Lala

Down Syndrome Research and Practice 10 (1), 10-22

10

Speech intelligibility and childhood verbal apraxia
in children with Down syndrome
Libby Kumin, Ph.D., CCC-SLP
Professor of Speech-Language Pathology
Loyola College in Maryland

Abstract – Many children with Down syndrome have difficulty with speech intelligibility. The
present study used a parent survey to learn more about aspecific factor that affects speech
intelligibility, i.e. childhood verbal apraxia. One of the factors that affects speech intelligibility for
children with Down syndrome is difficulty with voluntarily programming, combining, organising,
and sequencing the movements necessary for speech. Historically, this difficulty, childhood verbal
apraxia, has not been identified or treated in children withDown syndrome but recent research
has documented that symptoms of childhood verbal apraxia can be found in children with Down
syndrome. The survey examined whether and to what extent childhood verbal apraxia is currently
being identified and treated in children with Down syndrome. The survey then asked parents to
identify certain speech characteristics that occur always, frequently, sometimes ornever in their
child’s everyday speech. There were 1620 surveys received. Survey results indicated that approximately 15% of the parents responding to the survey had been told that their child has childhood
verbal apraxia. Examination of the everyday speech characteristics identified by the parents indicated that many more children are showing clinical symptoms of childhood verbal apraxiaalthough
they have not been given that diagnosis. The most common characteristics displayed by the subjects included decreased intelligibility with increased length of utterance, inconsistency of speech
errors, difficulty sequencing oral movements and sounds, and a pattern of receptive language
superior to expressive language. The survey also examined the impact of childhood verbal apraxia
on speechintelligibility. Results indicated that children with Down syndrome who have clinical
symptoms of childhood verbal apraxia have more difficulty with speech intelligibility, i.e. there was
a significant correlation between childhood verbal apraxia and parental intelligibility ratings. Children with apraxia often do not begin to speak until after age 5. There was a significant correlationbetween speech intelligibility and age at which the child began to speak, i.e. children who began to
speak after age 5 had lower parental intelligibility ratings. A diagnosis of difficulty with oral motor
skills is more frequently given than a diagnosis of apraxia; 60.2% of parents had been given this
diagnosis. According to survey results, it is rare (2%) for a diagnosis of childhood verbal apraxiato
be made without a diagnosis of difficulty with oral motor skills.
Keywords: Down syndrome, speech intelligibility, speech, childhood verbal apraxia, developmental apraxia of speech, oral motor, communication, special needs

Background information/need for
the study
Speech intelligibility has been defined as how clearly a
person speaks so that his or her speech is comprehensible
to alistener. (Leddy, 1999). Reduced speech intelligibility
is a widespread problem for children with Down syndrome
t hat has been documented in the literature in clinical case
studies, surveys, and reports (Buckley, 2000; Chapman
& Hesketh, 2000; Chapman et al., 1998; Hesselwood et

a l., 1995; Horstmeier, 1988; Kumin, 1994, 2001, 2002a,
2002b; Miller & Leddy, 1999, Rosin & Swift, 1999; Swift
&Rosin, 1990, Stoel-Gammon, 2001). Parents are aware
t hat speech intelligibility is a major problem for their children with Down syndrome. When 937 parents of children with Down syndrome were surveyed, over 95% of
t he respondents reported that their children had difficulty
being understood by people outside of their immediate
circle sometimes or frequently. Only approximately 5% of
parents...