The scores suggested that the nascent capacity to perceive pitch was there, waiting to be exploited with better software and better training. For example, Rubinstein's lab has been experimenting with an algorithm using a phenomenon called stochastic resonance to improve music perception.
So there was a good reason for the melody test to be hard, I realized. It was not an impossible test for implant users, but merely a very difficult test. It was a simple, easy to use, and reliable test that let researchers measure the performance of new algorithms objectively. (A paper giving data on a larger group of subjects and demonstrating test-retest reliability is currently in review, Rubinstein says.)
The test also lets subjects measure progress over time. If in 10 years scores have doubled, that will mean that implant users really are hearing the basic elements of music better.
The test would also make it easier for researchers to analyze the performance of "superlisteners" like John Redden so that, ultimately, they can develop new software to let other deaf people hear music better.
Michael Chorost covers implanted technologies for Technology Review. His book, Rebuilt: How Becoming Part Computer Made Me More Human, came out in 2005.