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Tomatis, Autism and Sensory Integration

.......Tomatis Topics

T he Leading Ear

" AND THE GOOD EAR WILL LISTEN TO WISDOM"

Eccl. iii, 29

Tomatis came up with the concept of the leading ear in the 1950's shortly after his discovery of the audio-vocal relationship known as the Tomatis Effect. From his work with opera singers Tomatis found "that the voice can only reproduce what the ear can hear". For his effort, the Academy of Science and Medicine at the Sourbonne recognized his findings and named them the "Tomatis Effect" He found this by comparing the audiograms and the spectrographs of voices of singers and factory workers exposed to noise. What he found was that there were similar distortions in both functions.

It was during these experiments while interfering with the singer's hearing in order to better study the parallels between displacements of the auditory and vocal scotoma's, he discovered the response reactions obtained from the ears were not identical. To look at this further he set the singers up at a microphone that would feed the singers voice back to them via two headphones, one the left ear and one to the right ear. The attenuater allowed the subject to hear themselves either through the right ear, the left ear or both ears by changing the balance level. For this experiment they took well known singers, known for their voice, and known for the familiarity with the piece, and known for their endurance. One of the singers they used had just finished 400 performances of the same work and every night he had done one or two encores of the same aria he was to sing during the experiment. During the experiment all the attempts were recorded.

The following findings were observed:

Listening with the ear's balanced (we'll call that balance 10) the voice was the same as is the singer was singing without any apparatus. Neither the singer nor others noted any change Suppressing the left ear, and leaving the right alone in the controlling position, there was only slight modification. To the very trained ear, the sounds seemed lighter, more ethereal, more modulated, more precise, more distinct and the singer felt greater fluency but not necessarily observable to the general public.

When the reversed the control and placed the left ear in control and eliminated the right, the fluency vanished and all the professional qualities acquired by the singer broke down. The voice became heavy, coarse, less colorful and off pitch. Worst of all, the rhythm slowed down considerably. The destruction of the rhythm is beyond the reach of the singer's will. In some instances it would take the person double the time normally to perform the musical phrase. He could become aware of it, if someone beats time for him, but he is incapable of following the tempo. The blockage is not limited to singing. During the experiment, the subject movements became slower, more robotic like and a diminished capacity for voluntary control.

The same results were obtained when the ears were saturated with sound vs. blocking the sound as can be done with masking on an audiometer. So it wasn't lack of sound it was the cutting of control of the ear. Tomatis found the same phenomenon with the spoken voice. This time he did the same experiments with actors. With the left ear suppressed, (the right ear leading) the voice became lighter, more timbre and higher pitched.

With the right ear eliminated, ( the left ear leading) the voice was flat, without tone or timbre and badly produced, it became filled with hesitations, with "ah's" and more prolonged. Even full blown stuttering The conclusions that Tomatis drew were that there is a preferential ear, disignated to execute the more special and more precise control functions. He call this the Leading ear and using the analogy of the leading eye, it was the one that took aim in that the speaker takes aim at the sounds he emits.

T HE LEADING EAR AND STUTTERING

As Tomatis continued his research he found that by establishing auto-control by a single ear in a voice that was either disorganized or not yet organized, always produced an improvement, no matter which ear was chosen. Remember his last research was on individuals with good ears, singers and actors. He determined that the coexistence of two auditory receivers can be a troublesome factor. The next area that Tomatis looked at was the role of the leading ear in stuttering. This was from his finding that when he masked the leading ear some people with normal phonation they actually started to stutter. This result was not found in all subjects however.

He started with the premise the "It was the right ear that controlled speech and stuttering was bound up with the loss of this controlling ear. This lead him to theories of laterality and control of listening that was relevant to stutters but applicable to many other listening disorders. At the same time he became aware of research being done in the United States at Georgetown University by John Lee and John Black. They found by delaying the feedback that someone received from their own voice, by speaking into a microphone, taping the voice, and delaying the feedback, they would elicit stuttering and that this stuttering occurred when the delay reached a specific threshold. Tomatis duplicated this experiment by using a long tube, making holes that corresponded to a one tenth of a second delay. Lee and Black had found that articulation difficulties occurred between one-tenth and two-tenth of a second. Tomatis found very similar results.

He postulated that poor lateralization in contrast with good lateralization, introduces an element of delay caused by an extra step in the transfer of information. Instead of the faster passage from the right ear to the speech centers in the left hemisphere. information from the left ear went to the right hemisphere and then back to the left hemisphere. This transfer can take place between .05 seconds and .4 seconds but varies with the individual. So some people can lose their directing ear and still not stutter. Stuttering appears when it occurs within .1 seconds and .2 seconds with a peek at .15 seconds. Tomatis also found that the average duration of physiological delay varied according to the language of origin. .15 for the French and .2 for English. Therefore many multilingual speaker can be fluent in English while stutter in French. In 1950 Tomatis treated 70 stutters by training them for right ear dominance. He had very good success with some responding with only a few sessions and others requiring up to a years treatment. All maintained their progress in follow-up evaluations. He would have thought he had the whole answer in the hypothesis of the directing right ear if it wasn't for two clients who failed to respond to treatment. ?the color of their hair and skin The only difference he could find was in the color of their hair and skin. The unsuccessful clients had blond hair and blue eyes where as the successful clients were all darker! He pondered this wondering if it was a particular sensitivity in play. It was not an auditory sensitivity as he hadn't recorded it on the audiogram, so he contemplated a skin sensitivity. Tomatis has always contemplated the relationship between the skin and the ear so this wasn't a funny place for him to look. He contends that the skin is a piece of undifferentiated ear. In Vers L'ecout Humaine which hasn't been translated he contends that phylogenticaly the ear preceded the nervous system and further that he sensory cells found in the skin (Meissner's Pacinian, Krause, Merkel's) are differentiated cells of corti and the evolution of the sensory cells of corti towards cutaneous hair cells of the skin support the hypothesis the we listen with our skin.

So he created a type of cutaneous audiogram, which he called a dermogram. He found that with the darker skinned individuals that they registered sounds at 10-15 decibels, while the two fair skinned individuals registered sounds at 80-100 decibels. When we speak, we also have to listen to ourselves. This is part of the audio-vocal feedback loop that is controlled by the directing ear. The ear regulates the intensity, volume, duration, however it doesn't control the flow. When we talk an acoustic stream comes out of our bodies in successive waves, shaped in its form and volume by our articulation and poured over us. Cutaneous sensitivity and the quality of phonatory control are in constant relation to one another. So if the skin lacks sensitivity the whole process of audio-vocal control is endangered.

If you isolate the body, by putting the head in a baffle for example, you immediately disturb the whole regulation. The most persistent stutters were particularly deprived of the dermal control mechanism. The treatment of these kinds of stutters required helping them to learn to sense the flow of sound over their skin. As Tomatis more eloquently put it "the person must learn to use his body like a musical instrument.... a cutaneous keyboard. He also made another interesting observation about these "recalcitrant stutters". He didn't feel that it was that they couldn't hear the sounds but rather that they couldn't defend against them and would therefor shut down until they were overwhelmed and presented with a negative reaction. "The ear and by extension the skin had an all or nothing perception. They experience the sound as an attack and the speech flow pouring over their bodies caused stress" (109CE) Where on the other hand people with sensitivity in the 5-10db range were able to adapt and defend against sound better. They had a bettor control mechanism. They could regulate between their skin and their ear in a more adaptive fashion. He described the reaction in the fair skinned people "as a timidity which to be strictly accurate, has no relationship to a person's emotional nature." Sound like anything familiar? Now to be clear, Tomatis isn't saying that fair skinned people who stutter have more difficulty listening than dark skinned people, I believe it was an observation that lead him to look at the role of the skin in the machismo to control speech.

T omatis finally came to the belief that ultimately the stutterer does not hear or listen to themselves, and this is because he is incapable of auditory awareness on the level of bone conduction. This doesn't mean that the individual cannot hear through bone conduction, it more that they don't process through bone conduction. When we speak the sound comes out, with the higher sounds thrown out in a straight line, and lower sounds spread out everywhere. (that's one of the reasons why our voice sounds funny in a tape recorder).

At the same time the skill vibrates and transmits sound information directly in the ear and down the spinal column directly into the whole body. Great singers control their voices through bone conduction. Tomatis found in stutters and this is especially true for autistic children that there was a lack of harmony between bone and air conduction, with the latter (bone conduction), always being more sensitive.