Stuttering is often a developmental disorder beginning in early childhood and continuing into adulthood at least 20% of children of those affected. The mean onset of stuttering is 30 months. Although there is variability, early stuttering behaviors usually consist of word or syllable repetitions, and secondary behaviors such as tension, avoidance or escape behaviors are absent. Most young children are unaware of the interruptions in their speech.

With early stutterers, dis fluency may be episodic, and periods of stuttering are followed by periods of relative fluency. Though the rate of early recovery is very high, with time a young stutterer may transition from easy, relaxed repetition to more tense and effortfull stuttering, including blocks and prolongations.

Some propose that parental reaction may affect the development of chronic stutter. Recommendations to slow down, take a breath, say it again, etc may increase the child’s anxiety and fear, leading to more difficulties with speaking and, in the “cycle of stuttering” to ever yet more fear, anxiety and expectation of stuttering. With time secondary stuttering including escape behaviors such eye blinking, lip movements, etc. may be used, as well as fear and avoidance of sounds, words, people, or speaking situations.

Eventually, many become fully aware of their disorder and begin to identify themselves as “stutterers.” With this may come deeper frustration, embarrassment and shame.

Other, rarer, pattern of stuttering development have been described, including sudden onset with the child being unable to speak, despite attempts to do so. The child usually blocks silently of the first sound of a sentence, and shows high levels of awareness and frustration. Another variety also begins suddenly with frequent word and phrase repetition, and do not develop secondary stuttering behaviors.

No single, exclusive cause of developmental stuttering is known – evidence includes genetic basis, Children who have first-degree relatives who stutter are three times as likely to develop a stutter.

However, twin and adoption studies suggest that genetic factors interact with environmental factors for stuttering to occur, and forty to seventy percent of stutterers have no family history of the disorder. There is evidence that stuttering is more common in children who also have concomitant speech, language, learning or motor difficulties.

In some stutterers, congenital factors may play a role. These may include physical trauma at or around birth, including cerebral palsy, retardation, or stressful situations, such as the birth of a sibling, moving, or a sudden growth in linguistic ability.

In rare cases, stuttering may be acquired in adulthood as the result of a neurological event such as a head injury, tumor, stroke or drug abuse/misuse. The stuttering has different characteristics from its developmental equivalent: it tends to be limited to part-word or sound repetitions, and is associated with a relative lack of anxiety and secondary stuttering behaviors. Techniques such as altered auditory feedback (see below) which may promote fluency in stutterers with the developmental condition, are not effective with the acquired type.

Psychogenic stuttering may also arise after a traumatic experience such as a bereavement, the breakup of a relationship or as the psychological reaction to physical trauma. Its symptoms tend to be homogeneous: the stuttering is of sudden onset and associated with a significant events, it is constant and uninfluenced that different speaking situations, and there is initial little awareness or concern shown by the speaker in their speech.

There is clear empirical evidence for structural and functional differences in the brains of stutterers. Research is complicated somewhat by the possibility that such differences could be the consequences of stuttering rather than a cause, but recent research on older children confirm structural differences thereby giving strength to the argument that at least some of the differences are not a consequence of stuttering.

Auditory processing deficits have also been proposed as a cause of stuttering. Stuttering is less prevalent in deaf and hard of hearing individuals, and stuttering may be improved when auditory feedback is altered, such as masking, delayed auditory feedback (DAF), or frequency altered feedback.

There is some evidence that the functional organization of the auditory cortex may be different in stutterers.

There is evidence of differences in linguistic processing between stutterers and non-stutterers. Brain scans of adult stutterers have found increased activation of the right hemisphere, which is associated with emotions, than in the left hemisphere, which is associated with speech. In addition reduced activation in the left auditory cortex has been observed.

Speech Therapy

Fluency shaping therapy, also known as “speak more fluently” or “prolonged speech”, trains stutterers to speak fluently by controlling their breathing, phonation, and articulation (lips, jaw, and tongue). It is based on operant conditioning techniques.

Stutterers are trained to reduce their speaking rate by stretching vowels and consonants, and using other fluency techniques such as continuous airflow and soft speech contacts. The result is very slow, monotonic, but fluent speech used only in the speech clinic. After the stutterer masters these fluency skills, the speaking rate and intonation are increased gradually. This more normal-sounding, fluent speech is then transferred to daily life outside the speech clinic, though lack of speech naturalness at the end of treatment remains a frequent criticism. Fluency shaping approaches are often taught in intensive group therapy programs, which may take two to three weeks to complete.

Stuttering Modification Therapy

The goal of stuttering modification therapy is not to eliminate stuttering but to modify it so that stuttering is easier and less effortful.The rationale is that since fear and anxiety causes increased stuttering, using easier stuttering and with less fear and avoidance, stuttering will decrease.

The stuttering modification therapy has four overlapping stages:

In the first stage, called identification, the stutterer and clinician identify the core behaviors, secondary behaviors, and feelings and attitudes that characterize the stuttering.

In the second stage, called desensitization, the stutterer works to reduce fear and anxiety by freezing stuttering behaviors, confronting difficult sounds, words and situations, and intentionally stuttering (”voluntary stuttering”).

In the third stage, called modification, the stutterer learns “easy stuttering.” This is done by “cancellations” (stopping in a dysfluency, pausing a few moments, and saying the word again); “pull-outs,” or pulling out of a dysfluency into fluent speech; and “preparatory sets,” or looking ahead for words one may stutter on, and using “easy stuttering” on those words.

In the fourth stage, called stabilization, the stutterer prepares practice assignments, makes preparatory sets and pull-outs automatic, and changes their self-concept from being a person who stutters to being a person who speaks fluently most of the time but who occasionally stutters mildly.

Electronic Fluency Devices

Altered auditory feedback, so that stutterers hears their voice differently, has been used for over 50 years in the treatment of stuttering. Altered auditory feedback effect can be produced by speaking in chorus with another person, by providing blocking out the stutterer’s voice while talking (masking), by delaying the stutterer’s voice slightly (delayed auditory feedback) and/or by altering the frequency of the feedback (frequency altered feedback). Studies of these techniques have had mixed results, with some stutterers showing substantial reductions in stuttering, while others improved only slightly or not at all. In a 2006 review of the efficacy of stuttering treatments, none of the studies on altered auditory feedback met the criteria for experimental quality, such as the presence of control groups.

Anti-Stuttering Medications

The effectiveness of pharmacological agents, such as anti-convulsants, anti-depressants, antipsychotic and anti hypertensive medications, and dopamine antagonists in the treatment of stuttering has been evaluated in studies involving both adults and children. A comprehensive review of pharmacological treatments of stuttering in 2006 concluded that few of the drug trials were methodologically sound. Of those that were, only one, not unflawed study, showed a reduction in stuttering to less than 5%. In addition, potentially serious side effects of pharmacological treatments were noted.

Prognosis

Among preschoolers, the prognosis for recovery is good. Based on research, about 65% of preschoolers who stutter recover spontaneously in the first two years of stuttering, and about 74% recover by their early teens. In particular, girls seem to recover well. For others, early intervention is effective in helping the child achieve normal fluency.

Once stuttering has become established, and the child has developed secondary behaviors, the prognosis is more guarded,and only 18% of children who stutter after five years recover spontaneously.However, with treatment young children may be left with little evidence of stuttering.

With adult stutterers, there is no known cure, though they may make recovery with intervention. Stutterers often learn to stutter less severely and be less affected emotionally, though others may make no progress with therapy.