Down syndrome is a developmental disorder that causes varying degrees of physical and cognitive disability. It is the most common genetic condition and is caused by a chromosomal abnormality in which there is an extra copy of chromosome 21. 

Down Syndrome

The FOXP2 gene appears to be crucial for normal language acquisition. Children with mutations in this gene take longer times for language acquisition and show difficulty in executing particular language tasks. The pattern of brain activation also differ from children with normal FOXP2 genes when performing language tasks. 

FOXP2 gene in language acquisition

Speech may be impaired in certain genetic conditions, such as:

-Down Syndrome

-22q deletion

-FoxP2 gene mutation.

Cleveland State University

Santa Clara University

"Speech sound disorders" (SSD) is an umbrella term which refers to any communication disorder defined by persistent difficulty with speech sound production that interferes with speech intelligibility or prevents verbal communication of messages. 

The condition is marked by developmentally inappropriate errors in speech production, due to impairments in articulation and phonological processing which arise from a variety of limitations related to perception, speech motor, and/or linguistic processes. 

SSD can be subdivided into two primary groups: 1) articulation disorders (also known as phonetic disorders) and 2) phonological disorders. 

Speech Sound Disorder (SSD)

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed., Text revision). https://doi.org/10.1176/appi.books.9780890425596

DSM-5-TR

A. Persistent difficulty with speech sound production that interferes with speech intelligibility or prevents verbal communication of messages.

B. The disturbance causes limitations in effective communication that interfere with social participation, academic achievement, or occupational performance, individually or in any combination.

C. Onset of symptoms is in the early developmental period.

D. The difficulties are not attributable to congenital or acquired conditions, such as cerebral palsy, cleft palate, deafness or hearing loss, traumatic brain injury, or other medical or neurological conditions.

DSM-5-TR Diagnostic Criteria of Speech Sound Disorder

Associated features of Speech Sound Disorder include:

- Co-occurrence with language disorder
- Family history of speech or language disorders
- History of delay or incoordination in acquiring skills that also utilize the articulators and related facial musculature; including chewing, maintaining mouth closure, and blowing the nose
- Impaired motor coordination in other areas

Associated Features of Speech Sound Disorder

- Articulation of speech sounds follows a typical developmental
pattern, reflected in standard age norms. Mostly intelligible speech should be heard by 3 years of age. Children with speech sound disorder continue to use immature phonological simplification processes past the age most children can pronounce words clearly.

-  The most frequently mispronounced sounds in English also tend to be learned later, (l, r, s, z, th, ch, dzh, and zh). Misarticulation of any of these sounds by itself could be considered within normal limits up to age 8 years of age; however, when multiple sounds are involved, it is important to target some of those sounds as part of a plan to improve
intelligibility.

- Most children with speech sound disorder respond well to treatment and the disorder may not be lifelong. However when a language disorder's present prognosis is poorer it may be associated with a learning disorder.

Development and Course of Speech Sound Disorder

Speech Sound Disorder may have features that overlap with other speech patterns, conditions, or disorders, including:

- Normal variations in speech

- Hearing or other sensory impairment

- Structural deficits

- Dysarthria

- Selective mutism

Differential Diagnosis to Speech Sound Disorder

This includes the intersection of connections and/or research related to Speech Sound Disorder as a general category in other fields of study and research. Such fields include:

-TBD


Interdisciplinary Connections & Research Related to Speech Sound Disorder

American Speech-Language-Hearing Association. (n.d.). Speech Sound Disorders: Articulation and Phonology. American Speech-Language-Hearing Association. Retrieved May 31, 2023, from https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology/#collapse_9

The "Speech Sound Disorder (SSD)" concept node included paraphrased information from this source regarding the categorization of SSD into two groups: 1) Articulation Disorders and 2) Phonological Disorders. 

American Speech-Language-Hearing Association, n.d.

Namasivayam, A. K., Coleman, D., O’Dwyer, A., & van Lieshout, P. (2020). Speech Sound Disorders in Children: An Articulatory Phonology Perspective. Frontiers in Psychology, 10. https://doi.org/10.3389/fpsyg.2019.02998

The "Speech Sound Disorder (SSD)" concept node included paraphrased information form this source regarding the definition of SSD, specifically on the developmental errors arising from perception, speech motor issues, and/or linguistic impairments which contribute to SSD. 

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