The noise is essentially the sound of a restaurant full of patrons, but without the clattering silverware and clinking glasses.

'They had an easier time getting louder when I had the noise in the room,' she said. 'Ordinarily, when I asked them to be twice as loud they would say they couldn't. They couldn't speak 10 decibels louder, but when I turned on the babble noise, they spoke over 10 decibels louder.'

The background sound elicits a well-known phenomenon called the Lombard effect, a reflex in which people automatically speak louder in the presence of background sound.

Huber created a new electronic technology using this principle. The voice-activated device automatically plays the background babble when the person begins to speak, said a Purdue release.

A sensor placed on the neck detects that the person has begun to speak and tells the device to play the babble through an earpiece worn by the patient.