Simon Hoermann, Elizabeth Franz, and Holger Regenbrecht published an article, “Referred Sensations Elicited by Video-Mediated Mirroring of Hands.” With the abstract idea that humans could get ownership of their own limbs, even though their actually limb is not present. They would be able to feel their own limb by using mirror reflection. The downfall to this is that mirror reflection can be very limited when it comes to the transformation and context as it occurs in real life (Franz,2012). Mirror visual feedback (MVF) was used in this study, this type of therapy became possible in 1995 (Ramachandran,1995).
MVF was originally developed to help people deal with phantom limb pain, particularly in cases where a patient imagined that an amputated arm or leg was stuck in an uncomfortable position. MVF works as a manipulation of a mirror. How this box works is that a vertical mirror is placed upwards position between two boxes. This box has no front, this way the volunteers can place their hands separately inside the box.
The top of the box is also removed, because that is where the mirror is placed so it allows the volunteers to be able to see their hand movement. “Referred sensations, or sensations felt on sites on the skin which were not actually stimulated, have been studied in the context of mirror therapy since about 1996.” (Mcabe,1) It seems that in most studies they were unsuccessful when inducing the tactile sensation into healthy volunteers. The conclusion found for this is any sensation in the phantom limb can be unique and different in different people and environments. However, this was not the case for Ramachandran and Hirstein.
In their study, they were able to four out ten of their volunteers to elicit a RS (Hirsetin, 1998). There has been a lot of other research on this topic, such as Botvinick and Cohen’s rubber hand illusion. The rubber hand illusion is when you take a divider such a piece of cardboard to separate the hands. One of your hands is then replaced with a fake hand. Your real hand is than grazed with a brush to create sensation in your fingers. Then the rubber hand is grazed and you are able to feel it on your real hand. There has been other studies that have focused on perceived ownership of virtual or artificial limbs. Takasugi also did a study like this one.
He did two experiments with twenty-one healthy participants. In this study, they would place their phantom hand behind the mirror well watching their other hand be stimulated through the mirror. In the second study, he had sixteen participants. In that study he would use a rubber hand to replace the hand of the assistant. The result for both of these experiments showed Takasugi could elect an RS in all the conditions (Takasugi, 54-60).
However, this article looks into a different study. In this study the main question is, will the video-mediated system enhance one’s previous ownership and intensity of sensation in their phantom limb. This experiment involved twenty-one healthy volunteers. Out of the twenty-one volunteers four of them were left handed. There were three experimental conditions: the optical mirror condition, the video-mediated augmented reflection technology condition, and the video-mediated advanced augmented reflection technology condition (Regenbrecht,3).The optical mirror condition is when volunteers would place their hands in the outer right of the box and the left hand in the other woodbox. The woodbox would not be visible to volunteers they could only see their right hand through the mirror. In both the ART and advART conditions, volunteers would be asked to place their hands inside two of the black wooden boxes where they would not be able to see their hands.
They could only see their hand through the screen. However, in the ART condition volunteers would only be able to see the left side of the screen where they could see their right hand being mirrored and brushed. In the advART was almost the same thing but this time it was shown on the right side of the screen instead of the left. This study was measured in various ways.
When it came to measuring the RS there was three major measures. The first measure would be if the volunteers could tell the researcher what they felt on their left or right hand. The second, would be if the volunteer could describe the intensity of the sensation on a scale of zero to ten. Then, the third measure would be if the volunteer could locate where they felt the sensation. Afterwards, the volunteers were asked to participate in a verbal and written questionnaire. The questionnaire asked about the experiment and contained seven questions.
These questions would consist of asking the volunteers to compare the two different systems. They would also ask questions to see if the volunteers had any prior knowledge going into this study. Researchers were also interested in seeing if any of the volunteers played any computer games that might bias their results (Franz,2012).
There were also various experimental procedures. In this experiment there was three conditions. The first being the OMB condition which was the same conditions found in the Takasugi study (Takasugi, 2003). The second was the ART condition. This condition is where volunteers could view the mirror through the screen.
The third condition was the adv-ART condition, this condition would use the new finding of ART. Which was the cross-mirroring effect, meaning volunteers could view of their hands at the same time on two different left and right mirroring screens. All volunteers participated in all three conditions. The volunteers would place both their hands into the boxes.
The left and middle box were used for both the ART and adv-ART conditions. The OMB condition used the right and middle box. The volunteers were asked to not move their arms or fingers at all during stimulation. Researcher would then use a painting brush with a light touch, each finger of the right hand was stimulated twenty-five times at random. After every stimulation researchers would then ask the volunteers to describe the sensation they felt in their phantom left hand. In the OMB condition, volunteers would eiw their right hand being stimulated through the mirrored window. The ART condition was the same but instead of volunteers looking through the mirrored window they were asked to look at a computer screen that showed the hand being stimulated.
The adv-ART condition, volunteers could view both hands at the same time. The left hand on the right side of the screen and the right hand on the left side of the screen. The results show that there was no significant difference between the OMB and adv-ART. There was no difference in the stimulation of intensity.
It also seems that the questionnaire answers also showed no significant difference. However, this study was important because researchers found that the RS and the ownership hand are similar in both the OMB and adv-ART conditions. These results show similarities to Takasugi study, where about 95.2% of volunteers reported that the mirror image evoked an ownership feeling of their hand.
(Matsuzawa, 2011) All of these finding shows that the new ART setup can potentially be helpful in the future to help induce ownership of phantom limbs, which can then obtain to a positive outcome.