in his left visual field, which when he turns to engage his right side, he discovers are not really there. The hallucinations do, however, seem to be filled in seamlessly with his ordinary vision. If he is at his kitchen bench, he "sees" the entire bench, even to the extent of perceiving a certain bowl or plate within the left side of his vision-but which on turning disappear, because they were never really there. Yet he definitely sees a whole bench, with no clear separation between parts composed of hallucination and true perception.

Gordon H.'s normal visual perception to the right side, one might think, by its normalcy and detail, would immediately show up the relative poverty of the mental construct, the hallucination, on the left. But, his son a.s.serts, he cannot tell one from the other-there is no sense of a boundary; the two halves seem continuous. Mr. H.'s case is unique, to my knowledge.2 He has none of the outlandish, obviously out-of-context hallucinations commonly reported in hemianopia. His hallucinations blend perfectly well with his environment and seem to "complete" his missing perception.

In 1899, Gabriel Anton described a singular syndrome in which patients totally blind from cortical damage (usually from a stroke affecting the occipital lobes on both sides) seemed to be unaware of it. Such patients may be sane and intact in all other ways, but they will insist that they can see perfectly well. They will even behave as if sighted, boldly walking in unfamiliar places. If, in so doing, they collide with a piece of furniture, they will insist that the furniture has been moved, that the room is poorly lit, and so on. A patient with Anton's syndrome, if asked, will describe a stranger in the room by providing a fluent and confident, though entirely incorrect, description. No argument, no evidence, no appeal to reason or common sense is of the slightest use.

It is not clear why Anton's syndrome should produce such erroneous but unshakable beliefs. There are similar irrefutable beliefs in patients who lose the perception of their left side and the left side of s.p.a.ce but maintain that there is nothing missing, even though we can demonstrate convincingly that they live in a hemi-universe. Such syndromes-so-called anosognosias-occur only with damage to the right half of the brain, which seems to be especially concerned with the sense of bodily ident.i.ty.

An even stranger twist was given to the matter in 1984, with the publication of a paper by Barbara E. Swartz and John C. M. Brust. Their patient was an intelligent man who had lost the sight in both eyes from retinal injuries. Normally, he recognized that he was blind and behaved as if blind. But he was also an alcoholic, and twice, while on a drinking binge, he believed that his sight had returned. Swartz and Brust wrote:

During these episodes, he believed he could see; for example, he would walk about without asking for a.s.sistance, or he would watch television, and he claimed he could then discuss the program with friends.... [He] could not read the 20/800 line on a visual acuity chart, or detect a bright light or hand movements in front of his left eye. Nonetheless, he claimed that he could see, and in response to questions he offered plausible confabulations-for example describing the examining room or the appearance of the two physicians with whom he was speaking. In many particulars his descriptions were wrong, but he did not recognize that they were wrong. However, he did admit that he was also seeing things that were not really there. For example, he described the examining room as being full of little children, all wearing similar attire, some of whom were walking in and out of the room through the walls. He also described a dog in the corner eating a bone, and then noted that the walls and the floor of the room were orange. The children, dog and wall colors he recognized as hallucinations, but [he] insisted that his other visual experiences were real.

Returning to Gordon H., I would hazard a guess that damage to the right occipital lobe has produced a unilateral Anton's syndrome (though I do not know if such a syndrome has ever been described). His hallucinations (unlike those of Lance's patients) are informed and shaped by what he perceives in the intact part of his visual field, and mesh seamlessly with his intact perception to the right.

Mr. H. has only to turn his head to discover that he has been deceived, but this does not shake his conviction that he can see equally to both sides. He may, if pressed, accept the term "hallucination," but if he does so he must feel that, for him, hallucination is veridical, that he is hallucinating reality.

1. Before seeing Ellen O., I had never heard of visual perseveration of such duration. Visual perseveration of a few minutes may be a.s.sociated with cerebral tumors of the parietal or temporal lobes or may occur in temporal lobe epilepsy. There are a number of such accounts in the medical literature, including one by Michael Swash, who described two people with temporal lobe epilepsy. One of them had attacks in which "his vision seemed to become fixed, so that an image was retained for several minutes. During these episodes the real world was seen through the retained image, which was clear at first, but then gradually faded."

Similar perseveration may occur with damage or surgery to an eye. My correspondent H.S. was blinded by a chemical explosion at the age of fifteen but had some sight restored by corneal surgery twenty years later. Following the operation, when his surgeon asked if he could now see the surgeon's hand, H.S. replied, "Yes"-but then was astonished to see the hand, or its image, preserving its exact shape and position, for several minutes afterward.

2. In a letter to me, James Lance commented, "I have never encountered hallucination embracing information from the surroundings like Mr. H.'s."

10

Delirious

As a medical student at the Middles.e.x Hospital in London in the 1950s, I saw many patients with delirium, states of fluctuating consciousness sometimes caused by infections with high fevers or by problems like kidney or liver failure, lung disease, or poorly controlled diabetes, all of which may produce drastic changes in blood chemistry. Some patients were delirious from medications, especially those receiving morphine or other opiates for pain. Patients with delirium were almost always on medical or surgical wards, not on neurological or psychiatric wards, for delirium generally indicates a medical problem, a consequence of something affecting the whole body, including the brain, and it disappears as soon as the medical problem has been righted.

It may be that age, even when there is full intellectual function, increases the risk of hallucinations or delirium in response to medical problems and medication-especially with the polypharmacy so often practiced in medicine today. Working in a number of old-age homes, I sometimes see patients on a dozen or more different medications, which are liable to interact with one another in complex ways and, not uncommonly, tip the patients into delirium.1

We had one patient on a medical ward at the Middles.e.x Hospital, Gerald P., who was dying from kidney failure-his kidneys could no longer clear the toxic levels of urea building up in his blood, and he was delirious. Mr. P. had spent much of his life supervising tea plantations in Ceylon. I read this in his chart, but I could have gathered it from what he said in his delirium, for he talked nonstop, with wild a.s.sociational leaps from one thought to another. My professor had said he was "talking nonsense," and at first I could make little sense of what he was saying-but the more I listened, the more I understood. I started spending as much time as I could with him, sometimes two or three hours a day. I began to see how fact and fantasy were admixed in the hieroglyphic form of his delirium, how he was reliving and at times hallucinating the events and pa.s.sions of a long and varied life. It was like being privy to a dream. At first he talked to no one in particular; but once I started to ask him questions, he responded. I think he was glad that someone was listening; he became less agitated, more coherent in his delirium. He died peacefully a few days later.

In 1966, when I started practice as a young neurologist, I began working at Beth Abraham Hospital in the Bronx, a home for those with chronic diseases. One patient there, Michael F., was an intelligent man who, besides other problems, had a very damaged, cirrhotic liver, the result of a severe hepat.i.tis infection. The little liver he had left could not cope with a normal diet, and his protein intake had to be strictly limited. Michael found this hard to take, and every so often he "cheated" by eating some cheese, which he adored. But one day, it seemed, he went too far, for he was found in a near coma. I was called at once, and when I arrived, I found Mr. F. in an extraordinary state, alternating between stupor and delirious agitation. There were brief periods when he would "come together" and show insight into what was going on. "I'm out of this world," he said at one point. "I'm stoned on protein."

When I asked him what this state felt like, he said, "like a dream, confused, sort of crazy, s.p.a.ced out. But I know I'm high, as well." His attention seemed to dart about, touching on one thing and then another almost at random. He was very restless and had all sorts of involuntary movements. I had my own EEG machine at the time, and, wheeling that into Mr. F.'s room, I found that his brain waves were dramatically slowed-his EEG showed cla.s.sic slow "liver waves" as well as other abnormalities. Within twenty-four hours of resuming his low-protein diet, though, Mr. F. was back to normal, as was his EEG.

Many people-especially children-experience delirium with a high fever. One woman, Erika S., recalled this in a letter to me:

I was 11 years old and was home from school with chicken pox and a high fever.... During a fever spike, I experienced a frightening hallucination for what seemed like a very long time, in which my body seemed to shrink and grow.... With each of my breaths, my body would feel like it was swelling and swelling until I was sure that my skin would burst like a balloon. Then when it felt so excruciating, like I had suddenly grown from a normal sized child to a grotesquely fat person ... like a person-balloon ... I would look down at myself, sure that I would see my insides bursting out of my inadequate amount of skin, and blood pouring from enlarged orifices that could not contain my swollen body. But I would "see" my normal sized self ... and looking would reverse the process.... I would feel like my body was shrinking. My arms and legs would get thinner and thinner ... then skinny, then emaciated, then cartoon thin (like the legs on Mickey Mouse in Steamboat Willie) and then so pencil thin that I thought my body would disappear altogether.