Purpose: Speech and language development in individuals with Down syndrome is often delayed
and/or disordered and speech disfluencies appear to be more common. These disfluencies have
been labeled over time as stuttering, cluttering or both.

Findings: were usually generated from studies with adults or a mixed age group, quite often using
different methodologies, making it difficult to compare findings. Therefore, the purpose of this
study was to analyze and describe the speech disfluencies of a group, only consisting of children
with Down Syndrome between 3 and 13 years of age.

Method: Participants consisted of 26 Dutch-speaking children with DS. Spontaneous speech
samples were collected and 50 utterances were analyzed for each child. Types of disfluencies
were identified and classified into stuttering-like (SLD) and other disfluencies (OD). The criterion
of three or more SLD per 100 syllables (cf. Ambrose & Yairi, 1999) was used to identify stuttering.
Additional parameters such as mean articulation rate (MAR), ratio of disfluencies, and telescoping
(cf. Coppens-Hofman et al., 2013) were used to identify cluttering and to differentiate
between stuttering and cluttering.

Results & conclusion: Approximately 30 percent of children with DS between 3 and 13 years of
age in this study stutter, which is much higher than the prevalence in normally developing
children. Moreover, this study showed that the speech of children with DS has a different distribution
of types of disfluencies than the speech of normally developing children. Although
different cluttering-like characteristics were found in the speech of young children with DS, none
of them could be identified as cluttering or cluttering-stuttering.