Hallucinations by Oliver Sacks – Extract



Silent Multitudes: Charles Bonnet Syndrome

One day late in November 2006, I got an emergency phone call from a nursing home where I work. One of the residents, Rosalie, a lady in her nineties, had suddenly started seeing things, having odd hallucinations which seemed overwhelmingly real. The nurses had called the psychiatrist in to see her, but they also wondered whether the problem might be something neurological—Alzheimer’s, per­haps, or a stroke.

When I arrived and greeted her, I was surprised to realize that Rosalie was completely blind—the nurses had said noth­ing about this. Though she had not seen anything at all for sev­eral years, she was now “seeing” things, right in front of her.

“What sort of things?” I asked.

“People in Eastern dress!” she exclaimed. “In drapes, walking up and down stairs . . . a man who turns towards me and smiles, but he has huge teeth on one side of his mouth. Animals, too. I see this scene with a white building, and it is snowing—a soft snow, it is swirling. I see this horse (not a pretty horse, a drudgery horse) with a harness, dragging snow away . . . but it keeps switching. . . . I see a lot of chil­dren; they’re walking up and down stairs. They wear bright colors— rose, blue—like Eastern dress.” She had been seeing such scenes for several days.

I observed with Rosalie (as with many other patients) that while she was hallucinating, her eyes were open, and even though she could see nothing, her eyes moved here and there, as if looking at an actual scene. It was that which had first caught the nurses’ attention. Such looking or scanning does not occur with imagined scenes; most people, when visual­izing or concentrating on their internal imagery, tend to close their eyes or else to have an abstracted gaze, looking at noth­ing in particular. As Colin McGinn brings out in his book Mindsight, one does not hope to discover anything surprising or novel in one’s own imagery, whereas hallucinations may be full of surprises. They are often much more detailed than imagery, and ask to be inspected and studied.

Her hallucinations, Rosalie said, were more “like a movie” than a dream; and like a movie, they sometimes fascinated her, sometimes bored her (“all that walking up and down, all that Eastern dress”). They came and went, and seemed to have nothing to do with her. The images were silent, and the peo­ple she saw seemed to take no notice of her. Apart from their uncanny silence, these figures seemed quite solid and real, though sometimes two-dimensional. But she had never before experienced anything like this, so she could not help wonder­ing: was she losing her mind?

I questioned Rosalie carefully but found nothing suggestive of confusion or delusion. Looking into her eyes with an oph­thalmoscope, I could see the devastation of her retinas but noth­ing else amiss. Neurologically, she was completely normal—a strong-minded old lady, very vigorous for her years. I reassured her about her brain and mind; she seemed, indeed, to be quite sane. I explained to her that hallucinations, strangely, are not uncommon in those with blindness or impaired sight, and that these visions are not “psychiatric” but a reaction of the brain to the loss of eyesight. She had a condition called Charles Bon­net syndrome.

Rosalie digested this and said she was puzzled as to why she had started having hallucinations now, after being blind for several years. But she was very pleased and reassured to be told that her hallucinations represented a recognized condi­tion, one that even had a name. She drew herself up and said, “Tell the nurses—I have Charles Bonnet syndrome.” Then she asked, “Who was this Charles Bonnet?”


Charles Bonnet was an eighteenth-century Swiss natural­ist whose investigations ranged broadly, from entomology to reproduction and regeneration in polyps and other animal­cules. When an eye disease made his beloved microscopy impossible, he turned to botany—he did pioneer experiments on photosynthesis—then to psychology, and finally to philoso­phy. When he heard that his grandfather Charles Lullin had started to have “visions” as his eyesight failed, Bonnet asked him to dictate a full account.

John Locke, in his 1690 Essay Concerning Human Under­standing, put forward the notion that the mind is a tabula rasa until it receives information from the senses. This “sen­sationalism,” as it was called, was very popular with the phi­losophes and rationalists of the eighteenth century, including Bonnet. Bonnet also conceived of the brain as “an organ of intricate composition, or rather an assemblage of different organs.” These different “organs” all had their own dedicated functions. (Such a modular view of the brain was radical at the time, for the brain was still widely regarded as undifferenti­ated, uniform in structure and function.) Thus Bonnet attrib­uted his grandfather’s hallucinations to continuing activity in what he postulated were visual parts of the brain—an activ­ity drawing on memory now that it could no longer draw on sensation.

Bonnet—who would later experience similar hallucinations when his own eyesight declined—published a brief account of Lullin’s experiences in his 1760 Essai analytique sur les fa­cultés de l’âme, a book devoted to considering the physiological basis of various senses and mental states, but Lullin’s origi­nal account, which filled eighteen pages of a notebook, was subsequently lost for nearly 150 years, coming to light only at the beginning of the twentieth century. Douwe Draaisma has recently translated Lullin’s account, including it in a detailed history of Charles Bonnet syndrome in his book Disturbances of the Mind.1

Unlike Rosalie, Lullin still had some eyesight left, and his hallucinations were superimposed on what he saw in the real world. Draaisma summarized Lullin’s account:

In February 1758, strange objects had begun to float into his field of vision. It started with something that resembled a blue handkerchief, with a small yellow circle in each corner. . . . The handkerchief followed the movement of his eyes: whether he was looking at a wall, his bed, or a tapestry, the handkerchief blocked out all the ordinary objects in his room. Lullin was perfectly lucid and at no time did he believe that there really was a blue handkerchief floating around. . . .

One day in August two granddaughters came to see him. Lullin was sitting in his armchair opposite the mantelpiece, and his visitors were to his right. From the left, two young men appeared. They were wearing magnificent cloaks, red and grey, and their hats were trimmed with silver. “What handsome gentlemen you’ve brought with you! Why didn’t you tell me they were coming?” But the young ladies swore that they saw no one. Like the handkerchief, the images of the two men dissolved within a few moments. They were followed by many more imaginary visitors in the next few weeks, all of them women; they were beautifully coifed and several of them had a small box on their head. . . .

Somewhat later Lullin was standing at the window when he saw a carriage approaching. It came to a halt at his neighbour’s house and, as he watched in amazement, the carriage grew bigger and bigger until it was level with the eaves of the house some thirty feet from the ground, with everything perfectly in proportion. . . . Lullin was amazed by the variety of images he saw: one time it was a swarm of specks that suddenly turned into a flight of pigeons, another time a group of dancing butterflies. Once he saw a rotating wheel floating in the air, the kind you saw in dockside cranes. On a stroll through the town he stopped to admire an enormous scaffolding, and when he arrived home he saw the same scaffolding standing in the living room, but then in miniature, less than a foot high.

As Lullin found, the hallucinations of CBS would come and go; his lasted for some months and then disappeared for good.


In Rosalie’s case, the hallucinations subsided within a few days, as mysteriously as they had appeared. Almost a year later, though, I got another phone call from the nurses, tell­ing me that she was “in a terrible state.” Rosalie’s first words when she saw me were “All of a sudden, out of a clear blue sky, the Charles Bonnet has come back with a vengeance.” She described how a few days before, “figures started to walk around; the room seemed to crowd up. The walls turned into large gates; hundreds of people started to pour in. The women were dolled up, had beautiful green hats, gold-trimmed furs, but the men were terrifying—big, menacing, disreputable, disheveled, their lips moving as if they were talking.”

In that moment, the visions seemed absolutely real to Rosa­lie. She had all but forgotten that she had Charles Bonnet syn­drome. She told me, “I was so frightened that I screamed and screamed, ‘Get them out of my room, open those gates! Get them out! Then shut the gates!’ ” She heard a nurse say of her, “She is not in her right mind.”

Now, three days later, Rosalie said to me, “I think I know what triggered it again.” She went on to say that she had had a highly stressful, exhausting time earlier in the week—a long, hot journey to see a gastrointestinal specialist on Long Island and a nasty fall backwards on the way. She arrived back many hours later, shocked, dehydrated, in a state of near collapse. She was put to bed and fell into a deep sleep. She awoke the next morning to the terrifying visions of people bursting through the walls of her room, which lasted for thirty-six hours. Then she started to feel somewhat better and recovered her insight into what was happening. At that point, she instructed a young volunteer to track down an account of Charles Bonnet syn­drome on the internet and to give copies of this to the nursing home staff, so that they would know what had been going on.

Over the next few days, her visions grew much fainter and ceased altogether when she was talking with others or lis­tening to music. Her hallucinations had become “shyer,” she said, and now occurred only in the evening, if she sat quietly. I thought of the passage in Remembrance of Things Past where Proust speaks of the church bells of Combray, how their sound seemed muted in the daytime, only to be heard when the hub­bub and blare of the day had died down.


Charles Bonnet syndrome was considered rare before 1990— there were only a handful of case histories in the medical literature.2  I thought this strange, for working in old-age homes and nursing homes for over thirty years, I had seen a number of blind or purblind patients with complex visual hallucinations of the Charles Bonnet type (just as I had seen a number of deaf or nearly deaf patients with auditory—and most often musical—hallucinations). I wondered whether CBS was actually much commoner than the literature seemed to indicate. Recent studies have confirmed that this is the case, although CBS is still little recognized, even by doctors, and there is much to suggest that many or most cases are overlooked or misdiagnosed. Robert Teunisse and his colleagues, studying a population of nearly six hundred elderly patients with visual problems in Holland, found that almost 15 percent of them had complex hallucinations—of people, animals, or scenes—and as many as 80 percent had simple hallucinations—shapes and colors, sometimes patterns, but not formed images or scenes.

Most cases of CBS probably remain at this elementary level of simple patterns or colors. Patients who have simple (and per­haps transient or occasional) hallucinations of this type may not take much notice or remember to report them when they visit a doctor. But some people’s geometrical hallucinations are more persistent. One old lady with macular degeneration, learning of my interest in such matters, described how in the first two years of her visual impairment, she saw

a big blob of light circling around and then vanishing, followed by a colored flag in sharp focus . . . it looked exactly like the British flag. Where it came from, I do not know. . . . For the last few months I have been seeing hexagons, often hexagons in pink. At first there were also tangled lines inside the hexagons, and other little balls of color, yellow, pink, lavender, and blue. Now there are only black hexagons looking for all the world like bathroom tiles.3

While most people with CBS are aware that they are hal­lucinating (often by the very incongruity of their hallucina­tions), some hallucinations may be plausible and in context, as with the “handsome gentlemen” accompanying Lullin’s granddaughters, and these may, at least initially, be taken as real.4

Draaisma’s book provides not only a vivid account of Bonnet’s life and work, but fascinating reconstructions of the lives of a dozen other major figures in neurology whose names are now remembered mostly for the syndromes named after them: Georges Gilles de la Tourette, James Par­kinson, Alois Alzheimer, Joseph Capgras, and others.
Or so it would seem. Recently I came across a marvelous 1845 report by Truman Abell, a physician who started to lose his sight in his fifty-ninth year and had become totally blind by 1842, four years later. He described this in an article for the Boston Medical and Surgical Journal. “In this situation,” he wrote, “I often dreamed of having my sight restored, and of seeing the most beautiful landscapes. At length these landscapes began to appear in miniature when awake: small fields, a few feet square, would appear, clothed with green grass, and other vegetables, some in bloom. These would continue two or three minutes, and then disappear.” The landscapes were followed by an immense variety of other “illusions”—Abell did not use the word “hallucinations”—provided by “an internal sight.” Over the course of several months, his visions increased in complex­ity. His “silent, but impudent visitors” were sometimes intrusive, with three or four people who would sit on his bed or “come to my bed-side, stoop down over me, and look directly into my eyes.” (Often his hallu­cinatory people seemed to acknowledge him, although CBS hallucina­tions typically do not interact with their hallucinators.) One night, he reported, “I was threatened to be run over about 10 o’clock by a drove of oxen; but having my presence of mind, I sat quiet, and with much crowd­ing they all passed without touching me.” Sometimes he saw ranks of thousands of people, splendidly dressed, forming columns that disappeared into the distance. At one point he saw “a column at least half a mile wide” of “men on horseback riding towards the west. . . . They continued to pass for several hours.” “What I have here stated,” Abell wrote at the end of his detailed account, “must appear incredible to those unacquainted with the history of illusive visions. . . . How far my blindness contributed to produce such a result, I am not able to say. Never before have I been able to realize the ancient comparison of the human mind to a microcosm, or universe in miniature . . . [yet] the whole was confined within the organ of mental vision, and occupied, perhaps, a space of less than the tenth part of an inch square.”
A particularly good description of hallucinations in CBS (“I See Purple Flowers Everywhere”) is provided by Lylas and Marja Mogk in their excel­lent book Macular Degeneration, written for patients with this condition.
The reverse may also occur. Robert Teunisse told me how one of his patients, seeing a man hovering outside his nineteenth-floor apartment, assumed this was another one of his hallucinations. When the man waved at him, he did not wave back. The “hallucination” turned out to be his window washer, considerably miffed at not having his friendly wave returned.

Excerpted from Hallucinations by Oliver Sacks. Copyright © 2012 by Oliver Sacks.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Pan Macmillan Australia solely for the personal use of visitors to this web site.


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