Naming difficulties may be rank ordered along a continuum. Items are rank ordered in terms of their ability to be named, which is correlated with their frequency. This type of picture-naming test is also useful in the examination of children with learning disabilities and the evaluation of brain-injured adults.
The Jarvik-7 heart was developed by American scientist Robert Jarvik and his mentor, Willem Kolff. In 1982, Seattle dentist Dr. Barney Clark was the first person implanted with the Jarvik-7, the first artificial heart intended to last a lifetime.
Early Heart Pacemaker Canadian, John Hopps invented the first cardiac pacemaker. Hopps was trained as an electrical engineer at the University of Manitoba and joined the National Research Council in 1941, where he conducted research on hypothermia.his lead to Hopps' invention of the world's first cardiac pacemaker in 1950. His device was far too large to be implanted inside of the human body. It was an external pacemaker.