Developmental speech fluency disorder

Essential (Required) Features:

• Frequent or pervasive disruption of the normal rhythmic flow and rate of speech characterized by repetitions and prolongations in sounds, syllables, words, and phrases, as well as blocking (inaudible or silent fixations or inability to initiate sounds) and word avoidance or substitutions.
• The speech dysfluency is persistent over time.
• The onset of speech dysfluency occurs during the developmental period and speech fluency is markedly below what would be expected for age.
• Speech dysfluency results in significant impairment in social communication or in personal, family, social, educational, occupational or other important areas of functioning.
• The speech dysfluency is not better accounted for by a Disorder of Intellectual Development, a Disease of the Nervous System, a sensory impairment, or a structural abnormality.

Additional Clinical Features:

• Developmental Speech Fluency Disorder includes cluttering, in which speech tends to be rapid, erratic and dysrhythmic, with breakdown in fluency and clarity, often with deletion or collapsing of syllables and omissions of word endings.
• Developmental Speech Fluency Disorder may be accompanied by physical tension in the speech musculature, as well as body tension, struggle behaviour, and secondary mannerisms, such as facial grimacing, eye blinking, head movements, and arm and leg movements such as leg tapping or fist clenching.
• Developmental Speech Fluency Disorder is often accompanied by anxiety in anticipation of speaking and avoidance of speaking.
• The extent of the problem varies across situations and can be more severe when there is pressure to communicate.
• Developmental Speech Fluency Disorder may be associated with a broader range of speech and language abnormalities.
• Occasionally, onset of dysfluency can be related to a significant psychological event such as bereavement and is sometimes referred to as ‘psychogenic stammering’. When this occurs during the developmental period, it may be diagnosed as Developmental Speech Fluency Disorder.
• Approximately 60% of children with Developmental Speech Fluency Disorder exhibit co-occurring Developmental Speech and Language Disorders.
• Among adolescents and adults with chronic speech dysfluencies, social anxiety is common and may exacerbate dysfluency. As many as 40 – 60% of these individuals meet the diagnostic requirements for Social Anxiety Disorder.

Boundary with Normality (Threshold):

• Many typically developing children show minor dysfluencies during the preschool years.

Course Features:

• The course of Developmental Speech Fluency Disorder may be relatively brief in many cases with the majority of children (65 – 85%) remitting, without intervention, prior to puberty. Among these children, recovery is typically within the first two years after onset.
• The impact of Developmental Speech Fluency Disorder may be evident as early as age 3, with impairments in emotional, behavioural, and social domains compared to typically-developing peers.
• A more persistent course is associated with male gender, family history of Developmental Speech Fluency Disorder; age at onset of greater than 3 to 4 years of age; duration of more than 1 year; and co-occurring Developmental Language Disorder. More severe presentations of the disorder in childhood are more likely to persist into adolescence and adulthood.

Developmental Presentations:

• Developmental Speech Fluency Disorder emerges early in the developmental period, typically between ages two-and-a-half and four years. Five to 8% of preschool children exhibit stuttering. Eighty to 90% of cases develop by age six, and onset after age nine is rare. The lifetime incidence of stuttering is estimated at 5% whereas population prevalence is estimated at approximately 1%.
• Dysfluency tends to emerge gradually and may worsen as the individual becomes aware of their fluency difficulty. This may lead to development of mechanisms to avoid dysfluency or the associated emotional discomfort, further impairing speech (e.g., avoiding public speaking or limiting speech to simple and short phrases).

Sex- and/or Gender-Related Features:

• Across the developmental period, boys are more commonly affected. Among preschool children, the ratio of boys to girls with Developmental Speech Fluency Disorder is estimated at 1.5:1. However, females are more likely to remit. Throughout school age and into adulthood, males are estimated to outnumber females by ratio of 4:1.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Developmental Speech Sound Disorder and Developmental Language Disorder: Like Developmental Speech Fluency Disorder, Developmental Speech Sound Disorder and Developmental Language Disorder can result in reduced intelligibility that significantly affects communication. Developmental Speech Sound Disorder is characterized by errors of pronunciation that are outside the limits of normal variation for chronological or developmental age. Developmental Language Disorder is characterized by persistent difficulties in the acquisition, understanding, production or use of language. In contrast, Developmental Speech Fluency Disorder is characterized by disruption of the normal rhythmic flow and rate of speech. If the diagnostic requirements for both Developmental Fluency Disorder and another Developmental Speech and Language Disorder are met, both diagnoses may be assigned.
• Boundary with Primary Tics or Tic Disorders, including Tourette Syndrome: Dysfluency associated with other movements of the face or body that coincide in time with repetitions, prolongations, or pauses in speech flow needs to be differentiated from complex tics. Tics do not involve the marked speech dysfluency that characterizes a Developmental Speech Fluency Disorder.
• Boundary with Diseases of the Nervous System: Diseases of the Nervous System affecting the anatomical and functional mechanisms for speech output can sometimes give rise to speech dysfluency but are distinguished on examination by the presence of positive neurological signs.