46 Chapter 3
(Stuttering Foundation of Amer i ca, 2015). Most stuttering begins in childhood, but can also occur
in adults. The incidence and prevalence of stuttering vary among cultures; generally in the United
States, about 1% of the population stutters. According to the Stuttering Foundation of Amer i ca
(2015), more than 70 million people worldwide stutter. Studies on the incidence and prevalence of
stuttering are difficult to compare and analyze because there are many definitions of stuttering,
the disorder usually develops gradually, and individuals are never perfectly f luent all the time.
Definition of Stuttering
Speech f luency occurs on a continuum; a range of normal dysf luencies appears in human
speech patterns, and there is no clear line separating normally fluent speech from stuttering.
When talking, all persons repeat sounds, syllables, words, and phrases. They also hesitate and
pause during speech, particularly when distracted, when thinking about the topic, or when select-
ing the appropriate word to use. Sometimes persons prolong sounds during speech and interject
words and sounds, such as “you know” and “uh.” These repetitions, prolongations, and hesitations
are usually produced subconsciously and are typical speech patterns occurring in all persons.
However, some persons display these be hav iors more frequently and with more severity, and they
consider themselves stutterers. Stuttering and cluttering, a verbal thought- organ ization disorder,
are the two major f luency- disrupting speech pathologies. In cluttering, the speaker is usually
unaware of the dysf luencies, speaks rapidly, and has a brief attention span and poor concentra-
tion. Because speech- language pathologists rarely treat cluttering as a clinical entity, this chapter
addresses the diagnosis and treatment of stuttering.
There are many definitions of stuttering, but Van Riper’s (1973, 1992) has the most clinical use.
He defines stuttering as a word improperly patterned in time and the speaker’s reaction thereto.
According to Van Riper, a person who stutters has an abnormal number of dysf luencies and reacts
negatively to them. Words are improperly patterned in time by repetitions, prolongations, and
blocks in the f low of speech, and the negative emotions may include anxiety, fear, embarrassment,
and guilt. Persons with stuttering may also use certain be hav iors to avoid or escape from the
moment of stuttering. These can take the form of avoiding eye contact, closing the eyes, slapping
the hand, jerking the head, and others. The following is a comprehensive definition of a person
who stutters, and it serves as the basis for the discussion of this communication disorder:
An individual who improperly patterns phonemes, syllables, words and/or phrases in time;
who experiences classically- conditioned negative emotional reactions to disf luent speech
and associated stimuli and who may engage in vis i ble avoidance and escape be hav iors when
confronted with disf luent speech or associated stimuli. (Tanner, Belliveau, & Siebert, 1995,
p. 6)Etiology of Stuttering: Nature or Nurture?
The etiology of stuttering has been debated for de cades, and one question consistently arises:
Is stuttering caused by learning and environmental factors or is it a result of physical, organic
irregularities? Over the years, organic, learning, and psychological theories have been advanced
to explain the etiology of stuttering. At the core of this debate is the age- old question asked about
many human maladies: Is stuttering caused by nature or nurture? Currently, many speech scien-
tists and clinicians believe that the organic theories explain why some persons develop stuttering.
According to the organic theories of stuttering, some persons are predisposed to stuttering
because of neurological or physical anomalies. They have brain damage or irregularities, neurolog-
ical impairments, or muscular deficits that impair speech fluency. Also, some authorities believe