Cause of alien hand syndrome determined

GENEVA, Switzerland, July 17 (UPI) -- A Swiss-led research team has discovered the cause of alien hand syndrome -- a rare neurological disorder that causes involuntary hand movements.

People suffering the disorder might sometimes reach for objects and manipulate them without wanting to do so, even to the point of having to use their healthy hand to restrain the alien hand.

The researchers -- led by Frederic Assal of University Hospital in Geneva, Switzerland -- identified the areas of the brain involved in both voluntary and involuntary movement, finding the neural activity is restricted to the primary motor cortex during the unconscious motor activity seen with AHS.

"These data open new perspectives for the comprehension of neurological and neuropsychiatric disorders associated with abnormal motor control or abnormal awareness of action, such as utilization behavior, phantom limb ... or delusions of control in schizophrenia," said the researchers.

The study appears online in the journal Annals of Neurology.