Anton's syndrome

To the Editor:

Ring and Cooper's (1999) fascinating book on out-of-body experiences (OBEs) in blind people was reviewed by Harvey Irwin (JP, 64, 107-113), and this review was recently commented on by Philip Paul (JP, 64, 231-232). I would like to add a few spontaneous associations to selected points raised by these two writers.

"Mindsight" as perceptual-like impressions

In his review, Irwin used a very poignant term to refer to the quality of apparently visual experiences during OBEs; in speaking of perceptual-like impressions he makes clear that "out-of-body vision" must not be confounded with vision in any sense that the term is used in textbooks on perception, and not with residual vision in blind persons. Parapsychology and neuropsychology meet in the intriguing question as to where the perceptual-like impressions, phenomenally experienced as vision, might come from. The neuropsychological account is that they are synesthetic transformations of, for example, auditory and somatosensory perceptions. Once in awhile my colleagues and I see patients with seizure-related OBEs. Typically, these persons report that they observe, from a vantage point just under the ceiling, their bodies shaking and twisting on the ground. They "see" other persons entering the room (provided they hear them entering), and they "see" how these persons handle their own bodies (provided they feel the corresponding touch). A further, particularly revealing instance of mindsight, as neuropsychiatrists know the phenomenon, is found in the so-called Anton's syndrome, that is, the denial of one's own cortical blindness. Although completely blind, these patients continue to have the phenomenal experience of vision (and, with admirable consequence, they also neglect the fact that they continuously bump into objects!). If keys are held in front of these patients in an attempt to test their vision, these patients actually "see" the keys and provide meticulous descriptions thereof--but only if the keys are slightly moved to produce a characteristic sound pattern (Goldenberg, Miillbacher, & Nowak, 1995). They are equally convinced that they "see" the keys when presented with a book accompanied by the noise of jingling keys. Mindsight is the fascinating consequence of the human brain's capacity to reorganize its functional properties after the loss, transient or permanent, of one sensory modality. The question remai ns: Why should people who are blind from birth report a phenomenal awareness of visual aspects of the outside world?

Things never seen and body parts never felt

Irwin is certainly correct when he takes the existence of out-of-body vision, in people who were born blind, as evidence against a sensory basis "at least as we usually understand this expression" (p. 110). I also share his critical attitude toward Ring and Cooper's (1999) transcendental awareness model of blind persons' OBEs that can hardly be falsified. The sociocognitive account Irwin himself proposes (i.e., cultural and media influences on a person's expectation of what an OBE or near-death experience "should look like") may indeed be more appropriate, but even if it could be proved valid we still need to elucidate those brain mechanisms that turn expectations into perceptual-like impressions. Had we only dealt with phenomenal visual experiences after acquired blindness, the problem would not have been substantial; we know that, as a release phenomenon, "phantom vision" occurs rather frequently after either peripheral or central blindness (Schultz & Melzack, 1991). Phantom vision is in many respects simi lar to the phenomenal persistence of a body part after amputation, that is, phantom somesthesis or the phantom limb phenomenon. Contrary to most contemporary textbook information, phantom body parts can also be experienced by people with congenital absence of limbs (Brugger et al., 2000). This observation does not question the important role of decades of sensorimotor limb experiences in the genesis of amputation phantoms. It just means that bodily experience is no necessary requirement to feel a phantom of one's entire body (an astral or parasomatic body in parapsychological terminology). In fact, cases of out-of-body or related doppelganger experiences in persons who lack a limb, but whose phantom body is normally shaped, are not unique in the neurological literature. As theoretically important as they undoubtedly are, observations of OBEs in the congenitally blind are predicted by current neuropsychological theories of bodily representations.

From "seeing" to seeing: the virtual reality of OBEs

I now turn to the very stimulating thoughts offered by Paul. He argued that the way deaf people learn to hear after implantation of a cochlear ear may be pertinent to the question of how blind people get to "see" during an OBE. He speculated that, if there were such a thing as a "cochlear eye," the comparison would have even been more helpful. In fact, there are a number of neurophysiologically based techniques that have been used to teach blind persons to "see" for the first time in their lives. Again, this "seeing" is a perceptual-like impression which--and this is the main point of interest to blind people--helps the patient to successfully avoid obstacles. One such technique is called the tactile vision substitution system (Kaczmarek, Webster, Bach-y-Rita, & Tomkins, 1991). The blind person carries a video camera on the top of his or her head, and a computer converts brightness information into pressure stimuli of different strength that are applied over a certain area on the person's skin (e.g., when lo oking at a bright full moon in the middle of an otherwise dimly lit sky, a high-pressure circular patch is felt within a surround of light pressure). As the fascinating first-hand accounts of congenitally blind people clearly show, after prolonged exposure to such cutaneous stimulation the individual will eventually refer to his or her perceptual experience as "seeing," forgetting more and more that what is actually provided is a complex array of mere tactile stimuli.

The experiences with ear implants, competently summarized by Paul, have taught us a lesson: Hearing cannot be simply "switched on" by a cochlear trigger, it has to be learned. This is because hearing is not a property of the ear (which is a mere sound wave analyzer) but a property of the brain as a machinery that converts noise into meaningful percepts. The same holds for the various sensory substitution systems designed to gain sight; it is not the eyes that see, but the brain. Thus, "audition," "vision," and "somesthesis" in the experiences of deaf, blind, and tetraplegic persons, respectively, remain perceptual-like impressions, however close an individual's phenomenal awareness may be to the real thing. With special reference to the multisensory quality of OBEs, they must best be conceived as a person's experience of a virtual reality created not by the respective sensory organs but by cortical association areas. Having said this, I found one thing puzzling in the OBE reports of Ring and Cooper's (1999) participants: Some very typical nonvisual features that typically accompany normal people's OBEs seem rather underrepresented. One example is the ringing, buzzing, or musical sounds that often precede out-of-body states (Brugger, Regard, & Landis, 1997; Rogo, 1975); another characteristic feature is the "vibrational state" (Buhlman, in press). I do not see why these auditory and vestibular sensations should not be an important part of the OBE, also in blind persons.

I have the following impression about Ring and Cooper's (1999) work: In the words of still another commentator on their book, "I believe it just may become one of the most important publications in contemporary parapsychological research" (Parker, 2000, p. 92). In having already attracted many a parapsychologist's attention, the book is on the best way to actually reach this status of importance. What I consider now important is that it will also find its way onto the desks of open-minded neuroscientists. They should appreciate the phenomenological value of the contribution and recognize that conceptualizations of an "astral body" as an exact duplicate of the physical body may not be that different from conceptualizations of a "phantom body" as a central bodily representation. On the other hand, in order to reach a "breakthrough" in OBE research, parapsychologists will need to dig much deeper into the neurological literature than they hitherto have. Ring and Cooper's (1999) book seems an ideal springboard fo r a joint endeavor to be undertaken by parapsychologists and neuroscientists.

PETER BRUGGER

REFERENCES

BRUGGER, P., KOLLIAS, S. S., MURI, R. M., CRELIER, G., HEPP-REYMOND, M.-C., & REGARD, M. (2000). Beyond re-membering: Phantom sensations of congenitally absent limbs. Proceedings of the National Academy of Sciences of the United States, 97, 6167-6172.

BRUGGER, P., REGARD, M., & LANDIS, T. (1997). Illusory reduplication of one's own body: Phenomenology and classification of autoscopic phenomena. Cognitive Neuropsychiatry, 2,19-38.

BUHLMAN, W. (in press). The secret of the soul. New York: HarperCollins.

GOLDENBERG, G., MULLBACHER, W., & NOWAK, A. (1995). Imagery without perception--A case study of anosognosia for cortical blindness. Neuropsychologia, 33, 1373-1382.

KACZMAREK, K. A., WEBSTER, J. G., BACH-Y-RITA, P., & TOMKINS, W.J. (1991). Electrotactile and vibrotactile displays for sensory substitution systems. IEEE Transactions on Biomedical Engineering 38, 1-16.

PARKER, A. (2000). Book review. European Journal of Parapsychology, 15, 92-93.

RING, K., & COOPER, S. (1999). Mindsight: Near-death and out-of-body experiences in the blind. Palo Alto, CA: William James Center for Consciousness Studies.

ROGO, D. S. (1975). Some "musical" out-of-the-body experiences: A brief analysis. Parapsychology Review, 6, 19-20.

SCHULTZ, G., & MELZACK, R. (1991). The Charles Bonnet syndrome: Phantom visual images. Perception, 20, 809-825.

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