Phantom limb research

What’s new?

Research results

Access to detailed results


Phantom Limb Research Results
(updated 01/03/10 --» What’s new? )

This page the results of our phantom limb research to date.
  1. Physiological condition of M.G.’s left hand adactylia (2007)
  2. Locating and mapping phantom finger “ends” through right finger “touching” (2007)
  3. Preliminary tests of M.G.’s sensations when “touched” by an object (2007)
  4. Preliminary tests of M.G.’s interactions with different areas of another subject’s face (2007)
  5. Tests of M.G.’s interactions with different points on the back of the head (2007)
  6. Tests of M.G.’s interactions with a different subject (2007)
  7. Comparison of interactions with S.M. on the same points, 2007 versus 2009
  8. Different subjects also reported complex visual experiences (2009)
  9. Subjects had a wide range of sensations and physical reactions (2009)
  10. Preliminary blinded trials of randomized “touch” and “no touch” cases (2009)
  11. M.G.’s own sensations and physical reactions during the tests (2009)
  12. Tests of possible physical interactions with M.G.’s phantom fingers (2009)
  13. Access to detailed research results

PLEASE NOTE: The videos and photographs on this page are copyrighted and are presented here to assist other researchers to analyze our research and provide comments. The videos and photographs are not to be copied, saved or republished without express written permission of the authors.

Comments on our work are welcome! Please feel free to comment on our Discussion Group on the Self-Conscious Mind. More extensive, detailed experimental results are available to people with a legitimate research interest. See below for access details

Robert and Suzanne Mays

What’s new?
  • 01/03/10 - added link to access to detailed research results
  • 09/27/09 - clarified subject's reaction to “touch” with dizziness and headache, based on subsequent interview with subject
  • 09/09/09 - reorganized page; split off and summarized results from detailed 2007 page; added summary research results from 2009 sessions

1. Physiological condition of M.G.’s left hand adactylia (2007)

We did not perform a physical examination of M.G.’s left hand but it appears from visual examination that there was initial development of the five metacarpal bones which was arrested during the first trimester. The thumb metacarpal appears to be nearly completely developed, whereas the finger metacarpals appear to have reached only about half of their development. The finger “buds” appear to be the ends of the shortened metacarpal bones or rudimentary proximal phalanges. M.G. has considerable flexibility in the use of her palm, indicating muscle and ligament development and the flexible movement of the metacarpal bones.

    Side-by-side comparison of left and right hands:
Subject's hands, palms up
full image

   Side by side comparison of left and right hands  
Subject's hands, palms down
full image

2. Locating and mapping phantom finger “ends” through right finger “touching” (2007)

2007: M.G. “finding” her fingers - first procedure: With eyes closed or looking away, M.G. went through the process of feeling where the “ends” of her phantom fingers are, by pulsing them with the tips of the right-hand fingers. The “ends” appear to be somewhat farther out than where her fingers would normally be. M.G. can feel something more subtle even further out than the “ends” of her phantoms. Her right finger tips feel a warmth and resistance at the point of “contact” with the “end” of the phantom finger. Physical sensations are felt when activating the finger “end”: (1) a tingling in the corresponding finger bud, (2) a warmth and pressure in the left palm, and (3) a sensation on the outside surface of the arm going up the forearm to a specific spot in the outer upper arm. These latter rising sensations can sometimes go up into the left jaw and head. The left arm sensation is somewhat masked when the left arm muscles are holding the arm up, as opposed to having the arm rest on something. After the exercise there was a residual warmth and an increased circulation in the finger buds.
Subject "finding" her fingers - procedure 1
Streaming video
(11.4 MB, 608)
2007: M.G. “finding” her fingers - second procedure: M.G. usually feels a streaming sensation of her phantom fingers where there are two points, a weaker point, about a foot away from the “end”, where there is the first sensation of the finger, then a stronger point much closer where the finger “end” is felt, where there is a firmer sensation both in the right finger and in the finger bud. From the questionnaire M.G. had filled out (Q12): “The right fingers kind of make “ends” on the phantoms. Usually I feel [the phantoms as] a streaming out [and] the right hand touches where the tips of the fingers would be. The feeling actually starts further out – that’s what I mean by [my left hand, for as long as I can remember, always felt] “big”  but closer in it’s heavier, thicker. There’s a dense place, about where the finger “ends” would be. If I go further in [from the “ends”], hmm, that’s interesting.” Subject "finding" her fingers - procedure 2
Streaming video
(12.1 MB, 653)
Later in the session, M.G. clarified that pulsing and pushing further into her phantoms beyond the “ends” produces a more intensive sensation of “dih, dih, dih”, like a touching or tapping or a kind of magnetic resistance (the same poles of two magnets pulsing together), which is felt in the finger buds. It almost feels as if the phantom fingers are being pushed from their normal place further up her arm.

Comparative finger sensitivities over time:

  • 7/25/07: Thumb=6, Index=6, Middle=4, Ring=3, Pinky=4
  • 9/10/07: Thumb=6, Index=6, Middle=5, Ring=3, Pinky=3
  • 9/11/07: Thumb=6, Index=2.5, Middle=4.5, Ring=3, Pinky=2.5 (this session)
  • Average: Thumb=6, Index=4.8, Middle=4.5, Ring=3, Pinky=3.2 (N=3)
2007: Map of phantom finger layout after “finding” them. The phantom “ends” generally appear to be longer than the physical fingers of the right hand, by only a small amount (ring finger) to perhaps 2" (thumb). The numbers by each finger indicate the approximate apparent height of the “finger” tips above the table at the time of measurement, ranging from 1/4" to 2".

In an earlier mapping there was also apparent curling up of the fingers above the table, indicating that the procedure to find how long the phantom finger are can be problematic. A better procedure may be to measure the fingers with the palm down.

Phantom finger layout
full image  
2007: A drawing of the apparent “field of sensation” around M.G.’s physical left hand, showing the outer arc and the inner “ends” of her phantom fingers. In “finding” her phantoms, M.G. first feels the general outer arc (a weaker sensation) but in that area there is a place where she can feel something in the hand. This is the “stream” of the phantom finger, which M.G. can trace, following the sensation down to the “end” of the finger. The fingers are usually more diffuse and big, streaming out when they are first “lit up”, and then by interacting with her right fingers, they form up and become more defined. The fingers appear to be able to bend and curl up toward the palm but M.G. has never felt the fingers bending “backwards”. M.G. can use objects like a table to “activate” her fingers but the table interaction feels more vague if the fingers are not activated first by her right hand. In any case, the phantoms appear to become defined by interacting with something “meeting” them. Otherwise they are “streaming”, or they are not sensed at all because they have retracted or retreated (perhaps up the arm to the upper arm) and need to be “lit up” or “called out”. Apparent "field of sensation" around physical hand
full image

3. Preliminary tests of M.G.’s sensations when “touched” by an object (2007)

M.G. demonstrated that sensations were subjectively felt from interactions with objects. She sensed a difference between “touching” her fingers by an object (a metal stapler) and the researcher’s hand. With the hand, the difference was clearly evident of a more solid, “harder”, “thicker” feeling in the palm of the left hand, more like pressure, and a strong pulling on the thumb finger bud. The object had a different effect, making her finger bud twitch and felt less “direct” and more “remote”. At the end of the session, M.G. reported that her hand was very stimulated, perhaps overstimulated, with residual buzzing felt in the physical hand between the index and the thumb finger buds. 

4. Preliminary tests of M.G.’s interactions with different areas of another subject’s face (2007)

M.G. touched a second subject (researcher S.M., age 59), touching eyes, ears, nose, lips (presumably the tactilely sensitive areas of the face). A number of different sensations were reported by S.M. (shadows or darkness, warmth, brightness, dark round disk with a white ring around it). Latency was observed to be 3-4 seconds generally but sometimes 10-15 seconds. The variability of responses and the types of responses suggested to us that visual sensations probably involved interactions with brain regions or the retina. 

5. Tests of M.G.’s interactions with different points on the back of the head (2007)

The motivation for this session was to test the idea that the sensations researcher S.M. was reporting were due to interactions with tactile nerves in the skin (warmth, pressure) and with the brain (inner visual images). Therefore, “touching” of the head more directly in the brain regions might elicit more of the inner visual images. This proved correct, particularly with point #9, described in more detail below. 

Phantom limb "touch"
Streaming video (2.2 MB, 1’46)
Phantom limb "touch" 2
Streaming video (3.8M, 1’49)
M.G. can also “touch” another person and the “touch” is felt, especially when the other person’s head is “touched”. Here, a point in the right occipital/parietal area is “touched” and a visual image is perceived, similar to the images perceived with electrical brain stimulation. The image is perceived almost immediately when M.G. moves her hand in closer (a “charge” going right to left, a stream of light like a sword).

Another area is “touched”. Note the immediate reaction in subject S.M. when M.G. moves her hand closer in: the shoulders raise and there is an immediate response (perceiving a “beam” of dark rich black, later superimposed with a black disc with a white rim or corona around it)
A total of 9 points were “touched” (two points on the sides are not shown). The images perceived were drawn and described in detail: 
  • Black circles with a white ring, black swords with a white outline (several instances each)
  • Point 9 (blue) was a very strong experience: a black column rising through the body followed by a brilliant white light filling the head, also felt physically in the body and head. “It’s dynamic, it has a movement, like I am moving (upward) through it, with a light streaming out. My whole head, my whole skull is just white, just filled with light, with my whole skull feels like it’s being energized, with a pulsing of the skull.”
Points "touched" at back of head   Drawings of visual sensations experienced

Point 9 reported sensations (streaming audio, 1.7 MB, 2'21)
Point 9 description (streaming audio, 6.1 MB, 8'20)

6. Tests of M.G.’s interactions with a different subject (2007)

We also had M.G. “touch” a different subject, researcher R.M., age 61. M.G. “touched” four points on R.M.’s head, similar to points 5, 6 and 9 for subject S.M. (shown below) and also a point from the front, between the eyebrows. There were only two visual sensations: a subtle white clouding of the visual field with the eyes open, starting on the right visual field and moving to the left field, when left rear point was “touched”. When the point between the eyebrows was “touched”, with the eyes closed, R.M. perceived inwardly a single arc of color that started from the bottom of the visual field and moved slowly up, changing color as it moved up.

The drawing of the visual image when R.M. was touched between the eyebrows. There was a single arc of color moving from below upward, changing color as it moved, until it disappeared at the top of the visual field.
Drawing of visual sensations experienced - RM

7. Comparison of interactions with S.M. on the same points, 2007 versus 2009

Subject S.M.’s responses when M.G. “touched” the same points on the back of the head in 2007 versus 2009 were somewhat similar (in two cases S.M. gave very close to the same wording). However, the points in 2009 appeared weaker with fewer visual sensations. The points tested both years were:

Points "touched" in 2007 - back Points "touched" in 2007 - left side Points "touched" in 2007 - right side
Top row, left to right: 5, 2, 4, 6.
Bottom, L to R: 1, 9 (blue), 3.
Red point is #7 (approximately over left temporal lobe). Yellow point is #5 Top row, L to R: points #4 (yellow), #6 (yellow) and #8 (red, over right temporal lobe). Bottom is #3 (yellow).

In 2009, we tested all of the points on the first day and repeated selected points on the second day. On the repeated points the sensations were even weaker than the previous day, except for two repetitions (points 6 and 9) which are worth including for further comparison. The weaker sensations were probably due to not having M.G. follow a fixed procedure to “prepare” her phantom fingers. Also as M.G. grew tired during a long session, her phantom fingers appeared to weaken, both subjectively to M.G. and objectively in the sensations reported by the other subject. On subsequent days, we instituted a specific protocol for M.G. to follow to “focus” her fingers by drawing out all five fingers before she started working with a subject. We also noted that the longer the stimulation, the stronger the sensation that was experienced:  the sensation built up and got stronger from 10 sec to 1 min.

Pt 2007 Description Repeat 8/4/2009 Comparison Repeat 8/5/2009
1 Activation of the sinuses in the center of the face (eyes open) Pressure in eyes and sinus areas Very similar  
2 Energy coming out of the top center of head Top of the head felt like a lid opening. Pressure, pleasant feeling Very similar  
3 Activation (energizing feeling) of sinuses behind both eyes, activation in center of head (charged feeling) Jaws tingling, pressure in eye sockets Somewhat similar  
4 Warmth, stream of light from right to left: like a dark sword shape with shimmering white outlining it (inner visual image “added to” normal visual field) Pressure, tingling in right eye socket and upper right part of the brain Dissimilar, non-visual Pressure top of head, light at end of a tunnel
5 Beam of dark black on left side of visual field, then black disk with white ring or corona around it  Left eye, head expanding, opening Dissimilar, non-visual  
6 Again blade or sword of darkness with white on the edges, going from right to left, stimulation of both eyes On the right a white thin, vertical light, pressure on the right Somewhat similar: both are visual, with white  
7 Strong warmth radiating into the head, felt behind the ear (not on the spot “touched”) Left, pain on top, pressure from left to right through whole head. Top of head, mostly to left, a kind of throbbing “nerve” pain, lingered for some time afterward. Dissimilar  
8 Warmth in the area, again the dark sword with white on the edges, a feeling of being charged in the area “touched” and a little to the left A tone “trying” to sound. Prickling pain down right side of neck. (Took relatively longer to feel any sensation.) Dissimilar, much weaker, may have not touched same area  
9 Opening of a channel of darkness in solar plexus (abdomen) with shimmering white light surrounding it, like a column; the top of the channel (in the head) is exploding light. It is like going up a tunnel with light at the top. Growing pulsation, pressure in the middle-top of head. Felt like a flowering stimulation, vitalization of brain. Lingered for some minutes afterward. Very pleasant feeling. Similar but relatively weaker Pressure in center/top of head to the heart - feeling of centeredness, opening of the heart

8. Different subjects also reported complex visual experiences (2009)

Two out of six subjects in addition to S.M. reported similar responses to S.M.’s visual responses, with striking and sometimes complex visual experiences. Visual sensations occurred with the eyes open but were generally enhanced when the subject’s eyes were closed. Where we tried to repeat “touching” the same point more than once, the subject reported similar responses in each instance.

Subject A.G. visual sensations
Subject A.G., age 56, visual impressions (eyes closed)
Streaming video (1.5 MB, 0’43)
Subject F.S. visual sensations
Subject F.S., age 18, visual impressions (eyes closed)
Streaming video (3.3 MB, 1’23)
A fountain of white light emanating out of the top of my skull and flowing down on a diagonal to the bottom right; kind of like fireworks -- the middle of a sparkler. When this point was repeated later, A.G. almost immediately said: I have this curious image more from the bottom of my skull, light streaming up like vertical search lights, and warmth/tingling over the right side of my head and a lot of sunshiny color. (With eyes open, the visual sensation was not as pronounced but returned when the eyes were closed again.) (Subject is speaking very softly) Black surrounded by purple is flowing up like a lava lamp. And I keep seeing these trees, biological tree shapes but in black silhouette, moving from lower left to upper right and turning into just black bits. (This is just a small segment of a continuous stream of visual sensations the subject reported. At the beginning of the trial, with eyes open, the subject saw almost immediately “some wavy things across my vision” and somewhat later, diagonally falling heat waves.)

9. Subjects had a wide range of sensations and physical reactions (2009)

Different subjects report different physical reactions, generally characteristic of the subject, including strong sensations of warmth or a sensation of water cascading over the head, a few cases of sharp, almost painful sensations, a sense of the head being pushed to one side, the eyelid twitching, the ear “popping”, and the stomach “growling” as a response. Frequently, strong sensations were reported lingering for several minutes after the trial ended. The responses for different subjects appear to have different latencies of responding, ranging from about 4 seconds to sometimes longer than 30 seconds. One subject reported experiencing a strong headache starting right after the session, that appeared related to dizziness felt during the session. Subject took ibuprofen and had a nap in the afternoon but still felt headachy and went to bed early. Headache was resolved in the morning. It is not entirely clear if the headache was causally connected to the“touch” interaction, since subject had only 3-4 hours’ sleep the night before.

The following sequence (subject E.L., age 21) was taken from a trial  “touching” the back of the head with four phantom fingers. There was a noticeable increase in flushing of the cheeks, the side of the neck below the ear, the upper back and the upper chest. After the trial, the subject was literally ruddy on the cheeks and upper chest. This condition lasted several minutes after the trial.

Trial at 0:06 Trial at 2:19
Trial at 0:06. Cheek starts out  somewhat flushed.
Trial at 2:19. Sensation felt in forehead
Trial at 3:01 Session at 4:47, just ended
Trial at 3:01. First mention of sensation of warmth. Additional flushing first noticed. Trial ended at 4:47. Deep flushing noted on cheeks, side of neck and the nape.
          • 0:00 Start, eyes are open. Cheeks start out somewhat flushed.
          • 0:48 Scalp on top of head is tingling. Subject instructed to close eyes.
          • 1:51 Sensation felt inside the forehead.
          • 2:40 Sensation inside forehead is a “feathery feeling like when I am on the verge of sleep”.
          • 3:00 Warmth, too. (First mention of warmth.)
          • 3:10 Warmth is getting stronger. (Flushing along the side of the neck first noted.)
          • 3:45 Warmth is cascading from the top of head down to the cheeks.
          • 3:55 Warmth is going down further.
          • 4:20 Cascading feeling of warmth is mostly in the front and on the sides.
          • 4:40 It’s a pleasant feeling, but it’s very hot now. (Cheeks are very flushed.)
          • 4:47 Trial ended
10. Preliminary blinded trials of randomized “touch” and “no touch” cases (2009)

We tried two preliminary single blinded trials of randomized “touch” and “no touch” cases, providing immediate feedback to the subject (n=7 and n=6). The two subjects got nearly perfect scores detecting a phantom finger touch versus a control (a leather mitten held on a yard stick). The subjects’ perceived strength of sensation also corresponded well with M.G.’s perceptions of the strength of the “touch”. In both of these cases, the strength of the sensations was generally weak to strong. The sensations were not visual but rather a tingling or pressure or a sense of the head being rotated. 

For subject D.S., age 17, we selected a previous point (#5) at the back of the head, eyes open, that produced a “very strong” sensation of the head being pushed to the right. M.G. used a sequence of randomly generated 1’s and 0’s to determine whether to “touch” or use the control. The timing of each step of the trials was kept constant and M.G.’s movements were also equivalent between “touch” and “no touch” trials. The thumb of the leather glove and M.G.’s thumb bud were kept at approximately the same distance from the back of the subject’s head. D.S. was told after each trial whether the trial had been “touch” or “no touch”.

"Touch" trial "No touch" trial
Subject D.S. “touch” trial Subject D.S. “no touch” trial

Trial D.S. reported  strength D.S. comments M.G.comments Correct?
“Touch” 5 Back left of head: feeling of pushing/ROTATION to the right and slightly down, dizziness on left if attempt to counter the feeling of rotation   Yes
“No touch” 0     Yes
“Touch” 3 Sense of head being rotated to the right, a little fainter than previous.   Yes
“Touch” 2 Ditto, weaker still than the previous weaker for me Yes
“No touch” 0     Yes
“Touch” 1 Very faint feeling of pushing to the right. -- weak -- No, but correlated

The reported strength is on a scale of 0 to 5: 0=None, 1=Faint, 2=Weak, 3=Moderate, 4=Strong, 5=Very strong. In scoring whether a sensation was correct, we used the criteria that a strength of 0 - 1 is a “no touch” and >1 is a “touch”. The last trial thus was not correct. However, note that the “touch” was perceived by both subjects as very faint or weak and that the reported strength of the “touch” trials progressively declined. This series of trials was done at the end of the second hour-long session of the morning and M.G. reported that she was getting tired. The subjects took a break between trials 4 and 5.

This preliminary experiment was done informally, so no conclusion can be drawn. In the future, experiments of this sort need to be double blind, with stricter controls to eliminate other perceptual cues such as peripheral sight and hearing. Further work needs to be done to validate a proper control for the “no touch” case, such as the glove held at a distance, that does not result in false positives.

11. M.G.’s own sensations and physical reactions during the tests (2009)

M.G. had numerous reactions and sensations while “touching” other subjects, including a strong sense of warmth or light when working on what she felt were “strong” points on the other subject and twice heard a tone (middle C, d’) with an electrical hum quality. M.G. noted many times that what the other subject reported corresponded or correlated to her own specific experiences. In some cases, M.G. felt that she had “touched” and “felt” the other person’s brain within their skull. We also noted that M.G. frequently had nasal congestion after a subjectively felt “strong” “touch” trial and had to blow her nose.

12. Tests of possible physical interactions with M.G.’s phantom fingers (2009)

We have tested possible physical interactions three ways so far, all with negative results:
  • In 2008, we conducted an experiment to see if there was any interaction of the phantom fingers with fog generated from dry ice and warm water. This experiment was motivated by the story of an NDE involving apparent interaction of the NDEr’s “body” with fog on a cold night. The NDEr jumped up and down and the “jumping fog” was seen by another man. M.G. activated her phantom fingers as usual and placed her hand in the dry ice vapor. There was no effect at all. The situation in the NDE was somewhat different in that the NDEr’s “movements” were involved and M.G. is not able to move her phantom fingers, which are subjectively frozen in position. 
  • We tested interaction with light in an interferometer.There was no perceptible change in the interference pattern when M.G. placed her phantom thumb within the laser light of either leg of the interferometer or when she “touched” the laser spot on the splitting mirror. 
Interferometer setup - light experiments
Interferometer setup for light interaction experiments
Streaming video (11.0 MB, 4’29)  Full image
  • Interaction with a physical object: We arranged an interferometer with one of the mirrors suspended from two threads such that any slight movement would cause the laser light to go out of phase. We noted that even “at rest” there was an oscillation of the interference pattern in and out of phase, probably due to random vibrations of the mirror. There was also no perceptible change in the interference pattern when M.G. “pushed” her thumb and other fingers against the mirror, that is, the oscillations in and out of phase did not measurably change.
Interferometer set up 2, without cover
Interferometer set up, without cover
Streaming video (2 MB, 0’48)  Full image
Interferometer setup 2, with cover
Interferometer set up, with cover
Full image
Interferometer setup 2, with cover, detail
Interferometer set up, detail of window to suspended mirror. Full image
Interferometer setup 2, with cover, detail
Interferometer set up, detail of mirror suspended in mineral oil. Full image

Interferometer movement test
Interferometer movement test
Streaming video (7.6 MB, 3’08)

Conclusion: To the level of precision and care that we were able to accomplish with this apparatus, we detected no effect of interaction of the phantom finger regions with laser light or with a physical object. It is very possible that measurable effects could be detected with more precise equipment or a better constructed arrangement.

Access to detailed research results
For privacy considerations for M.G.and the other subjects, we wish to provide access to the more extensive, detailed experimental results only to those people with a legitimate research interest. If you are in this category, please contact us for access details. We also welcome your comments and can provide further details upon request.

Copyright © 2007-2010 Robert G. Mays and Suzanne B. Mays

Return to top