An article from The Psychologist has just been made available on the ‘anarchic hand syndrome’ – the brain injury-related condition where the hand performs actions against a person’s will.
One evening we took our patient, Mrs GP, to dinner with her family. We were discussing the implication of her medical condition for her and her relatives, when, out of the blue and much to her dismay, her left hand took some leftover fish-bones and put them into her mouth (Della Sala et al., 1994). A little later, while she was begging it not to embarrass her any more, her mischievous hand grabbed the ice-cream that her brother was licking. Her right hand immediately intervened to put things in place and as a result of the fighting the dessert dropped on the floor. She apologised profusely for this behaviour that she attributed to her hand’s disobedience. Indeed she claimed that her hand had a mind of its own and often did whatever ‘pleased it’. This condition is known as anarchic hand: people experience a conflict between their declared will and the action of one of their hands.
The article is by neurologist Sergio Della Sala who has been researching anarchic hand syndrome for many years.
It discusses the possible causes of the condition, and what these disruptions to human ‘free will’ tell us about how the brain generates the conscious control of actions.
Link to article.
Mind Hacks 
What is the condition, when a person is not aware that their is something in their hand but when asked, they can feel what it is and identify what the object is?
The hand does not make any involuntary actions on its own.
The problems seems to be spacial awareness of the left hand only.