Biology 202
2001 Second Web Report
On Serendip

"Stuttering is something the stutterer does, not something he has, because of something he is." --Wendell Johnson

Can you imagine not being able to introduce yourself without struggling to pronounce your own name? What would your life be like if you had to battle every time you said "hello"? How would you feel if a mob of security guards surrounded you at Wal-Mart because an employee had mistaken you for being mentally ill ((1))?

These are just a few scenarios that 42-year-old Kurt Salierno, a carpenter and minister from Atlanta, encounters everyday. Salierno has a stuttering disorder, which more than 3 million people in the United States and 55 million people around the world struggle with daily. Salierno describes his problem as similar to being trapped in a glass capsule; "I can see out, but there's no way to get out" ((1)). Salierno's feelings and views about what he experiences raises some interesting questions. What is reality like for a person with a stuttering disorder? Is the "I" that is trapped inside the capsule representative of the self that he cannot express due to his disorder? Internally, Salierno is conscious of the words, which he wishes to express. However, Salierno is seldom able to produce these words externally. Does a stutterer create his or her own reality within his or her mind? To the stutterer, does independent experience become reality? With reference to the philosophical thought experiment about the tree falling in a forest, does a stutterer make a sound if no one can hear him or her make that sound?

Stuttering is a neurological disorder of communication, from which the normal flow of speech is disrupted by repetitions (neu-neu-neuro), prolongations (biiiii-ol-ooogy), or abnormal stoppages (no sound) of sounds and syllables. Rapid eye blinking, tremors of the lips and/or jaw, or other struggle behaviors of the face or upper body may accompany speech disruptions ((3)). Why does stuttering worsen in situations that involve speaking before a group of people or talking on the phone, whereas fluency of speech improves in situations such as whispering, acting, talking to pets, speaking alone, or singing ((1))? In ancient times, physicians believed that the stutterer's tongue was either too long or too short, too wet or too dry. Therefore, practitioners from the mid-1800s tried surgical remedies such as drilling holes into the skull or cutting pieces of the tongue out to eliminate stuttering ((1) ).

Specific causes for stuttering are yet unknown. However, extensive research is currently in progress in search for answers. Researchers are certain that stuttering is not the result of psychologic or emotional problems, learned behavior, tension in the larynx, or other external speech articulators ((4)). Rather, stress and emotional difficulties may arise from stuttering. For example, a neurological mishap may cause a person to stutter on a word for the first time. Later, the stutterer might remember the embarrassing experience, become nervous, and be more likely to stumble over the word again. The memory of stuttering on the particular word locks in. In addition, all the associated feelings and emotions are locked in ((1))

Since the hypothesis is that memory locks in, it is possible that the I-function plays a role when first establishing the experience of the stuttered word for later occurrences. Eventually the I-function is not needed in order for the word to be stuttered, since the stutterer does not need to be consciously aware of stuttering, as he or she did at first when the involvement of the I-function is necessary.

Scientists have argued about the causes of stuttering for a long time. Some argue that stuttering arises from hearing deficiencies. Others believe that oddities in the areas of the brain, which govern the motor functions of speech cause stuttering. Still others argue that the left side of the brain, the side of the brain that commands language, fails to develop properly. In fact, all of these arguments are valid ((2)).

The most recent studies show that genetics and brain function are crucial factors in the development and persistence of stuttering. The likelihood that a child will begin to stutter and the likelihood of continuing depend a lot on the family tree and the child's gender. The studies show that one gene, combined with the smaller effect from a small group of other genes, has a large influence on the susceptibility to stuttering. However, this does not mean that a single stuttering gene exists. Stuttering is more common in males than females with a ratio of about 4 to 1 ((5)). This suggests that stuttering is inherited from the mother, since the male's single X chromosome can only come from the mother.

About five in every one hundred children begin to stutter at some point, most before age five. Roughly four of those five will stop within a few years. The common belief, however, has been that the family link came not from genes but from family attitudes. It has been thought that parents with a family history of stuttering tend to overreact to a child's normal speech repetitions. These overreactions tend to lead to real stuttering ((5)).

Positron-emission tomographic (PET) imaging studies of brain blood flow have revealed striking differences in the brain physiology of stutterers and non-stutterers. Most active areas are assumed to have high blood flow. It turns out that stutterers may be using the wrong side of their brains when they speak. The right hemisphere seems to be interrupted or interfering with the left hemisphere ((1)). PET scans of non-stutterers show both hemispheres lighting up when they speak, with more activity on the left. More activation of the left hemisphere occurs since the left side of the brain commands language. By contrast, a stutterer has more hot spots on the right, possibly interfering with what should be left-sided speech production. Interestingly, stutterers' scans start to resemble those of non-stutterers during moments of fluency of speech. When stutterers imagined that they are stuttering, the strange brain patterns emerge even though the stutterer does not actually move his or her mouth or produce sound ((1)). When stutterers imagine the act of stuttering, they recreate the emotions and feelings they experience from stuttering. The memory of the emotions associated with stuttering lock in and causes similar brain patterns of the actual situation of stuttering. Is the imagined experience of stuttering perceived as reality to the stutterer?

In stutterers, a region of the brain that processes hearing is deficient while they are speaking. Although active in fluent speakers, this region is nearly silent in stutterers. This finding suggests that the stutterer is tuning oneself out as he is trying to speak, which means that he or she blocks out the disrupted speech ((1)). It is possible that an inhibitory mechanism exists to prevent fluency in a stutterer. Many hypotheses arose concerning what causes stuttering. However, what allows fluency of speech when a stutterer whispers, acts, talks to pets, speaks alone, or sings? No answer currently exists. However, the I-function probably plays a role. In order to sing, for example, one must concentrate intently on intonation for the production of sound. Since, the I-function is activated only when one is consciously aware of a situation, it is possible that fluency occurs with the activation of the I-function. On more scientific terms, concentration involves more thinking causing activation of the brain. More areas of the brain, both the right and left hemispheres, become activated allowing the fluency of speech.

The issues presented do not have definite answers. However, known facts, such as the left hemisphere of the brain commanding communication, help researchers question and ponder about what causes and does not cause stuttering. I am extremely enlightened by the fact that stuttering stops during some situations, especially singing. This is something I hope to continue to disclose.

WWW Sources

1)Anatomy of a Stutter, Brain, genetic studies shed light on stuttering

2) Brain Regions Stutter to a Halt

3)National Institute of Health -Stuttering

4)Neuropatterning for Stutterers

5) Stuttering Appears to Have Strong Link to Family Genes


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