Alien Hand Syndrome is a neurological disorder where an individual has no control over their hand and it seems to act independently from the rest of the self. The hand seems to be out of synch with the rest of the mind and body hence the term ‘alien’. Some individuals report having to restrain their own hand with their other (reminiscent of Dr Strangelove). Sufferers have reported a range of experiences from putting a cigarette in the mouth ready to light with one hand for then the ‘alien hand’ to remove it immediately Other experiences have been more menacing with the hand punching the self and in one case a woman woke up being choked by her own but alien hand.
Cutting the corpus callosum cured Karen’s epilepsy, but left her with a completely different problem. Karen told me that initially everything seemed to be fine. Then her doctors noticed some extremely odd behaviour.
“Dr O’Connor said ‘Karen what are you doing? Your hand’s undressing you’. Until he said that I had no idea that my left hand was opening up the buttons of my shirt.
“So I start rebuttoning with the right hand and, as soon as I stopped, the left hand started unbuttoning them. So he put an emergency call through to one of the other doctors and said, ‘Mike you’ve got to get here right away, we’ve got a problem’.”
Karen’s problem was caused by a power struggle going on inside her head. A normal brain consists of two hemispheres which communicate with each other via the corpus callosum.
The left hemisphere, which controls the right arm and leg, tends to be where language skills reside. The right hemisphere, which controls the left arm and leg, is largely responsible for spatial awareness and recognising patterns.
Cited from http://www.bbc.co.uk/news/uk-12225163
The causes seem to be solely down to neurological trauma in certain regions, especially in the connectivity between the two hemispheres, in particular the Corpus Callosum. Roger Sperry’s research into individuals who had their hemispheres disconnected (known as split brain) as an attempt to significantly reduce symptoms of epilepsy would have been prime candidates for such a phenomenon, but this is not the case, nobody seems to know why however they did exhibit a range of behaviours where one side seems to be unaware of what the other was doing.
A similar disorder is called anarchic hand syndrome.
The woman with the evil twin
Doctors in California have removed a tumour they have described as an “embryologic twin” deep inside the brain of a young woman.
Yamini Karanam, 26, a PhD student in Indiana, had been experiencing difficulties with drowsiness, reading and concentration.
The discovery was made when doctors performed a newly-developed form of surgery to remove the tumour.
The growth, known as a teratoma, had bone and hair.
Ms Karanam, a student at Indiana University, jokingly described the tumour to KNBC, a California TV station, as her “evil twin sister who’s been torturing me for the past 26 years”.
The tumour was found in Ms Karanam’s corpus callosum.
“This tumour was smack in the middle of that, so extremely deep in the brain,” Dr Hrayr Shahinian told the BBC.