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.
Correction: January 19, 2002, Saturday An obituary yesterday about Arne H. W. Larsson, a Swedish engineer who in 1958 received the world's first implanted heart pacemaker, misspelled the surname of an inventor of the device. He was Rune Elmquist, not Enquist.