Sensory Substitution Improves Speech Understanding in Hearing Impaired

Our brains are incredibly adept at adjusting to new challenges, a general concept known as neuroplasticity. Some blind people are known to use echolocation, and now there’s a proof of concept for a similar idea for those that can’t hear well.

A group of Israeli and Polish scientists have developed a “sensory substitution device,” which consists of two touch pads that turn speech into vibrations. The user places a finger over each one and the pads vibrate with a voice that talks over the speakers. The pads are synchronized with the lower frequencies of speech, which we may be using as a timing marker that helps us to understand spoken word.

To evaluate whether the technology could aid in speech comprehension, the researchers had a group of non-native English speakers listen to and repeat different sentences. The sentences that were spoken had a bunch of noisy filters applied to them, making them hard to hear, especially for people that would have trouble hearing in places such as busy restaurants.

Remarkably, the participants were able to understand the spoken sentences much more readily when they were using the sensory substitution device. “Our results carry important implications for further research, as well as possible clinical and practical solutions,” said co-author of the study Tomasz Wolak, PhD Eng, World Hearing Center, Warsaw, Poland. “The ability to ‘hear’ through one’s fingers can significantly help hearing. 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 centers), ultimately then predicting that multisensory stimulations (both sounds and touch) should enhance perception.”