Developmental speech sound disorder

Essential (Required) Features:

• Persistent errors of pronunciation, articulation, or phonology (i.e., how language-based sounds are combined in culture-typical speech) that manifest as developmentally typical speech sound errors that persist substantially beyond the expected age or as atypical speech sound errors for the language spoken (e.g., word initial consonant deletion for English-speaking children).
• The onset of speech sound difficulties occurs during the early developmental period.
• Speech sound difficulties result in significant limitations in the ability to communicate due to reduced intelligibility of speech.
• The speech errors are not better accounted for by a Disease of the Nervous System affecting the brain, peripheral nerves, or neuromusculature (e.g., cerebral palsy, myasthenia gravis), a sensory impairment (e.g., sensory neural deafness), or a structural abnormality (e.g., cleft palate) or another medical condition.

Additional Clinical Features:

• Children with Developmental Speech Sound Disorder may exhibit delays in the acquisition, production and perception of spoken language.
• Phonological speech sound errors may be consistent or inconsistent. They often involve classes of sounds (e.g., incorrectly producing sounds in the same manner), a different place of articulation, or changes in syllable structure (e.g., deletion of final consonants or reducing consonant clusters to single consonants).
• If the speech errors are consistently produced, familiar listeners may be able to accommodate and decode the speech. However, when the rate of speech increases even familiar listeners may not be able to understand the individual.
• Developmental Speech Sound Disorder may be associated with imprecision and inconsistency of oral movements required for speech especially in young children (also called childhood apraxia or dyspraxia of speech) resulting in difficulty producing sequences of speech sounds, specific consonants and vowels, and appropriate prosody (intonation and rhythm of speech). There may be some associated oral-motor dysfunction affecting early feeding, sucking and chewing, blowing, and imitating oral movements and speech sounds but not with the weakness, slowness, or incoordination found in Dysarthria.
• Developmental Speech Sound Disorder commonly co-occurs with other Neurodevelopmental Disorders, such as Attention Deficit Hyperactivity Disorder, Developmental Speech Fluency Disorder, and Developmental Language Disorder.

Boundary with Normality (Threshold):

• Children vary widely in the sequence and age at which they acquire speech sounds. Such normal variation does not reflect the presence of Developmental Speech Sound Disorder. In contrast, children with Developmental Speech Sound Disorder exhibit persistent problems that cause significant limitations in the ability to communicate due to reduced intelligibility of speech. Up until the age of 4 years, various speech sound errors are common among children with typically developing speech sound acquisition, but communication remains relatively intact despite these errors relative to same-aged peers.

Course Features:

• Many young children with Developmental Speech Sound Disorder experience remission by school-age. Among young children diagnosed in early childhood, up to 50 – 70% will exhibit academic difficulties throughout their schooling, even if the speech sound difficulties themselves have remitted.
• As compared with children and adolescents with a sole diagnosis of Developmental Speech Sound Disorder, those with a co-occurring Developmental Language Disorder are more likely to develop other Mental, Behavioural or Neurodevelopmental Disorders such as Anxiety or Fear-Related Disorders or Attention Deficit Hyperactivity Disorder. They also exhibit greater difficulties academically, socially, and adaptively by late childhood and adolescence.

Developmental Presentations:

• Prevalence rates vary but generally decrease with age such that prevalence can be as high as 16% at age three or four, approximately 4% at age six, and 3.6% by age eight. Therefore, many pre-school children diagnosed with Developmental Speech Sound Disorder exhibit typical speech sound development by the time they begin school.
• Some children with symptoms of Developmental Speech Sound Disorder early in life may only experience interference with functioning when they enter school when the demands of the learning environment exceed their current abilities.
• Co-occurrence of other Neurodevelopment Disorders is more likely among children with persistent Developmental Speech Sound Disorder (whose speech sound errors continue beyond age eight or nine). In particular, these children are more likely to develop language impairments and reading difficulties, and tend to experience worse outcomes.

Sex- and/or Gender-Related Features:

• Developmental Speech Sound Disorder is more common in boys, especially at younger ages. Early speech difficulties in girls appear more likely to resolve by school age. Gender differences decline with age; the ratio of boys affected compared to girls appears to be 2:1 or 3:1 in early childhood and to decline to 1.2:1 by age 6.
• Boys are more likely to experience co-occurring language impairments.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Disorders of Intellectual Development: Individuals with a Disorder of Intellectual Development may exhibit impaired speech production. However, individuals with Developmental Speech Sound Disorder do not typically also have significant limitations in intellectual functioning and adaptive behaviour. If speech production difficulties require separate clinical attention in the context of a Disorder of Intellectual Development, an additional diagnosis of Developmental Speech Sound Disorder may be assigned.
• Boundary with Developmental Speech Fluency Disorder and Developmental Language Disorder: Like Developmental Speech Sound Disorder, Developmental Speech Fluency Disorder and Developmental Language Disorder can result in reduced intelligibility that significantly affects communication. Developmental Speech Fluency Disorder is characterized by disruption of the normal rhythmic flow and rate of speech. Developmental Language Disorder is characterized by persistent difficulties in the acquisition, understanding, production or use of language. In contrast, Developmental Speech Sound Disorder is characterized by errors of pronunciation that are outside the limits of normal variation for chronological or developmental age.
• Boundary with Selective Mutism: Selective Mutism is characterized by consistent selectivity in speaking, such that a child demonstrates adequate speech production in specific situations, typically at home, but predictably fails to speak in others, typically at school. Selective Mutism can occur in the presence of Developmental Speech Sound Disorder, and both diagnoses may be assigned if warranted.
• Boundary with Dysphonia: Dysphonia is characterized by abnormal voice production or absences of vocal quality, pitch, loudness, resonance, or duration. It can be caused by voice strain or overuse, by structural laryngeal anomalies or by Diseases of the Nervous System. It may result in the distortion of speech sounds due to the abnormal voice quality. In contrast, Developmental Speech Sound Disorder involves the omission or substitution of speech sounds and also includes distortion of speech sounds (e.g., due to incorrect tongue placement) rather than abnormal voice quality characteristic of Dysphonia.
• Boundary with Dysarthria: Dysarthria is a motor speech disorder directly attributable to a Disease of the Nervous System or to either congenital or acquired brain injury. Dysarthria is characterized by difficulties with the range, rate, force, coordination, and sustainability of movements throughout the vocal tract (i.e., trunk, larynx, palate, tongue, lips, jaw, and face) that are required for speech. These motor difficulties often also cause frank difficulties in eating, drinking, swallowing or saliva control. A diagnosis of Developmental Speech Sound Disorder should not be assigned in these cases. Rather, a diagnosis of Secondary Speech or Language Syndrome should be assigned in addition to the associated medical condition if the speech sound difficulties are a specific focus of clinical attention.
• Boundary with Secondary Speech or Language Syndrome: The diagnosis of Developmental Speech Sound Disorder should not be assigned in the presence of a Disease of the Nervous System affecting the brain, peripheral nerves, or neuromusculature (e.g., cerebral palsy, myasthenia gravis), sensory impairment (e.g., sensory neural deafness), or structural impairment (e.g., cleft palate), although speech sound production difficulties may be a presenting feature of any of these conditions. In these cases, a diagnosis of Secondary Speech or Language Syndrome should be assigned in addition to the associated medical condition if the speech sound difficulties are a specific focus of clinical attention.