Amongst the challenges faced by the deaf is what's known as the "cocktail party effect," in which they have difficulty discerning one speaker's voice from others in crowded, noisy environments. A new device could help, however – by buzzing two of their fingers. Led by The Hebrew University of Jerusalem's Dr Amir Amedi, an international research team started with 12 test subjects (both male and female), aged an average of 29 years old. All of them spoke English, although not as their first language, and none of them had any reported hearing problems.
The volunteers were tasked with listening to 25 groups of 10 short, simple sentences, all of which were spoken in English in a male voice. Distracting, background-conversation-like noise was added to the audio. When the test subjects initially listened to the sentences using headphones only, they found it quite difficult to understand what the speaker was saying. Their understanding improved considerably, however, when they listened while also holding their index and middle fingers against an inexpensive tactile feedback device.
Known as a Vibrating Auditory Stimulator, that device converted low-frequency speech audio signals into vibrations. The scientists believe that it helped the participants by allowing them to use two of their senses – hearing and touch – to interpret what was being said. All told, it produced a 6-decibel improvement in perceived loudness. For reference, 10 db represents a doubling of loudness.
"Our approach suggests that multisensory stimulations providing the same type of information (in this case spoken language conveyed through touch in addition to hearing) should be processed in the same brain region (in this case spoken language centres), ultimately then predicting that multisensory stimulations (both sounds and touch) should enhance perception."