8.1 What are the Three Laws of Tomatis?

Through work with singers, Tomatis established that when certain frequencies are missing from the hearing, they will automatically be missing from the voice.

He found that by retraining the ear to hear certain sounds, they would spontaneously re-appear in the vocal range.

By retraining the ear consistently with an ongoing program of sound therapy, he was able to make a permanent correction of frequency restoration.

Through Tomatis’ work with singers, the moment where a light went on for him, was his first key discovery that “the voice contains only those sounds that the ear can hear.”

This became known as “the First Law of Tomatis”, after it was tested and verified at the Sorbonne University in Paris.

Tomatis had established in his clinic that if a subject emits a vowel into a microphone, and the sound is then passed through a series of filters which would suppress particular frequency bands before being fed back to the subjects ears, those sounds that had been removed from the sound signal were then also emitted from the spectrum of vowels being produced by the person’s voice. Similarly, he found that for those who presented with a hearing loss, when he measured their voices they proved to be deficient in the same harmonics that were missing from their hearing.

Through these discoveries Tomatis developed his “Electronic Ear,” the device that is the keystone of Tomatis Sound Therapy filtering. After treating his subjects through a series of amplifiers and filters, Tomatis automated this process with the Electronic Ear in order to streamline the procedure.

His aim was to bring about a permanent change in the listener’s hearing, which would translate into a permanent change to the voice. He found that if they were treated soon enough, before hearing loss had become permanent, he was able to restore lost frequencies to the voice. However, the result seemed to only be temporary.

The next question Tomatis explored was how could this change be made permanent?

Through further experimentation, he found that with a regular course of treatment using the Electronic Ear, the lost frequencies were restored permanently to the voice. In this stage of experimentation, Tomatis found that he could recondition the ear by having the person listen to their own voice conditioned to contain a greater frequency range and quality. He introduced greater audio-vocal control using a microphone so that the singers were hearing their own voice directly modified through the filters he had set up. After a certain period of treatment in this manner, he found that the changes were maintained.

Tomatis coined the term “audio-phonology” which means to hear oneself speak, and listen to oneself. In Tomatis’ view, the ear is the main organ of control for our language—all of our outwardly directed information.

Tomatis said “a good utterance demands not only a good auditory receptivity but a good self listening”. He suggested that self listening was the key to  being a good singer, and that the greater self control a person had over their voice, the better quality they could produce.

Tomatis revealed to us the neural circuitry of our audio-vocal linkages. Because the muscles of hearing and speech are innervated by the same cranial nerves, the integration of this system can be seen in our physiology.

The cranial nerves innervating this system are:

• Trigeminal CN V
• Facial CN VII
• Glossopharyngeal CN IX
• Vagus CN X

The Trigeminal Nerve delivers the following actions:

• Motor control –Jaw movement
• Links between face, jaw and inner ear
• Tensor Tympani (Hammer muscle)
• Eustachian tube muscles
• Sensory feedback
• Facial control and sensory awareness

The Facial nerve delivers the following actions:

• Innervates the stapedius muscle (stirrup muscle)
• Control of facial expression
• Link between face and inner ear
• Shares filaments with auditory nerve in outer ear canal

The Glossopharyngeal nerve delivers the following actions:

• Motor control of the voice, tongue and soft palate
• Linking the ear drum to the throat
• Motor control of pharynx and larynx

Improved high frequency perception enhances vocal tone.

Tomatis taught us about the key role of the two middle ear muscles in our audio vocal control. He showed how by retraining these muscles we can become an active listener, able to scan the auditory field and focus intentionally on sound. Thus, his Sound Therapy program trains the person to be an active listener able to monitor their own voice at a sophisticated level and to scan and select the sounds of interested from a complex field of sound.