*3.2. Overcoming Paralysis*

Philip Kennedy developed an operable system which allowed an individual with paralysis to spell words by modulating their brain activity. Kennedy's device used two simple electrodes: the first was implanted in an intact motor cortical region and was used to move a cursor among a group of letters. The second was implanted in a different motor region and was used to indicate that a selection had been made [21].

As the patient thought about moving their fingers these signals were translated into signals to move and stop a computer cursor. The patient could actually see where the cursor was on a large computer screen. Hence they could decide as to when to stop thinking about moving. In this way words could be spelt out letter by letter but also heating and lighting could be controlled quite simply [22].

A different approach was taken by Todd Kuiken whereby nerves normally connected to the pectoralis muscles were employed in a process termed targeted reinnervation. In this procedure, nerves originally connected to arm muscles were reconnected to the pectoralis muscles. As the individual thought about moving their hand and arm so the muscles on the top of their chest flexed instead. External electrodes monitor these movements and send resultant signals to a prosthetic arm worn by the patient. Effectively the person's nervous system is rewired via the pectoralis muscles [23].

The first beneficiary of this technique was Jesse Sullivan, hailed in the media as the world's first 'Bionic Man', who lost both of his arms as a result of an accident he sustained during his work as a high-power electrical lineman. His arms were replaced with robotic prosthetics that he was able to control merely by thinking about using his original arms in the normal way.
