Stuttering
Stuttering is a speech
disorder in which the normal flow of speech is disrupted by frequent repetitions
or prolongations of speech sounds, syllables or words or by an individual's
inability to start a word. The speech disruptions may be accompanied by rapid
eye blinks, tremors of the lips and/or jaw or other struggle behaviors of the
face or upper body that a person who stutters may use in an attempt to speak.
Certain situations, such as speaking before a group of people or talking on the
telephone, tend to make stuttering more severe, whereas other situations, such
as singing or speaking alone, often improve fluency.
Stuttering may also be referred to as stammering, especially in England, and
by a broader term, disfluent speech. Stuttering is different from two additional
speech fluency disorders, cluttering, characterized by a rapid, irregular speech
and spasmodic dysphonia, a voice disorder.
How is speech normally produced?
Speech is normally produced through a series
of precisely coordinated muscle movements involving respiration (the breathing
mechanism), phonation (the voicing mechanism) and articulation (throat, palate,
tongue, lips and teeth). These muscle movements are initiated, coordinated and
controlled by the brain and monitored through the senses of hearing and touch.
Before speaking, an individual takes a breath and the vocal folds (or vocal
cords), which are two bands of muscular tissue located in the voice box directly
above the trachea or windpipe, must come together. The air that is held in the
lungs is gradually released, passing through the gently closed vocal folds thus
causing vibration and producing the voice. The sound of the voice is passed
through the throat and is directed into the mouth for most speech sounds, or
into the nose for nasal sounds such as "m," "n" and "ng." The palate, tongue,
jaw and lips move in precise ways to modify the sounds in order to make speech
sounds.
Who stutters?
It is estimated that over three million Americans stutter.
Stuttering affects individuals of all ages but occurs most frequently in young
children between the ages of 2 and 6 who are developing language. Boys are three
times more likely to stutter than girls. Most children, however, outgrow their
stuttering, and it is estimated that less than 1 percent of adults stutter.
Many individuals who stutter have become successful in careers that require
public speaking. The list of individuals includes Winston Churchill, actress
Marilyn Monroe, actors James Earl Jones, Bruce Willis and Jimmy Stewart, and
singers Carly Simon and Mel Tillis, to name only a few.
What causes stuttering?
Scientists suspect a variety of causes. There is
reason to believe that many forms of stuttering are genetically determined. The
precise mechanisms causing stuttering are not understood.
The most common form of stuttering is thought to be developmental, that is,
it is occurring in children who are in the process of developing speech and
language. This relaxed type of stuttering is felt to occur when a child's speech
and language abilities are unable to meet his or her verbal demands. Stuttering
happens when the child searches for the correct word. Developmental stuttering
is usually outgrown.
Another common form of stuttering is neurogenic. Neurogenic disorders arise
from signal problems between the brain and nerves or muscles. In neurogenic
stuttering, the brain is unable to coordinate adequately the different
components of the speech mechanism. Neurogenic stuttering may also occur
following a stroke or other type of brain injury.
Other forms of stuttering are classified as psychogenic or originating in the
mind or mental activity of the brain such as thought and reasoning. Whereas at
one time the major cause of stuttering was thought to be psychogenic, this type
of stuttering is now known to account for only a minority of the individuals who
stutter. Although individuals who stutter may develop emotional problems such as
fear of meeting new people or speaking on the telephone, these problems often
result from stuttering rather than causing the stuttering. Psychogenic
stuttering occasionally occurs in individuals who have some types of mental
illness or individuals who have experienced severe mental stress or anguish.
Scientists and clinicians have long known that stuttering may run in families
and that there is a strong possibility that some forms of stuttering are, in
fact, hereditary. No gene or genes for stuttering, however, have yet been found.