The most important diagram for people who stutter

How tension and stress impact on stuttering

I hope I caught your attention with that heading, because this diagram really is of crucial importance if you want to understand how stress and tension impact on stuttering. This diagram is the brainchild of Dr Martin F Schwartz and appeared in his second book, Stop Stuttering (1986), co-written with Dr Grady L Carter. I am sure that, once you understand its implications, you will see stuttering in a new light.

Let's first look at the lower horizontal broken line, representing "base-level tension". What is base-level tension? It really is your current stress level. That means that it is the total of all the various tensions affecting you at a particular moment. We don't live in a single-tension environment; lots of various tensions impact on us, such as whether you've had a good night's sleep (if not, it could cause physical tension), whether you're feeling anxious because of an upcoming exam or presentation (emotional tension), whether you are talking to a stranger (uncertainty tension) or an authority figure such as a police officer, employer, teacher, lecturer etc. (authority figure tension). Even the weather can influence stress levels.

The total of all these tensions is "base-level tension". Dr Schwartz defines the term as the total tension on the vocal cords when a person is not speaking or does not intend to speak. For the sake of simplicity, however, let's just regard this as the "stress level". Note that this stress level is not static; it fluctuates continually, either rising or falling depending on the number of and the intensity of the various tensions influencing us. And this stress level can rise very, very quickly indeed.

The fear is learned 

The second broken horizontal line of note in our diagram, the upper line, is "John's threshold". John is a person who occasionally stutters, and he has a stuttering threshold. If this line is crossed, he will stutter.

The third line of interest is the unbroken curved line representing John in the process of trying to say his name. This line reflects John's "speech tension". Speech tension is the muscular tension required for speech - because speaking requires that the mouth, tongue, lips, vocal folds etc. move very quickly into certain positions. All this localised activity not only requires tension, but also generates tension - which is picked up by the stutterer's tension-sensitive vocal cords. If this speech tension remains below John's threshold, he will not stutter; but if it should rise, it may exceed the threshold level so that stuttering results.

In the diagram, John has to say his name. For him this is a stressful thing to do - he knows that he usually stutters when he has to say his name; it is a feared word for him. This fear is learned (conditioned); it's the result of the many times in the past when he stuttered on his name. Because of the fear and the conditioning his speech tension quickly rises, forced upward by his rising stress level (the bottom line, i.e. base-level tension), so that when he has to say "John", he exceeds his threshold and stutters.

The margin of fluency

You will note that there is a margin or space between the threshold and the base-level tension ("stress level"). This is our margin of fluency, and its depth depends on how low or how high the base-level tension is. So if our stress is very low, for instance when on holiday, the margin of fluency will be large, and there won't be much stuttering.

But if the stress level is high, the margin of fluency is narrow so that the "speech tension" does not have much room to move in and will easily and often exceed the threshold. 

Usually the stress level (base-level tension) is below the threshold, so that the person who stutters has a degree of fluency. However, people differ - some people have very elevated base-level tension, with the result that they may stutter on most or all words.

Implications

This important diagram explains why so many people who stutter have "good" and "bad" days of stuttering - on "good" days, their stress levels are way down. On "bad" days their stress levels are close to or on or even above their threshold.

It also shows why it is so crucial for people who stutter to work on keeping their stress levels as low as possible, in order to avoid crossing their threshold. In addition it may be possible to increase one's threshold so that it is not so easily reached.

The diagram also indicates why "soft contact" speech, also known as "low energy speech", where a person speaks softly, slowly and with the minimum movement of the speaking organs such as the lips and tongue, can be very helpful. With this type of speech, "speech tension" is kept to a minimum so that it does not reach the threshold easily. Fluency techniques such as the Passive Airflow Technique do the same thing - they reduce speech tension. However such techniques will be difficult to apply if base-level tension is excessively high. Such techniques should be used together with stress management in order to be effective.

I am sure that you will agree that this diagram makes a lot of sense in explaining a great deal about stuttering and stress. Becoming aware of things such as "stuttering threshold", "speech tension", "margin of fluency" and base-level tension helps in managing the disorder better and perhaps even in working toward improved fluency, through efforts to reduce stress and speech tension levels and increase the threshold level.