. >> near san diego, california, katie walker is putting her latest tool are to effect.personally for herself on the field. >> if the attachment pops off. the bat attachment the bat handle goes right inside of here. so it's supposed to after i swing after i pop it through i can pop it right off and start running. >> and then rotate around. cool. >> for upper limb amputees like jason and katie, gone are the days of hook lever arms. alongside occupational therapists to design custom made prosthetics for patients' dreams. >> the opportunity osee a patient, see what they need, instead of just, we can be really creative. >> thanks to myo credit technical are advances, one of the most sophisticated prosthetics on the market, the ilem revolution, the ability to rotate the thumb and there's even an app for that prospect. you. >> what are these electrodes measuring? >> these electrodes are sensing your muscle contracting. you're now bionic. >> and so powerful, i should be able to control this robotic hand by moving my muscles. >> you see that spike? the hand is operating. i want