An individual who has the medical condition termed "alien hand syndrome" believes that their physically real and existing hand, does not belong to them. Their hand can apparently perform all on its own volition.
Contrast this with an individual who suffers from phantom limb pain of the hand. An amputee with a missing hand feels sensations from a missing limb, as if the limb were still physically present.
With the recent findings of neuroscience, relating to out-of-body experiences and the sense of self (see Keith Basterfield's excellent blog at:http://anomalies-australiancomments.blogspot.com )
both 'alien hand syndrome' and 'phantom limb pain' can be seen as bodily-self image issues. With 'alien hand syndrome' your brain is telling one hand of yours that it does not belong to you, i.e. does not form part of your body self image; with phantom limb pain of a hand, your brain continues to tell you your hand is still there - still part of your body self image.
An extension of this concept occurred to me while I was reading the latest OBE scientific literature. It may explain why some UFO abductees and contactees speak of their belief that they are not human. They talk of the sense that they do not belong, and in fact must therefore be of extraterrestrial origin.
Could this feeling of being 'alien' indicate that the bodily self image within the brains of these individuals has been totally distorted? They would then not feel the sense of 'self' which other people do?
It would certainly be a much more mundane explanation than that they are really from out there.