An N-of-1 Randomized Controlled Trial of Interventions for Children With Inconsistent Speech Sound Errors

Area of Science:

• Speech-language pathology
• Child language acquisition
• Neurodevelopmental disorders

Background:

• Children with inconsistent speech errors often have underlying motor planning or phonological planning deficits.
• Tailoring interventions to specific deficits can optimize treatment outcomes.
• Previous research suggests different therapeutic approaches may be more effective for distinct underlying impairments.

Purpose of the Study:

• To test if children with inconsistent speech errors respond differently to specific interventions based on their primary impairment.
• To investigate if auditory-motor integration (AMI) is superior for motor planning deficits.
• To determine if phonological memory and planning (PMP) is superior for phonological planning deficits.

Main Methods:

• An N-of-1 randomized controlled trial involving 12 children with diagnosed motor planning (n=7) or phonological planning (n=5) deficits.
• Each child received three interventions: AMI, PMP, and a control (CTL) condition, in a randomized order over 6 weeks.
• Interventions targeted acoustic-phonetic knowledge and feedback integration (AMI) or segmenting and recompiling phonological plans (PMP).

Main Results:

• Children with motor planning deficits showed significant benefits from AMI compared to PMP for both same-day (p=2.01E-04) and next-day (p=2.97E-03) probes.
• Children with phonological planning deficits demonstrated significant benefits from PMP compared to AMI for both same-day (p=1.22E-02) and next-day (p=1.32E-02) probes.
• Response to the CTL intervention varied within both diagnostic groups.

Conclusions:

• The child's underlying psycholinguistic deficit significantly predicts their response to specific speech interventions.
• Auditory-motor integration (AMI) therapy is more effective for children with motor planning deficits.
• Phonological memory and planning (PMP) therapy is more effective for children with phonological planning deficits.