The Case of the Phantom Phantom Finger

By Neuroskeptic | March 10, 2012 1:21 pm

A “phantom limb” is the sensation that an amputated limb (or other body part) is still present.

They can be distressing, especially when they’re accompanied by pain in the “limb” which is not uncommon. The leading theory of why they happen is that the brain areas that used to receive sensations from the lost appendage respond to input “spilling over” from nearby brain regions.

Anyway, a phantom limb is bad enough, but a paper just out reports on the case of a phantom finger that was never there in the first place.

A woman, RN, was born with an abnormally short right arm; her right hand was also malformed, with a shortened thumb, no index finger, and immobile ring and middle fingers. Only the little finger was present and correct.

At the age of 18, she then had the misfortune to suffer a car crash; the injuries meant that her right hand had to be amputated. She soon found herself experiencing a phantom hand – with all five fingers. Three of them felt like they were normal length; the “thumb” and “index finger” felt shorter than normal, but remember that the original hand had no index finger at all.

RN also suffered from phantom pains and was distressed by the fact that the “hand” felt like it was bent into an impossible posture. Fortunately, the mirror box technique was able to set things right; while the phantom was still there, it was no longer painful, and all the fingers were the right length.

This is a remarkable case. The authors of the paper, Paul McGeoch and V. S. Ramachandran (perhaps the best known phantom-limb expert) say that it could mean that we’re born with an innate, hard-wired “body plan” in the brain, regardless of the way our body actually develops –

While RN’s phocomelic [abnormal] hand was present she did not experience any phantom sensations. Thus, although severely deformed, the mere presence of the hand was sufficient to inhibit the innate representation of her normal hand and prevent any phantom sensations from emerging, presumably from tactile, proprioceptive and visual feedback… the amputation of her hand appears to have disinhibited these suppressed finger representations in her sensory cortex and allowed the emergence of phantom fingers that had never existed in her actual hand.

They do consider alternative explanations though –

Clearly it is beholden on us to consider whether RN’s descriptions do not describe a genuine sensory experience, but rather are confabulatory in origin. We do not believe this to be the case, since if she were confabulating then it would seem unlikely that she should report that her phantom hand had five fingers, but that they were not all of normal length; if this were simply ‘wishful thinking’ then she would likely claim to have five normal length fingers. This appears a persuasive, although not definitive argument, against confabulation.

Seems like a fair assessment.

I don’t even know what you’d call the phantom “index finger”. A pseudo-phantom? A phantom phantom?

ResearchBlogging.orgMcGeoch, P., and Ramachandran, V. (2012). The appearance of new phantom fingers post-amputation in a phocomelus Neurocase, 18 (2), 95-97 DOI: 10.1080/13554794.2011.556128

CATEGORIZED UNDER: evopsych, mental health, papers
  • Ivana Fulli MD

    I would be tempted to conclude that something wrong of an epigenetic quality happened to her DNA (or whatever close to DNA) in the cells that were to produce her hand and fingers and not in the cells that where forming her brain sensitive cortex corresponding to the sensations in that hand and fingers.

    It also seems to me that we would need more proofs about the ways that kind of therapy works

    -if it really works-and that that article do not contribute to shed light on it.

  • omg

    I reckon we have an innate sense of space and time. We're wired to recognize spatial distances, symmetries, proximity cues etc. and this varies with time. For survival reasons perhaps. Wouldn't just be species specific. If we saw a chicken with a missing leg we might be wired to respond hey that cuckoo is not kosher. Better not eat it.

  • http://www.blogger.com/profile/17401232760394588049 John

    How about explaining this phantom!

    Phantom erection after amputation of penis. Case description and review of the relevant literature on phantoms.

    Several aspects were unusual, particularly the existence with phantom only in the erect state, and associated recrudescence of a preoperative painful ulcer.

    MID: 10068809 [PubMed – indexed for MEDLINE] Free full text

  • http://babblogue.wordpress.com LG

    Here is my personal weirdness: the Phantom tooth ! I had a painful cavity on my left molar and had it removed, a root canal performed, and tooth replaced by an implant. Yet, the “tooth” continues to hurt (and how!), although there are no nerves in there.
    The hardwiring upstairs is way to whacky ! And amazing.

  • Anonymous

    I haven't read the article. Have the authors discounted a possibility that the fantom fingers developed as a result of mirror-box treatment? What arguments, if any, do they provide against that?

  • Anonymous

    Unfortunately the amateur science reporters who write about subjects such as phantom limbs and mirror therapy don't read the literature and they don't interview the scientists who are doing the current research. They provide very little critical perspective.

    V.S. Ramachandran may be the best known “expert” on phantom limbs in the public's mind but much of what he has to say is hopelessly out of date. His original theory about phantom limbs was decisively disproven in 1996! Yet he continues to talk (and write)about the subject as though no research had been done in the past 15 years. If you are looking for current research on this topic you would be much better served reading papers published Herta Flor (University of Heidelberg)and Lorimer Moseley (University of South Australia). Always keep your skepticism sharpened. Phantom limb pain is a very complex and challenging subject.

  • http://www.blogger.com/profile/06647064768789308157 Neuroskeptic

    Anonymous: Well I'm always trying to sharpen my skepticism. If you have any other links or papers on that issue, please let me know either in a comment or an email…

  • http://www.priceperheadcostarica.com/ pay per head

    Well this is my first visit. Great stuff over the blog. Illustration has something special and I think we can't avoid this kind of initiative.

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About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.

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