Supernumerary Phantom Arm Replaces Paralyzed Arm [phenomena]

[frameacloud]

Trigger warnings for this article: unusual psychological phenomena, unusual neurological phenomena. Safe for work.

A “phantom limb” is usually a body part that is subjectively sensed by an individual where a corresponding physical limb is not extant.  In one unusual case, a 64 year old woman developed a phantom arm when the corresponding arm was present but paralyzed by stroke.  They call this third arm a “supernumerary phantom limb” (SPL), which is apparently unusual but not unique.  Its traits are also unusual: she can see it, she can move it, and she can use it to scratch an itch.  Her experiences have been objectively confirmed by means of scans that show intriguing kinds of brain activity while she uses the ghostly arm.  However, is this for real?

When this piece of news was recently featured¹ on the popular blog, BoingBoing, they linked to an article² on SwissInfo (“an enterprise of the Swiss Broadcasting Corporation”) that was published on April 1^st.  That’s a suspicious date to publish any information at all, especially of an outlandish nature.  Could this phenomenon be an April Fool’s hoax?  Perhaps not: it seems that it wasn’t invented on April Fool’s Day.  Another article³ about the same woman’s SPL was published earlier in Science Daily, in March.  This article links to the original reference⁴ in the Annals of Neurology, the “official Journal of the American Neurological Association,” having been received last September.  It’s safe to assume that a peer-reviewed journal is a reputable source.

Amazingly, it’s possible to confirm someone’s subjective sensations of a phantom limb.  She’s not just claiming to be able to see and feel it: it’s been scientifically proven that she can.  The aforementioned Science Daily article summarizes what was observed in the woman’s brain scan: “imaginary movements of the paralyzed left hand showed dominant activation in areas associated with movement in right side of the brain.  When asked to scratch her cheek with the SPL, areas of the brain associated with movement and vision were activated, which confirmed her report that she could see and move her SPL.  In addition, a measurable sensory response was also detected when she scratched her left cheek with the SPL.”  Her sensations are as real as she says they are, even though the SPL itself is not perceived by others.

Consider the philosophical implications.  Science tells us that if we mean to seek truth, we should look to those physical things which can be perceived by the five senses, and which can be measured by devices, because these are the things that can be proven real.  Meanwhile, many spiritual concepts are necessarily beyond objective proof, because spiritual things reside outside of the five senses, and cannot be measured by the gadgets that supplement our senses.  This means that we can't be as certain of the truth of spiritual things.  It’s a very practical line of reasoning.  What, then, do we make of this?  This woman’s senses are telling her that this arm exists, and it was confirmed that her nervous system does indeed perceive it.  In a certain way, her SPL is adequately real: it’s right there, it is sensed and measured, and nobody was lying about it.  What is to be believed, when even these five senses can give information so different from what would be objective truth?  If any person found that xir sensory information differed from that of other people, should xe place more confidence in xir own senses, or should xe rely more on the second-hand reports of other people?

Therianthropes and otherkin may be saying, “A supernumerary phantom limb, an SPL? So that’s what it's called.”  It’s a familiar concept to them.  Some therians and otherkin experience phantom limbs that correspond with limbs that have never been present on any human body, such as wings.  A few of these people even describe sensations as vivid as those of the woman in this study.  (You’re bound to find them while browsing through Winged Eternal,⁵ a forum for discussing phantom wings.)  Speaking as someone who has been actively involved in their community for almost a decade, I haven’t heard of any therians or otherkin who have had their SPL sensations examined by brain scan, like this woman.  If someone performed such a study on a therian or an otherkin, that could be big news.

- O. Scribner

( Sources )