The phenomenon the so-called choral effect was first identified in the 1950s. The device is called SpeechEasy. It is not available in the UK and is not funded by the National Health Service. Mr Lieckfeldt said that this device though it works quite well for a lot of people who stammer, it doesn't work for all of them.
She also said that more research is to be done to understand the mechanism and working of the device. A spokesman for SpeechEasy said several thousand people in the USA had had the devices fitted and experiencing a new life.