Speech-to-Touch : Hearing With Your Fingers ⋆

Speech-to-Touch : Hearing With Your Fingers

Studies have shown there is a possibility for a speech-to-touch sensory that could improve hearing for those with a hearing impairment.  A recent study published in Restoration Neurology and Neuroscience has uncovered evidence that a very inexpensive, simple device might just have the ability to improve hearing in patients.

Not only could this device help those with a cochlear implant but for those who simply want to have “clearer” hearing in a crowd or to learn a language with better pronunciation. Without any training, this device can immediately provide multi-sensory enhancements.

Amir Amedi, PhD at the Institute for Medical Research Israel-Canada, suggests that even though there have been many advancements in hearing aids and cochlear implants, there are still many challenges for those who suffer from a loss in hearing.  In particular, these patients often struggle with understanding speech in loud surroundings.

A Multi-Sensory World

It is believed that the number of patients with hearing impediments is on the rise and it’s critical that new techniques are developed to improve their hearing.  Dr. Amedi said the world is more multi-sensory and therefore developers must come to terms with the mechanisms underlying multi-sensory perception and integration.

They believe providing relevant information using sense-of-touch can actually help with hearing issues.

Those participating in recent studies involving proof-of-concept believe they will be able to improve speech understanding by manipulating the capacity of the brain to merge information coming from different senses at the same time.

They have created a basic auditory-to-tactile sensory substitution device or  SSD,  that will turn low-frequency speech signals into vibrations dispatched by two fingers.

The team worked with a group of speakers who did not speak English asking them to repeat a series of sentences that were degraded by installing them into a speech-like noise. During the study, the participants could only rely on sentences delivered through audio which was very difficult for them to understand.

But, when combining the degraded speech signal with vibrations delivered on the participants’ fingertips, their understanding became clearer. The vibrations transmitted a specific set of frequencies known as fundamental frequencies that identified the speech signals.

The group’s improvement was measured by a decibel of the ratio between two signals, i.e. dB. The level was 6 dB which was a major increase of 10 dB representing double the anticipated sound.  These results are extremely relevant when compared to earlier sensory substitution device studies in which the effects in behavior were only revealed after subjective training.

Helping the Brain to Interpret Input

Co-author  Tomasz Wolak, PhD Eng, Head of the Bioimaging Research Center, Institute of Physiology and Pathology of Hearing believes hearing through someone’s fingers can significantly help in hearing.

Their approach suggests that multi-sensory stimulation provides the same kind of information through touch in addition to hearing that should be processed in the brain’s spoken language area.  It should then be able to predict the multi-sensory stimulation both with sound and touch.

Katarzyna Ciela, PhD The lead author from the World Hearing Center, Warsaw and Hebrew University of Jerusalem, believes the most fascinating part of the study was the fact that learning with a speech-to-touch sensory does not require any form of training.

The team also believes that this device could be an excellent aid for elderly people who find it very challenging to follow extensive training.  This could well be the first really significant study revealing immediate relevant enhancement of the sensory substitution device, suggesting the brain is more multi-sensory than “common wisdom”.

Bernhard Sabel, PhD Editor-in-Chief of Restorative Neurology and Neuroscience, believes this study is a major step forward to introduce multisensory flexibility of the brain as a contemporary example to maximize the potential of patients to compensate for their sensory loss.

Future plans for the team will be to improve the device and training in order to reach the goal of 10 dB and test the human brain mechanisms using an MRI compatible version of the device for those with average hearing and hearing-impairments.