Hallucinations

3. 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.

4. 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.

5. I have heard from at least a dozen people who, like Arthur and Marjorie, hallucinate musical notation; some of them have eye problems, some parkinsonism, some see music when they have a fever or delirium, some see it hypnopompically when they awaken. All but one are amateur musicians who often spend many hours a day studying scores. This very specialized and repetitive sort of visual study is peculiar to musicians. One may read books for hours a day, but one does not usually study print itself in such an intensive way (unless one is a type designer or proofreader, perhaps).

A page of music is far more complex visually than a page of print. With musical notation, one has not just the notes themselves but a very dense set of information contained in symbols for key signatures, clefs, turns, mordents, accents, rests, holds, trills, etc. It seems likely that intensive study and practice of this complex code somehow imprints it in the brain, and should any tendency to hallucination later develop, these “neural imprints” may predispose to hallucinations of musical notation.

And yet people with no particular training or even interest in music may also have hallucinations of musical notation, as Dominic ffytche has pointed out. In a letter to me, he wrote, “although prolonged exposure to music increases the likelihood of musical eyes, it is not a prerequisite.”

6. I was reminded, when she said this, of a case I had heard of in which as a patient ate cherries from a bowl, they were replaced by hallucinatory cherries, a seemingly endless cornucopia of cherries, until, suddenly, the bowl was totally empty. And of another case, of a man with CBS who was picking blackberries. He picked every one he could see; then, to his delight, he saw four more he had missed — but these turned out to be hallucinations.

7. Something about visual movement or “optic flow” seems to be especially provocative of visual hallucinations in people with CBS or other disorders. I met one elderly psychiatrist with macular degeneration who had experienced only a single episode of CBS hallucinations: he was being driven in a car and began to see, on the edges of the parkway, elaborate eighteenth-century gardens which reminded him of Versailles. He enjoyed the experience and found it much more interesting than the ordinary view of the roadside.

    Ivy L., who also has macular degeneration, wrote:

As a passenger in cars, I began riding with my eyes closed. Now I often “see” a small, moving travel scene in front of me when my eyes are shut. I “see” open roads and sky, houses, and gardens. I do not “see” any people or vehicles. The scene constantly changes, showing unidentifiable houses in great detail sliding by when the car is in motion. These hallucinations never appear except when I am in a moving car.

(Mrs. L. also reported text hallucinations as part of her CBS, “brief periods when I would ‘see’ handwriting in huge letters across a large white wall, or the income tax figures imprinted on the drapes. These lasted several years, at intervals.”)

8. Such correlations involve sizable regions of the brain; they are at a macro level. Correlations on a micro level, at least for elementary geometric hallucinations, have been proposed by William Burke, a neuro-physiologist who has experienced such hallucinations himself, due to macular “holes” in both eyes. He has been able to estimate the visual angles subtended by specific hallucinations and to extrapolate these into cortical distances. He concludes that the separation of his brickwork hallucinations corresponds to the separation of the physiologically active “stripes” in the V2 part of the visual cortex, while the separation of the dots he hallucinates corresponds to that of the “blobs” in the primary visual cortex. Burke hypothesizes that with diminished input from his damaged maculas, there is diminished activity in the macular cortex, releasing spontaneous activity in the cortical stripes and blobs that give rise to hallucinations.