Nonverbal communication skills in children with Prader-Willi syndrome (PWS)

Objective: Nonverbal communication skills provide a foundation for subsequent language, social, and cognitive development in young children. Prader-Willi syndrome (PWS) is a multiple congenital anomaly syndrome associated with mild to moderate mental retardation. This disorder is caused by various genetic defects: a 15q11-q13 deletion in approximately 70% of case, chromosome 15 uniparental disomy in approximately 29%, and imprinting center mutations in 1%-2%. Children with PWS often have language developmental delay, and difficulty maintaining social interactions with peers. However there is no research on the nonverbal communication skills of individuals with PWS. This study examined the nonverbal communication competence of children with PWS. Patients and Methods: All PWS subjects were confirmed by molecular genetic testing at the Molecular Cytogenetics Laboratory of National Cheng Kung University Medical Center from 1998 to 2003. The PWS group consisted of 13 children aged between 2 and 7 years. Twenty-six normal children were recruited who matched the PWS children's mental age, motor age, and socioeconomic status. An ESCS (early social communication scale) was used to assess nonverbal communication skills in all subjects. The procedures of analysis of variance were conducted to compare differences between initiation and response behaviors, and differences between low- and high-level behaviors. Results: We found that there were significant differences in initiation and response behaviors between the PWS and normal groups. PWS children undertook significantly more initiating joint attention behaviors but significantly fewer responses to joint attention behaviors compared to normal children. There were also significant differences between the 2 groups in low- and high-level behaviors. PWS children used significantly more low-level joint attention behaviors than did normal children. However, PWS children performed significantly fewer low- and high-level responses to joint attention behaviors as well as high-level request behaviors than did normal children. There was no significant difference in the other behavior patterns between the 2 groups. Conclusions: In this study we found significant differences in nonverbal communication skills between PWS and normal children. Children with PWS displayed significantly delayed development in high-level of nonverbal communication skills.