Considerations for identifying subtypes of speech sound disorder

Area of Science:

• Pediatric Speech-Language Pathology
• Childhood Communication Disorders
• Linguistic and Auditory Sciences

Background:

• Speech sound disorders (SSDs) in children are highly diverse, necessitating subtype differentiation for tailored treatment.
• Accurate diagnosis of specific SSD subtypes is essential for selecting the most effective therapeutic approaches.
• Overlapping surface characteristics among subtypes like consistent phonological disorder (CPD), inconsistent phonological disorder (IPD), and childhood apraxia of speech (CAS) present diagnostic challenges.

Purpose of the Study:

• To investigate the distinct underlying processes differentiating phonological processing, phonological planning, and motor planning deficits in children with SSDs.
• To establish diagnostic markers for identifying specific SSD subtypes based on underlying causal factors.
• To inform the development of personalized treatment strategies for children experiencing various forms of SSDs.

Main Methods:

• A comprehensive literature review was conducted to identify diagnostic signs at the levels of distal causes, proximal factors, and surface characteristics of SSDs.
• Analysis focused on linking observable speech characteristics to underlying explanatory proximal factors, including speech perception, phonological memory, and speech-motor control.
• Diagnostic indicators for consistent phonological disorder (CPD), inconsistent phonological disorder (IPD), and childhood apraxia of speech (CAS) were examined.

Main Results:

• Consistent phonological disorder (CPD) is characterized by predictable speech errors linked to speech perception deficits.
• Inconsistent phonological disorder (IPD) is associated with difficulties in phoneme selection and sequencing, manifesting as within-word inconsistency and impaired phonological memory.
• Childhood apraxia of speech (CAS) is identified by motor planning deficits, evidenced by transcoding errors during syllable repetition and challenges with rapid, accurate articulation of specific sound sequences.

Conclusions:

• Children with SSDs represent a heterogeneous group, with significant overlap in surface characteristics, particularly in severe cases.
• Specific diagnostic signs, when linked to underlying causal factors, can differentiate between SSD subtypes.
• Personalized treatment for children with SSDs requires careful attention to underlying causal factors, supported by comprehensive assessments of phonological processing, planning, and motor skills.