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- NEW YORK (Reuters
Health) -- Like victims in a horror film, patients with a rare syndrome
known as 'alien hand' feel disassociated from one of their own hands, insisting
that the hand is 'possessed' by a force outside their control.
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- The condition typically arises in the aftermath of brain
surgery, stroke, or infection. Patients can feel sensation in the hand,
but believe that it is not part of their body, and that they have no control
over its movements. In some cases, ''alien hands can perform complex acts
such as trying to tear clothes or undoing buttons,'' explain neurologist
Dr. R. Inzelberg and colleagues at Hillel Yaffe Medical Center in Hadera,
Israel.
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- Writing in the February issue of the Journal of Neurology,
Neurosurgery, and Psychiatry, the Israeli team describes a case of 'alien
hand' associated with a possible case of Creutzfeldt-Jakob disease (CJD),
a degenerative brain disorder caused by infectious particles called prions.
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- The patient in question, a 70-year-old Argentinean man,
underwent a swift neurological decline -- including hallucinations, memory
dysfunction, behavior change and alien hand -- possibly caused by CJD.
``At times,'' the researchers report, ``(his) left arm would spontaneously
rise in front of the patient during speaking.... He was unaware of these
movements until they were brought to his attention.''
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- Isolated reports have linked alien hand with CJD in the
past. In one case, ``the alien limb performed complex actions such as unbuttoning
(the patient's) blouse and removing a hair pin.'' In another, a woman found
herself ``powerless'' to prevent her hand from repeatedly touching her
eyes and mouth.
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- According to the study authors, various types of brain
injury appear to trigger distinct subtypes of alien hand. For example,
in right-handed persons, injury to the corpus callosum -- a bundle of nerves
connecting the two halves of the brain -- can give rise to ``purposeful''
movements of the left hand, while injury to the brain's frontal lobe can
trigger ''grasping'' and other purposeful movements in the dominant (right)
hand. In other cases, ``aimless movements of either hand'' occur in patients
affected by injury to the brain's cerebral cortex. And the authors note
that more complex alien hand movements -- such as unbuttoning or tearing
of clothes -- are usually associated with brain tumors, aneurysm or stroke.
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- In every case, patients retain sensation of feeling in
the affected hand or arm, but lose any sense of control over the renegade
limb. ``They may struggle to stop the movements,'' Inzelberg told Reuters
Health, ``restrain the limb, punish it, talk to it, personify or refer
to it as a third person. The may even say that an evil spirit exists in
the hand. In a sense the hand is the 'Other.'''
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- The study authors note that one common factor between
the diseases associated with the phenomenon is that all these disorders
involve several parts of the brain at once, suggesting that simultaneous
damage to the parts of the brain that control movement may be responsible.
In essence, Inzelberg explained, there is a ``disconnection between parts
of the brain which are involved in motor (voluntary muscle) control.''
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- Unfortunately, there is currently no treatment for alien
hand. According to the Israeli researcher, all patients can do to control
the problem is to keep the hand ``occupied'' by having it hold an object.
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- Based on their findings, the investigators advise that
Creutzfeldt-Jacob disease be added to the list of neurological disorders
that prompt 'alien hand.' Inzelberg says future studies are planned ``to
understand better the mechanisms involved in this rare condition.'' SOURCE:
Journal of Neurology, Neurosurgery and Psychiatry 2000;68:103-104.
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