original author: Cindy S. Spillers
|Fluency||Dysfleuncy||Distinguishing stuttering from normal||Secondary behaviors||Covert features||Physiological features||Conclusion|
Stuttering is considered a disorder of fluency in that the individual has difficulty moving smoothly from one sound to the next. Before understanding what a fluency disorder is, it helps to understand something about fluency.
What is fluency?
Fluency is one of those things that we all intuitively recognize yet struggle to define with words. The word "fluency" connotes facility of speech and language performance. Fluent people are so skilled at talking that they don't need to put much thought or energy into the act of talking. Instead, they put their thought and energy into the content of their message. Think of your early experiences in learning to speak a second language. You probably had to put a lot of energy and attention into choosing your words, making sure you had the correct form of the word, making sure that you had the words in the proper order, using the correct pronunciation, and using the correct inflection patterns to make sure your message came out clearly to native speakers of that language. You probably weren't considered a very fluent speaker of that language at that point.
Fluent speech has at least three dimensions or components that converge to give listeners the impression of fluency. First, fluent speech is continuous or smooth. It flows along without hesitation or without stopping unexpectedly. Fluent speakers seem to utter long messages with ease and grace. Various behaviors can disrupt the smooth flow of a message. Some common disrupters to fluency include unfilled pauses, filled pauses (um, uh), revisions, unfinished sentences, and repeating syllables, words, or groups of words. These behaviors also constitute what we call dysfluencies in speech. When fluency is disrupted by any of these behaviors, the flow of information or the flow of the message stops, not necessarily the flow of speech. When the flow of a message gets interrupted and that message does not come out at an expected rate, we may perceive that person's speech as dysfluent.
This brings us to the second dimension of fluency, rate. We have been socialized to expect information to flow at a certain rate and we have an intuitive sense of what that rate is. For American English speakers, we prefer information to flow between 150-170 words per minute (wpm). This number represents the rate of information flow. Some words are longer than others or have more sounds in them so we make tiny adjustments to our rate of speaking in order to maintain this constant rate of information flow. We can measure rate of speaking in syllables per second (sps). Most American English speakers speak at a rate of 5-7 syllables per second. We speed up our rate of speaking on longer words with more syllables or sounds in them and slow down our rate on short words of one syllable with fewer sounds in them. For example, the two words "hippopotamus" and "cat" will both take about the same amount of time to say, although "hippopotamus" has more syllables and more sounds than "cat." We will actually articulate the sounds and syllables faster in "hippopotamus" so that it requires the same over all amount of time to say as does "cat."
The third aspect of fluency that we have an intuitive sense about is the effort of the speaker. Fluent speech looks easy and effortless in two ways. First, fluent speakers seem to put very little muscular or physical effort into the act of talking. Talking requires very little physical energy from us compared to the amount of energy required to do other common things like walking and writing. Second, fluent speakers seem to put very little mental effort into the act of talking. Rarely do we need to think much about what we do when we talk and how our mouths move. We put most of our mental energy into composing our message and listening to our partner's message.
What is dysfluency?
Based on the above information about fluency, we can explain dysfluency as anything that disrupts the forward flow of the message, slows the message down, and/or requires more mental or physical effort on the part of the speaker. Some common disruptions to fluency were mentioned before and are considered dysfluencies (unfilled pauses, filled pauses (um, uh), revisions, unfinished sentences, and repeating syllables, words, or groups of words). Virtually all people have dysfluencies in their speech. We all pause, say "um," repeat words or phrases, and revise our message. Most of the time, these dysfluencies go unnoticed and don't really interfere with communication. Likewise, most of the time these dysfluencies, in and of themselves, do not constitute "stuttering" or a real communication disorder. When does the presence of these fluency disrupters cross the line and become something that we would consider abnormal and a disorder?
Distinguishing stuttering from normal dysfluency
On the surface, stuttering differs from normal dysfluency in the type of behavior, amount of behavior, quality of behavior, and reason for behavior. People who stutter use different kinds of dysfluencies than normal speakers, use a greater amount of dysfluencies, have different qualitative characteristics to their dysfluencies, and use dysfluencies for different reasons than people who do not stutter.
Certain dysfluencies are considered more characteristic of stuttering than of normal speech and these dysfluencies are often referred to as the core stuttering behaviors. The three classic core stuttering behaviors are part word repetitions, prolongations, and blocks. Part word repetitions are just that: the person repeats a syllable or small part of a word rather than repeating the entire word (e.g. wa-wa-water). Prolongations involve holding on to a sound, such as "sssssalt." Prolongations have audible sound, as opposed to blocks, which are usually inaudible. Blocks are sometimes called "silent posturing" because during the block when no sound comes out, the person usually has their mouth set for the sound that they want to say. All three of these behaviors are considered "intra-morphic" or within word. They disrupt the integrity of a word. Although part word repetitions, prolongations and blocks are associated with stuttering, people who don't stutter sometimes use these behaviors and people who stutter use other dysfluencies besides these. The presence of these behaviors, alone, does not constitute stuttering.
The amount of dysfluent behavior can contribute to differentiating between normal dysfluency and stuttering. People who stutter tend to have a greater amount of dysfluency in their speech than people who don't stutter, particularly the intra-morphic behaviors. A common rule of thumb that clinicians use to help identify early stuttering in young children is more than 10 dysfluencies per 100 words and more than 3 stuttering-like dysfluencies (core behaviors) per 100 words. The amount of dysfluent behavior, by itself, does not accurately distinguish between normal dysfluency and stuttering, however. Some people who stutter have very few outward dysfluencies in their speech and a counting of moments and types of dysfluency would fall into the normal range. Therefore, we must look at some qualitative features of the dysfluencies.
Qualitative features of dysfluencies relate to the effort domain of fluency. People who stutter give the impression that they need to put more physical and mental effort into the act of talking than is common. Tension and struggle are two primary indicators of excess physical effort. People who stutter often have excess tension in their tongues, lips, jaws, and throats. This tension can spread to the head and neck region and other parts of the face. In addition, people who stutter sometimes show signs that they are struggling to get their words out. They may push their tongues to the roofs of their mouths and push the air and sound out with a lot of force. The pitch or volume of their voices might rise as they are struggling to get out a stuck word. When repeating a syllable they may use the schwa vowel instead of the real vowel in the word, for example, "puh-puh-puh-paper" instead of "pa-pa-pa-paper." In addition, they may repeat a syllable or word 10 -15 times rather than 1 or 2 times. The rhythm of the repetitions may be jerky and uneven rather than even and rhythmic. Even these qualitative features of dysfluencies might not give us an accurate way to differentiate between normal dysfluency and stuttering because not all people who stutter show pronounced struggle and tension. We need to look at the reasons behind those dysfluent moments.
When most of us non-stutterers have dysfluencies, those disruptions happen for one of two general reasons. First, we may be trying to buy some time from our listener. We need to buy time when we don't quite have our message together or when we can't find the word that we want to use. Second, we may have disruptions to our message when we have to repair a mistake that we made. We make such repairs when a word comes out wrong (slips of the tongue) or when we decide to change our message at the last minute. Not so with stuttering. The person who stutters knows what they want to say, they have their message together and have the word ready. Stuttering dysfluencies happen because something has gone temporarily awry with the connection between the brain and the speech muscles. The stutterer can not move from one sound to the next freely and smoothly. These dysfluencies are involuntary and do not serve a conversational purpose in the way that normal dyslfuencies do.
Other communication disorders also involve difficulty moving smoothly and freely from one sound to the next, most notable apraxia. Looking only at speech behaviors gives us an incomplete and inaccurate picture of stuttering, then. Stuttering is greater than the type and amount of speech behaviors. Certain phenomena are associated with stuttering and are not associated with other communication disorders or with normal fluency.
In addition to the core behaviors of stuttering (part word repetitions, prolongations, and blockages), many people who stutter exhibit behaviors collectively referred to as accessory, or secondary behaviors. The secondary behaviors accompany the core behaviors and vary from person to person. They are learned behaviors which usually occur in a hierarchy from least noticeable to more and more conspicuous.
Tension and tremor are often the first two secondary behaviors to appear. Tension and tremor may begin to appear when the person who stutters realizes that her/his core stuttering behaviors are not acceptable to others. Or they may appear as the person attempts to regain control of the articulators and get the words flowing again. Tension appears first in the lips, tongue, and jaw, and may spread to other parts of the face, head and neck. Excessive tension can eventually lead to tremors of muscles. Tremors constitute involuntary muscle movements which can cause a person to feel out of control of that particular muscle or out of control of the ability to speak. Tremors can have a powerful effect on the person who stutters and lead the person to seek any possible way to avoid the tremor in the first place or to escape the tremor and the feeling of loss of control. Behaviors such as using sudden, jerky movements to interrupt the tremor, or pushing the muscles or air harder to release the blocked speech, will occur in attempt to release the tremors, escape from the moment of stuttering, and get speech flowing smoothly again. These behaviors are often called escape or releasing devices. Some clinicians believe that tremors hold the seeds of fear. The tremors and fear, together, lead the person who stutters into a downward spiral involving layers of escaping, covering up and avoiding.
A variety of secondary behaviors arise as reactions to the fear of stuttering. People who stutter can build up intense fears in response to the loss of control that they feel or in response to the penalty that they experience from listeners. Avoidance behaviors may constitute the largest group of behaviors developed in response to fear. People who stutter will do a variety of things to avoid a moment of stuttering and the subsequent loss of control and listener penalty. Some common examples include substituting words that they think are easier to say for the ones they fear stuttering on, talking around a word and not saying it at all, pausing and pretending to think, and avoiding talking altogether. When people who stutter have successfully avoided a moment of stuttering the fears does not subside as completely as we might expect. Instead they have to maintain their vigilance to avoid the next possible moment of stuttering, and the next, and the next.
If a person who stutters can not avoid a word or situation altogether, then s/he may try to postpone that feared word until s/he can say it without stuttering. The person may try to time the speech attempt with the moment when their intense fear subsides. Examples of postponement devices include fillers, pausing, repeating a previous word or phrase many times until the target feared word feels like it will come out smoothly.
Sometimes people who stutter will use starter devices to help them get a running start in preparation for the feared word. Timing devices such as eye blinking, stomping a foot, or tapping a finger, often fall into this category. Finally, people who stutter sometimes try to disguise or cover up their stuttering so that it is less noticeable to listeners. Behaviors such as turning one's head away while talking, putting a hand over the mouth while talking, laughing, talking at a very fast rate or at a very low volume may fall into this category.
It's amazing how these secondary behaviors ever come to be in the first place. Often times a person who stutters will do something at some point to avoid, postpone, disguise, or release a moment of stuttering in order to avoid the penalty and feeling of loss of control. By coincidence, when the person turns her/his head to the left during a feared word, for example, s/he doesn't stutter. The person makes a cause-effect connection between that new behavior and the release of the stuttering behavior. Because turning the head to the left is a new behavior, it distracts the person's attention from the stuttering and seems to work at reducing or circumventing the stuttering. Unfortunately, the behavior "works" only for a short time until the distracting quality wears off. By then, the behavior has become a habit and now the person stutters and turns her/his head to the left. The person now needs to look for a new behavior to avoid those feared moments of stuttering. People who stutter sometimes develop elaborate collections of behaviors to avoid, reduce, or minimize the core stuttering behaviors. Ironically, the very behaviors the individual uses to minimize the stuttering end up making it more abnormal and distracting.
Covert features of stuttering
Core behaviors and secondary behaviors of stuttering are visible and audible, making them relatively easy to witness and to measure. People who stutter often experience some internal phenomena that are not visible or audible to listeners and that cannot be easily measured. Most of these covert features of stuttering are emotions.
Before a moment of stuttering, most people who stutter report feeling fear. Fear is the expectation of something unpleasant and threatening. They may fear the loss of control or may fear the penalty that they expect from their listener. These fears can become attached to specific sounds or words, to situations, such as the telephone, or to people. During a moment of stuttering, many people who stutter report feeling confusion or mental blankness. They may not be able to see a visual stimulus, such as a flashing light, or hear an auditory stimulus, such as a beeping noise, or they may have difficulty judging the passage of time. When asked how long they thought a moment of stuttering was immediately after the moment, most people who stutter perceived the moment as longer in duration than it actually was.
After a moment of stuttering, people who stutter report a variety of feelings. We might expect relief to be the predominant feeling reported, however, relief is short lived. More common and stronger emotions reported after a moment of stuttering include frustration, embarrassment, guilt, shame, and anger.
Physiological features of stuttering
People who stutter often experience some internal, bodily phenomena that listeners may or may not perceive. Most of these phenomena have been measured in research studies. They tend to occur during moments of stuttering but not when the person is speaking fluently. Interestingly, most of these behaviors have been induced in people who do not stutter under conditions of communication stress.
Breathing abnormalities tend to occur often with stuttering and may occur in very young children. People who stutter may exhibit shallow breathing or may unwittingly hold their breath through a moment of stuttering. Vascular changes during moments of stuttering have been documented. Some stutterers experience a rapid heart rate and elevated blood pressure which causes their faces to turn red, while others may experience a drop in blood pressure causing their faces to turn pale.
Many people who stutter show changes in their galvanic skin response (GSR), the machine used in the lie detector test. Some research studies have found people who stutter to have an elevated GSR just before and during speaking, regardless of if they were stuttering at the time. Research using a palmer sweat index has found that many people who stutter show increased sweating of their palms just before a moment of stuttering. Finally, many people who stutter show changes in their eye movements during moments of stuttering. These include dilation of the pupils, vertical or horizontal twitching, and rolling of the eyes upward in the sockets.
These physiological phenomena are not totally unique to people who stutter. In fact, most of us will experience these physiological changes when we find ourselves feeling afraid, anxious, or excited. These phenomena are part of the human flight or fight response to threatening and scary circumstances. Public speaking can induce these behaviors in most of us. For people who stutter, however, even the most common place communication situation can represent a threatening situation and precipitate the flight or fight response.
Speech dysfluencies constitute only a small part of the overall disorder of stuttering. Other characteristics seem to get added to these core behaviors in layers, beginning with the feeling of loss of control of the speech muscles. When we consider that each act of stuttering may represent a loss of control over the speech muscles, it is no wonder that people who stutter become concerned, frightened, and reluctant to speak. Imagine sometimes having control of a muscle and sometimes not, with no way to predict when you will have that control and when you will not. Then imagine that this random loss of control happens hundreds of times each day of your life. From this perspective the secondary behaviors, emotional reactions, and physiological responses make sense. It also makes sense that regaining the feeling of control over the speech muscles is important for breaking the chain of events that perpetuate the fear and the stuttering.
posted January, 2001