Can Deaf People Speak?
This is a question that almost everyone who has a deaf family member has thought of. Most people who are deaf are also mute. Being deaf and mute increases the disability significantly. Not only are these people not able to listen, they are also not able to speak. Consequently, they find it difficult to be integrated into society. People who are deaf have the ability to speak. The reason they are unable to speak is because the part of the brain that controls speech (Broca’s speech area) needs inputs from the part of the brain that helps people listen (auditory cortex). Unfortunately, people who are deaf get no input signals into the auditory cortex. Simply put, people who are mute because of deafness can be made to develop speech if we find a way to stimulate their speech area.
How do normal people speak?
Sounds are carried as wave forms to the ear. In the inner ear, the waves are converted into electrical signals. These electrical signals are then carried to the brain via a complicated system of nerve networks. Sound is processed in a part of the brain known as the auditory cortex. The brain is an interconnected network wherein most parts of the brain connect and are networked to almost all the other parts of the brain. The auditory part of the brain sends signals to the speaking part of the brain. The speech cortex (Broca’s area), then sends signals to the mouth, the tongue, the lips and other peripheral parts of the body that are associated with speaking. When we speak, we also hear ourselves. This hearing of oneself helps finetune language and pronunciation.
How can a deaf person develop speech?
The most important aspect of developing speech is to improve hearing. It is absolutely vital that whatever hearing is retained needs to be amplified using hearing aids, cochlear implants or other devices. However, if one is profoundly deaf and has had no hearing until the age of 3 years, the brain and its pathways re-wire themselves. The auditory cortex gets taken over by the visual cortex(part of the brain which helps us to see). The wires (nerve pathways) that carry signals to the brain stop functioning. So, in this group of profoundly deaf people even if hearing is restored after 5 years (in many cases after 3 years), the outcomes in terms of developing meaningful speech are limited.
Other interventions that help develop speech
It is clear that for speech to develop, we need to find a way to stimulate the Speech cortex (Broca’s area). If one has reached an age where cochlear implants cannot help restore speech, the following interventions may be tried.
- Speech Therapy: Many speech therapists who are well trained can help a deaf person develop some speech. The results may be limited but with perseverence and good inputs from a speech therapist and a parent, some meaningful speech may develop.
- Stimulate the Broca’s area via other sensory areas: Since the brain is well networked and interlinked, we may be able to stimulate the Brocas area by giving signals to some other sensory part of the brain. In seesoundlive, we stimulate the visual cortex. It is anticipated that the visual cortex will now communicate with Broca’s area and will stimulate the Broca’s area and hence the deaf person will develop speech.