Estimates of the Prevalence of Speech and Motor Speech Disorders in Youth With 22q11.2 Deletion Syndrome

Abstract

Purpose Speech sound disorders and velopharyngeal dysfunction are frequent features of 22q11.2 deletion syndrome (22q). We report the first estimate of the prevalence of motor speech disorders (MSDs) in youth with 22q. Method Seventeen children and adolescents with 22q completed an assessment protocol that included a conversational speech sample. Data reduction included phonetic transcription, perceptual speech ratings, prosody-voice coding, and acoustic analyses. Data analyses included 3 motor speech measures and a cross-classification analytic. Prevalence estimates of speech and MSDs in youth with 22q were compared with estimates in speakers with other complex neurodevelopmental disorders: Down syndrome, fragile X syndrome, and galactosemia. Results Results indicated that 58.8% of the participants with 22q met criteria for speech delay, and 82.4% of the participants met criteria for MSDs, including 29.4% with speech motor delay, 29.4% with childhood dysarthria, 11.8% with childhood apraxia of speech, and 11.8% with concurrent childhood dysarthria and childhood apraxia of speech. MSDs were not significantly associated with velopharyngeal dysfunction. Conclusions In summary, 82.4% of the participants with 22q met criteria for 1 of 4 MSDs, predominantly speech motor delay and childhood dysarthria. Cross-validation of the present findings would support viewing MSDs as a core phenotypic feature of 22q.

Figure 1.

Estimates of the prevalence of speech and motor speech disorders in 17 persons with 22q11.2 deletion (a) and 45 persons with Down syndrome (b).

Figure 2.

Estimates of the prevalence of speech and motor speech disorders in 28 persons with fragile X syndrome (a) and 31 persons with galactosemia (b).

Figure 3.

Descriptive and inferential statistics comparing 22q11.2 deletion syndrome (22q) speech and motor speech prevalence findings with findings for participants with one of the other three complex neurodevelopmental disorders in Figures 1 and 2. DS = Down syndrome; FXS = fragile X syndrome; GAL = galactosemia; NSA = normal(ized) speech acquisition; SE = speech errors; PSE = persistent speech errors; SD = speech delay; PSD = persistent speech delay; MSD = motor speech disorder; SMD = speech motor delay; CD = childhood dysarthria; CAS = childhood apraxia of speech.

Figure B1.

Summary of the procedure used by the Speech Disorders Classification System (SDCS) to classify a speaker's motor speech status. PVSP = Prosody-Voice Screening Profile.