Hallucinations

Where Mitchell’s observations, working with Civil War amputees, were of fresh, just developed phantom limbs, James was able to study a much more varied population (one man, in his seventies, had had a thigh amputation sixty years earlier), and so he was in a better position to describe the changes in phantom limbs over years or decades, changes which he described in detail in his 1887 paper on “The Consciousness of Lost Limbs.”

James was especially interested in the way that initially vivid and mobile phantoms often tended to shorten or disappear with time. This surprised him more than the presence of phantoms, which he felt was only to be expected with continuing activity in the areas of the brain that represented sensation and movement in the lost limb. “The popular mind wonders how the lost feet can still be felt,” James wrote. “For me, the cause for wonder are those in which the lost feet are not felt.” Hand phantoms, he observed, unlike leg or arm phantoms, rarely disappeared. (We now know that this is because the fingers and hands have a particularly massive representation in the brain.) He did, however, note that the intervening arm might disappear, so that the preserved phantom hand now seemed to sprout from the shoulder.³

He was also struck by the way in which an initially mobile phantom could become immobile or even paralyzed, so that “no effort of will can make it change [its position].” (In rare cases, he said, “the very attempt to will the change has grown impossible.”) James saw that fundamental questions were raised here about the neurophysiology of “will” and “effort,” though he could not answer them. And they were not to be answered for more than a century, until V. S. Ramachandran clarified the nature of “learned” paralysis in phantom limbs in the 1990s.

Phantom limbs are hallucinations insofar as they are perceptions of something that has no existence in the outside world, but they are not quite comparable to hallucinations of sight and sound. While losing one’s eyesight or hearing may lead to corresponding hallucinations in 10 or 20 percent of those affected, phantom limbs occur in virtually all who have had a limb amputated. And while it may be months or years before hallucinations follow blindness or deafness, phantom limbs appear immediately or within days after an amputation — and they are felt as an integral part of one’s own body, unlike any other sort of hallucination. Finally, while visual hallucinations such as those of Charles Bonnet syndrome are varied and full of invention, a phantom closely resembles the physical limb that was amputated in size and shape. A phantom foot may have a bunion, if the real one did; a phantom arm may wear a wristwatch, if the real arm did. In this sense, a phantom is more like a memory than an invention.

The near universality of phantom limbs after amputation, the immediacy of their appearance, and their identity with the corporeal limbs in whose stead they appear suggest that, in some sense, they are already in place — revealed, so to speak, by the act of amputation. Complex visual hallucinations get their material from the visual experiences of a lifetime — one has to have seen people, faces, animals, landscapes to hallucinate them; one has to have heard pieces of music to hallucinate them. But the feeling of a limb as a sensory and motor part of oneself seems to be innate, built-in, hardwired — and this supposition is supported by the fact that people born without limbs may nonetheless have vivid phantoms in their place.⁴

The most fundamental difference between phantom limbs and other hallucinations is that they can be moved voluntarily, whereas visual and auditory hallucinations proceed autonomously, outside one’s control. This was also emphasized by Weir Mitchell:

[The majority of amputees] are able to will a movement, and apparently they themselves execute it more or less effectively.… The certainty with which these patients describe their [phantom motions], and their confidence as to the place assumed by the parts moved, are truly remarkable … the effect is apt to excite twitching in the stump.… In some cases the muscles which act on the hand are absent altogether; yet in these cases there is fully as clear and definite a consciousness of the movement of the fingers and of their change of positions as in cases [where the muscles of the hand are partially preserved].