Clinical Science, Intervention and
Technology, CLINTEC
Division of Speech and Language Pathology ___________________________________________________________________________________
Childhood Apraxia of Speech: a survey of knowledge and
experience in Swedish speech-language pathologists
Ann Malmenholt
Master thesis in Speech and Language Pathology
Autumn 2012
Supervisor: Anette Lohmander
2
Abstract Children with Childhood Apraxia of Speech (CAS) are seen by most clinical Speech-Language Pathologists (SLPs) working with speech and language disorders. The SLP’s understanding of CAS is crucial for diagnosis and treatment, yet little is known about their knowledge and experience. In a web-based questionnaire 178 Swedish SLPs answered questions about their perception of typical speech characteristics for CAS as potential diagnostic markers by grading their own assessment skills and estimating clinical prevalence and incidence. Eight top characteristics, from a list of 17 proposed typical speech characteristics, were listed by a mean of 66% of the SLPs in the survey (range 53-86%). These characteristics were: inconsistent production, motor-programming deficits, sequencing difficulties, oro-motor deficits, vowel errors, voicing errors, consonant cluster errors and prosodic disturbance. Eighty-one percent of the SLP’s followed Ozanne’s diagnostic model by recognizing several underlying deficits as markers for the diagnosis of CAS. The mode for clinical prevalence was 5 %. Fifty-two percent stated seeing between 0 and 1 new CAS-patient per year. Fifty-nine percent of SLP’s reported feeling confident assessing and diagnosing CAS, 41 % reported feeling unsure.
Keywords: Childhood Apraxia of Speech (CAS), survey, typical speech characteristics, diagnostic markers, clinical prevalence.
3
Introduction
Children with suspected Childhood Apraxia of Speech (CAS) are seen by clinical
Speech-Language Pathologists (SLPs) in Sweden as well as in many other parts
of the world. Defining criteria for this speech sound disorder continues to be
elusive, thus the search for valid and reliable diagnostic markers continues.
Different underlying defects in the fundamental processes preceding speech
production have been proposed. More recent studies have suggested
competence deficits in the area of phonemic representation ( e.g., Marquard,
Jacks & Davis, 2004; Nijland 2009) phonologic mapping (e.g., McNeill, Gillon, &
Dodd 2009) and motor programming (e.g.Marquard, Jacks & Davis, 2004;
Shriberg, Green, Campbell, McSweeny, & Scheer, 2003; Nijland, Maassen, van
der Meulen, Gabreels, Kraaimaat, & Schreuder, 2003b; Peter, & Stoel-Gammon,
2008). These suggested problem-areas may together be contributing factors
possibly explaining the deviant and divers speech production seen in children
with CAS.
The population of children with suspected CAS is limited, with reported
prevalence rates between 0.125 % to 1.3 % (Morley, 1972; Shriberg &
Kwiatkowski, 1994; Shriberg,
Aram & Kwiatkowski, 1997a). A considerably higher prevalence rate, 3,4 % to
4,3 %, was proposed by Delaney & Kent (2004) which may reflect the
difficulties to demarcate the diagnosis of CAS.
In 2002 ASHA formed an Ad Hoc Committee on Childhood Apraxia of Speech to
examine this area of practice. The technical report reviewing the research
background for CAS was completed in 2007 (ASHA, 2007a), supporting the
ASHA position statement published the same year (ASHA, 2007b). The report
led to e.g. a proposition for the definition of CAS and some consensus about
three features observed in children with suspected CAS in the literature a)
Inconsistent errors on consonants and vowels in repeated productions of
syllables or words, b) lengthened and disrupted co-articulatory transitions
between sounds and syllables, and c) inappropriate prosody, especially in the
realization of lexical or phrasal stress (p.2). Another ASHA recommendation
4
was to henceforth use the term CAS - Childhood Apraxia of Speech exclusively, a
term elsewhere referred to as Speech Delay – Apraxia of Speech (SD-AOS),
Developmental Verbal Dyspraxia (DVS), Developmental Apraxia of Speech
(DAS) or Developmental Verbal Dyspraxia (DVD).
In her general information website on CAS for Parents, Velleman states that
the”…disorder is more easily defined by what it is not
“(http://people.umass.edu/velleman/cas.html). This point was also made by
Hayden (1987) arguing that the group of children exhibiting speech motor
sequencing disruptions in its purest form is present in only a small number of
children, when excluding other sensory, cognitive and language disruptions
that could result in speech movement sequencing difficulties. The search for a
set of criteria for marking CAS, continues in both research and practice.
Velleman (2011) summarizes current knowledge in her statement that CAS is
“a disorder with motoric origins and cognitive-linguistic consequences” (p.85).
One great difficulty concerning CAS research is the uncertainty whether studies
have examined the correct population, displaying core difficulties of CAS or
difficulties also seen in children with other forms of childhood speech sound
disorders.
Aiming at defining a framework for research on speech sound disorders, seven
subtypes were listed in the Speech Disorders Classification Systems- Etiology
(SDCS-E), presented by Shriberg (2010); Speech Delay- Genetic, Speech Delay-
Otitis Media with Effusion, Speech Delay-Developmental Psychosocial
Involvement, Speech Delay-Apraxia of Speech, Speech Delay-Dysarthria, Speech
Errors – Sibilants and Speech Errors - Rhotics. Shriberg’s framework focused on
typology, etiology and the impact on speech processing. The author stated that
children with CAS often are reported to have a limited amount of speech in their
case history, a behavior not typically seen in the other subtypes. They are late to
begin to talk and show deficits in praxis marked by excessive articulatory
efforts when imitating speech models in spontaneous speech.
5
Several studies have investigated observations regarding key characteristics for
CAS by SLPs and parents. In a study by Forrest (2003) 75 SLPs were asked to
name up to three characteristics that they felt were necessary for a diagnosis of
DAS (henceforth referred to as CAS). Altogether 50 different characteristics
were listed and analyzed, resulting in the six most frequent criteria accounting
for 51,5% of all responses: inconsistent productions, general oro-motor
difficulties, groping, inability to imitate sounds, increased errors with increased
length, and poor sequencing of sounds.
Nijland (2009) listed the six most pronounced CAS speech characteristics
stated by treating SLP’s. The characteristics were: difficulty sequencing
articulatory movements, highly unintelligible speech, groping behavior,
suprasegmental disturbances, inconsistent speech errors and articulation
errors, in large similar to the top six characteristic reported by Forrest (2003)
but using a somewhat different terminology.
In a questionnaire asking 98 SLP’s about their clinical practice concerning
children with phonological problems the authors received information not
asked for about uncertainty in differential diagnosing children with suspected
DVD (henceforth referred to as CAS) from 54 (61%) of the answering SLPs
(Joffe & Pring, 2008). Their responses featured inconsistent production, oro-
motor problems, groping, sequencing problems, difficulty in copying sounds,
distortions of vowels and a history of feeding and drinking problems as
potential markers for CAS. Slow progress in therapy and resistance to therapy
were mentioned to be behaviors not typically seen in children with
phonological delay or disorder thus indicating CAS. In a parental survey, 201
parents of children with CAS were asked to evaluate functional characteristics
from the International Classification of Functioning, Disability, and Health –
Children and Youth version (ICF-CY), covering the disorders consequences in
daily life and the effects on medical, developmental and functional behaviors
(Teverovsky, Bickel, & Feldman, 2009). From the survey, functional
characteristics were clustered into four main factors: cognitive and learning
problems, social communication difficulties, behavioral dysregulation and other
6
oral motor problems. Identifying these often co-existing problem areas could
contribute to the understanding of underlying neural dysfunction.
Ozanne (1995) followed up a claim by Guyette and Diedrich in 1981, suggesting
that characteristics of CAS are commonly seen in all children displaying any
speech disorder of unknown origin. She studied 100 children with speech
disorders of unknown origin benchmarking previously mentioned motor
planning or programming problems (Rosenbek & Wertz, 1972; Adams, 1990;
Pollock & Hall, 1991). A cluster analysis of the 18 behaviors, thought to reflect
an underlying motor-programming or motor-planning disorder, showed that
between 27-38 % exhibited difficulties with diadochokinetic tasks, had
increased errors with increased load and inconsistent productions indicating
that these characteristics are not specific for CAS alone. In a study on normal
development of speech motor control boys were less mature up to the age of 5
years (Smith & Zelaznik, 2004). The authors also observed a plateau in the
development of coordination skills between the ages of 7-12, with consistency
increasing also after 12 years of age, an important indication of the complexity
of speech motor development. The influence of increased utterance length and
complexity on speech motor performance in typically developing children (5-
year-olds) and adults has been found to result in increased errors in both
children and adults. (Maner, Smith & Grayson, 2000). This can be seen as a
support for Ozanne’s suggestion to exclude difficulties with diadochokinetic
tasks, increased errors with increased load and inconsistent productions as
diagnostic markers for CAS.
“The Ozanne diagnostic model” refers to four clusters assembling a speech-
output planning and programming model. It contains three levels: phonological
planning (cluster I), phonetic programming (cluster II-IV) and oro-motor
control (cluster II-IV). To be diagnosed with the disorder of Childhood Apraxia
of Speech, children should display deficits on all three levels.
CAS, being a rare disorder, without consensus neither on clinical, diagnostic
markers nor a straightforward body of systematic research, leaves the clinical
7
SLPs puzzled. Despite the lack of fundamental consensus, SLPs assess and treat
patients with suspected CAS, constructing their own clinical understanding of
the disorder. Expanded information on the current knowledge and practice of
SLPs assessing and treating children with CAS would be valuable in order to
confirm or contradict anecdotal reports.
Aim
The aim of this paper was to survey Swedish SLPs level of knowledge and
experience about CAS. Research questions were:
How do SLPs rate their praxis and knowledge on assessing and
diagnosing children with suspected CAS?
What speech characteristics and other deficits do SLPs consider typical
in children with suspected CAS?
How common are children with suspected CAS? Estimation of
prevalence and incidence in the clinical population.
Method
A survey-questionnaire was constructed, asking quantitative and qualitative
questions about the population of children displaying the speech sound
disorder of suspected CAS. Questions targeted the SLPs background (5 items),
clinical accustomedness and theoretical knowledge regarding CAS (12 items),
estimation of own competence regarding CAS (3 items) and questions
regarding estimated prevalence and incidence in their own clinic (2 items).
Seven questions are not accounted for in this paper due to their limited interest
for the international reader and another three questions review treatment of
CAS and will be reported elsewhere.
The questionnaire was tested in a web-based pilot study. Four, clinically and
academically experienced SLPs participated. Comments from the pilot study
concerned technical issues and choice of words and were changed in the final
version.
The web-based questionnaire was sent to 289 Swedish SLPs working with pre-
and primary school-aged children during June-November 2011 asking 22
8
questions (see Appendix). Email addresses were transmitted by the SLP’s head
of departments and participants from 19 of in total 21 Swedish counties
responded. The superior received one reminder if no email address lists of
SLP’s working with the targeted patient group had been provided. The
questionnaire was distributed to the listed SLPs using Google Docs Form to
ensure that answers remained anonymous.
To avoid confusion due to variations in terminology, a list of 17 characteristics
from the literature, was presented asking respondents to select as many as
suggested speech characteristics as they felt was appropriate in order to
answer the question of typical speech characteristics seen in CAS. The
distribution of these answers was ranked and categorized according to the
cluster analysis proposed by Ozanne (1995). The 17 characteristics also
included six characteristics co-occurring in children with CAS, but not included
in Ozanne’s model. These were grouped reflecting different areas of difficulties,
namely deficits in language, attention and learning skills and difficulties with
motor control.
Questions 16 and 17 asked for SLPs preconceived opinions and thoughts shared
in free space answers. The concluding summaries of these answers are more
qualitative and were processed using content analysis.
The scale used in the question on how confident SLP’s felt assessing children
with CAS (Question 20) had six scale steps, ranging from very confident to very
unsure. By simplifying the answers into a dichotomous variable
(confident/unsure) the result became straightforward.
Results
One hundred-seventy-eight clinical SLPs responded, which equals a survey
response rate of 62%. Not all questions were answered by all respondents. The
9
response rate (RR) varied between different questions in the survey with a
mean-value of 87 %.
Respondents were from different clinical settings across Sweden and had a
range of clinical experience. Forty-one percent of respondents were in their
first five years of practice, 22 % had from five to ten years experience and 37%
percent more than ten years of clinical experience with preschool and primary-
school children (Question 9; RR=98%). Forty-four percent of the SLPs worked
at hospitals or public speech and language clinics, 12 % worked at university
hospitals, 24 % at habilitation centers, nine percent in special pre- and primary
schools for children with speech- and language disorders, eight percent at
private clinics and three percent in other working places (Question 4;
RR=97%).
Praxis and knowledge on assessment and diagnosis Six main assessment approaches emerged when analyzing respondents’
answers in their own words about what they considered important when
assessing children with suspected CAS (Question 17; RR=74%). The most
frequently mentioned approach (42%) was a formal perceptual analysis of the
child’s speech in combination with an oro-motor assessment, see Figure 1.
The ICD-10 diagnoses most frequently used (Question 10; RR=96%) were oral
and/or verbal apraxia (R48.2) occurring in 44 %, phonological disorder
(F80.0A) in 22 %, a combination of phonological disorder and oral motor
developmental delay (F80.0A + F80.0B) in 23 % and other ICD-10 codes in 11
% of answers.
10
Figure 1: Different assessment approaches for CAS reported by Swedish SLPs (n=131).
Twenty-nine percent of the SLPs perceived CAS to be a disorder in its own right,
10 % considered the disorder to be part of or in co morbidity with another
disorder, 51 % of the SLPs experienced that some cases are clear CAS and some
are part of or in co morbidity with other disorders. The alternative: “CAS is a
consequence of another disorder” was not agreed upon by any SLP but 10 %
replied that they did not know (Question 13; RR=96%).
When asked to share observations of co-occurring difficulties seen in children
with CAS (Question 16; RR=38%) different issues were raised by respondents
using the free text answering space. Most answers were clarifications and
comments on issues covered in general, often using different terminology, in
listed typical characteristics (Question 17) and statements about typical
behaviors (Question 15). The notion of fluctuations in the ability to produce
speech during different days was added. Some SLPs observed additional co
ordination difficulties not only obstructing smoothness of articulators and body
Formal perceptual
analysis + oro-motor
assessment (42%)
Formal oro-motor
assessment (5%)
Referring patient to specialized SLPs for oro-motor assessment (11%)
Assessment of language skills
(15%)
Language and oro-motor assessment
(18%)
Own clinical assessment battery (9%)
Assessment approaches
11
movements but also affecting the control of air flow, resulting in voice quality
issues.
When asked to rate their own ability as SLPs to assess children with suspected
CAS on a six scale-step scale 55 % of respondents felt unsure and 45 %
confident about diagnosing CAS (Question 20; RR=97%). A further analysis of
these figures was conducted based on the fact that only half of the SLPs
reported that they do assess and diagnose CAS (Question 10; RR=96%). It
revealed that out of the SLPs, not assigned to diagnose children with suspected
CAS, 29 % felt confident about performing CAS assessment and 71 % did not.
Among the SLPs that assessed and diagnosed CAS 59 % reported that they felt
confident and 41 % that they felt unsure.
Speech characteristics and behaviors seen in CAS
The 171 respondents selected 2-17 characteristics from a list of 17
characteristics (Question 14; RR=96%); Mode was 7.2, in total 1043 selected
characteristics. The answers were assembled in a matrix, grouped in clusters
according to Ozanne’s model (1995), see Table 1.
12
Table 1: Typical characteristics of CAS in rank order from a SLP survey and categorized according to the cluster analysis proposed by Ozanne (1995).
Typical characteristics in CAS Frequency of selection of characteristics
Cluster analysis according to Ozanne (1995)
Inconsistent production 85% I
Motor-programming deficits 82% III
Sequencing difficulties 71% II
Oro-motor deficits 63% II
Vowel errors 62% I
Voicing errors 61% II
Consonant cluster deletion 54% III
Prosodic disturbance 53% IV
Phonological deficits 44%
Resonance inconsistency 36% II
Poor fine-motor skills 34%
Metathesis 23% III
Suprasegmental disturbance 19% IV
Poor gross-motor skills 12%
Language impairment 10%
Learning difficulties 5%
Attention deficits 4%
Eighty-one percent of SLPs listed typical characteristics of speech in children
with CAS representing features from all three clusters I-III, see Figure 2.
Similar distribution was found for clusters I, II and III respectively, whereas
characteristics in cluster IV were registered somewhat less frequent.
The six characteristics not included in Ozanne’s model, were grouped in four
areas of difficulties, showing that almost half of the answering SLPs
acknowledge CAS patients to display language impairment as well. Motor
difficulties, i.e. poor fine and gross motor skills, were noted by one third of the
SLPs to be a typical characteristic displayed by children with suspected CAS.
Learning difficulties and attention deficits were not reported to be typically co-
occurring.
13
Figure 2.The 17 speech characteristics typical for CAS clustered using Ozanne’s model (1995) supplemented with typical co-occurring characteristics in subsets of CAS.
Statements about suggested, typical behaviors seen in children with CAS had to
be completed by the respondents (Question 15; RR=96%). In total 92 % shared
the opinion that “children with CAS make very slow progress” and 58 % felt
that “patients were resistant to therapy”. “Regressing after a treatment brake”
was an experience shared by 58 % and “persistent speech difficulties at school
age” was noted by 84 % of the SLPs. “Difficulties with reading development”
was observed by 24 % and “difficulties with writing development” by 23 % of
the SLPs.
Clinical prevalence and incidence
The mode for rated clinical prevalence was 5 % over all clinical settings in this
study (Question 12; RR=82%), range from 0-70 % (see figure 3) reflecting the
SLP’s varying patient populations depending on work settings. Thus, the mode-
90% 96% 91%
78% 81%
53% 46%
36%
5% 4%
Clustered Characteristics in CAS
14
value for prevalence estimated by SLPs working at habilitation centers was
twice as high (11%).
Figure 3: Estimation of clinical prevalence of CAS by answering SLP’s
About half of the SLPS (52 %) stated seeing between 0 and 1 new patient with
suspected CAS per year in their clinic (Table 2).
Table 2: The clinical incidence of CAS estimated by SLP’s showing the rate at which new cases occur on their caseload during one year (Question 11; RR=89%).
Number new CAS patients/year
0 0.5 1 2 3 4 5 7 8 10 12 13 15 20
% Answering SLPs
2 20 30 16 11 3 4 2 2 4 1 1 3 1
Discussion
In this study broad information about clinical SLPs knowledge and experience
concerning children with suspected CAS was collected. The quantity and
distribution of SLP’s throughout the country and in different working settings
makes it likely that they together represent current clinical practice in Sweden.
We are assuming this, despite the lack of answers from two counties and lack of
data on the distribution of SLP’s working in different work settings.
The drawback to distributing the survey anonymously was that it ruled out the
possibility to remind the SLPs to participate.
2 13 7 6 2
30
4 11 1 5 11
2 3 2 1 0 1 2 3 4 5 7 10 13
15 20 25
30
50
70 Answering SLPs in % Prevalence %
15
Praxis and knowledge on assessment and diagnosis
Assessment approaches differed, reflecting the absence of a reliable and specific
test for CAS in Sweden. At present SLP’s administer their own test batteries
which probably reflect their view of CAS as a disorder of primarily
phonologic/linguistic and/or motor difficulty. The same disparity is seen in the
reported ICD-10 diagnoses used, corresponding to the SLPs comprehension and
theoretical knowledge of the disorder. This probably reflects differences in SLP-
education in the field of motor speech disorders and, particular, CAS during the
past decades.
Another challenge is diagnosing children with milder symptoms, where
suspected CAS is to be differentiated from delays in phonologic development
and/or oro-motor control, a combination of diagnoses used by almost one-
fourth (23%) in this study. Perhaps the less alarming diagnose of speech- and
oro-motor delay is preferred by SLPs in milder cases of suspected CAS due to
the implications of a neurologically based diagnosis? Age is another factor
influencing and changing the manifestations of CAS in different children over
time.
About one third of SLPs in this survey viewed CAS as a defined, exclusive
disorder, but 10 % had not experienced clear cut cases of CAS. On the other
hand half of the SLPs reported that there were clear cut cases but also others,
where CAS symptoms appeared to be a part of or in co morbidity with other
disorders. This diversity of clinical experience and viewpoints on CAS reflect
the multi facetted character of the disorder and the influence of work settings
and experience.
Thanks to the anonymity sincere answers are presumed. A future challenge is
to address the 41 % of the SLPs, who assess and diagnose children with
suspected CAS, but clearly state the need for different educational measures.
One obstacle to increase clinical skills is the limited number of patients with
suspected CAS for SLPs to get experience from. This could be resolved through
16
specialization of SLPs with a recognized competence in motor speech disorders,
a suggestion already made in ASHAs position statement (2007b).
Speech characteristics and behaviors seen in CAS
The ranking of typical speech characteristics in CAS without clustering in this
survey corresponded in large with other surveys (Forrest, 2003; Joffe & Pring,
2008; Nijland, 2009).
Forrest (2003) concluded that her study on diagnostic criteria was limited due
to predetermined instructions (i.e. provide up to three criteria for diagnosing
CAS). In this study the limitation was in the list of predetermined typical
characteristics for CAS (i.e. the SLPs could not specify in their own words) yet
the mode for the number of chosen characteristics was over seven, close to the
number repeatedly stated in other surveys. In this study, more than 50 % of the
SLPs listed as many as eight characteristics, with inconsistent production being
the most common (85%), also mentioned as a key feature by Rosenbek and
Wertz (1972) among others. Motor-programming deficits (82%) described as
lack of automatization of speech motor movements (i.e. a global term including
groping and voluntary vs. involuntary speech movements) (e.g., Rosenbek &
Wertz 1972; Pollack & Hall, 1991) is a feature difficult to capture in one term.
Sequencing difficulties (71%) (e.g., Rosenbek & Wertz, 1972), oro-motor
deficits (63%) (e.g., Adams, 1990; Pollack & Hall, 1991; Rosenbek & Wertz,
1972) vowel errors (62%) (e.g., Rosenbek & Wertz, 1972; Pollock & Hall,
1991), voicing errors (61%) (e.g. Yoss & Darley, 1974a), consonant cluster
deletion (54%) (e.g., Rosenbek & Wertz, 1972; Yoss & Darley, 1974a) and
prosodic disturbance (53%) (e.g., Rosenbek & Wertz, 1972; Pollack & Hall,
1991) are difficulties alerting SLP’s.
During the construction of the survey no weighting of speech characteristics
was performed. However in the analysis the 17 characteristics were distributed
into Ozannes IV clusters which resulted in similar frequencies (90-96%) for
clusters I to III. Cluster IV showed a somewhat lower frequency (78%),
17
probably because cluster IV consists of only two characteristics, one being
deviant prosody and the other an anamnesis feature not asked for in this
survey, which was no history of babbling.
Other functional problems in children with clinically diagnosed CAS were listed
using the ICF-CY and focusing on problems in addition to communication
difficulties based on specific speech output (Teverovsky, Bickel & Feldman,
2009). For over half of the children with CAS in that study, parents reported
health, mental health and developmental conditions. A significant proportion of
children with CAS had involvement of other factors in both genetic and
environmental domains (Shriberg 2010). Future research in CAS would
therefore benefit from thorough descriptions of the subjects.
Clinical prevalence and incidence
The estimated clinical prevalence mode-value of 5 % reflects different work
settings, given that the highest, outlying estimates (50% and 70%) came from
clinicians working at habilitation centers. The variance of reported prevalence’s
in the literature, from 0,125% to 3,4%, (Delaney & Kent, 2004; Morley, 1972;
Shriberg & Kwiatkowski, 1994; Shriberg, Aram, & Kwiatkowski, 1997) raises
questions about descriptions and inclusion criteria in research studies and
possibly also limitations in agreement about the group of patients diagnosed
with CAS.
Clinical incidence was asked for in percent. A few SLPs misunderstood and
supplied a rough estimate of the work life total number of patients. In these
cases the percent figure was calculated, dividing the stated sum of patients
encountered with the reported years of experience as SLP seeing patients with
CAS. The overall low incidence reminds us of that CAS occupies a small portion
of the SLPs caseload; involving around half of the clinical SLPs. This in turn may
lead to a lack of confidence and knowledge within the professional society.
18
Conclusion
Even though the majority (89%) of SLPs stated a need for further education
about CAS (Question 22), this study reveals that many SLPs (81%) have god
clinical skills and are alerted when several typical speech characteristics for
CAS are present in a patient. A promising finding considering that researchers
often rely on experienced clinicians for referrals of children with suspected CAS
as potential candidates for research populations. In the body of CAS literature
much effort is spent on finding diagnostic markers in order to specify the
diagnosis of CAS and distinguishing it from other subsets of speech sound
disorders (e.g., Shriberg, Aram, & Kwiatkowski, 1997b + 1997c; Velleman &
Shriberg, 1999). However, a cluster of diagnostic markers might be more
appropriate in order to differentiate these children from children with other
speech disorders.
The survey-question with lowest RR (Question 16; RR=38%) was about
observations made on co-occurring difficulties in children with CAS, asking
beyond earlier questions. Few new topics were raised given the opportunity to
answer in own words. This might positively reflect the broadness of the survey
or it could be due to the fact that this is an open question in the latter part of the
questionnaire and respondents were eager to conclude.
Using the term syndrome together with CAS might signal that the disorder has
several characteristics. Love (2000) considered descriptions of syndromes in
neurologic medicine and concluded considering CAS that “This motor
programming disability may or may not result in a rigidly consistent set of
motor, phonologic, linguistic, or neurologic signs or symptoms, and
inconsistency among symptoms should be expected as typical rather than
atypical.” (p. 92). Childhood apraxia of speech is widely agreed upon to be a
disorder of motor planning and/or motor programming. (e.g., Caruso &
Strand,1999; Hayden, 1994; Ozanne, 1995).
The Ozanne model of speech-output planning and programming could provide
a possible guideline for clinical SLP’s. While assessing children with suspected
19
CAS it could be possible to cluster the overt speech characteristics reflecting
underlying deficits. Varying characteristics could still meet up to a diagnosis of
CAS if difficulties are simultaneously found in all three domains proposed by
Ozanne.
The results from this survey supports earlier findings, i.e. inconsistent
production being described as the most prominent characteristic in CAS
mentioned by 85% of the SLPs. Seven other characteristics were listed by more
than 53% of all respondents.
There was a massive agreement found among SLPs regarding clusters of typical
speech characteristics seen in CAS patients.
In future research on children with suspected CAS, an approach as supposed by
Ozanne, could reduce procedural limitations and increase validity, making
inclusion criteria of the studied population transparent and comparable, a work
started by e.g. Moriarty & Gillon (2006) and McNeill, Gillon & Dodd (2009).
Acknowledgments
This study was completed as a master’s thesis by the first author. We are
grateful to all colleagues, answering the survey and sharing their clinical
experience and showing interest in this work.
Declaration of interest: The authors report no conflicts of interest. The authors
alone are responsible for the content and writing of the paper.
References Adams, C. (1990). Syntactic comprehension in children with expressive language impairment. British Journal of Disorders of Communication, 25(2), 149-171. American Speech-Language-Hearing Association (2007a). Childhood Apraxia of Speech: [Technical Report] Ad Hoc Committee on Apraxia of Speech in Children, Rockville Pike, MD:ASHA. American Speech-Language-Hearing Association (2007b). Childhood apraxia of speech [Position Statement]. Available from www.asha.org/policy. Caruso, A,. & Strand, E. (Eds.) (1999). Clinical Management of Motor Speech
Disorders in Children. New York: Thieme. Delaney, A. L., & Kent, R.D. (2004). Developmental profiles of children
diagnosed with apraxia of speech. Poster session presented at the annual
20
convention of the American-Speech-Language-Hearing Association, Philadelphia.
Forrest, K. (2003). Diagnostic criteria of developmental apraxia of speech used by clinical speech-language pathologists. American Journal of Speech-Language Pathology, 12(3), 376-380.
Google Docs Form (June 2011) [Internet] https://docs.google.com Guyette, T., & Diedrich, W. (1981). A critical review of developmental apraxia of
speech. In N. Lass (Ed.), Speech and Language: Advances in Basic Research and Practice (pp. 1-49). New York: Academic Press
Hayden, D. A. (1994). Differential diagnosis of motor speech dysfunction in children. Clinics in Communication Disorders, 4(2), 119-141.
Hayden, A., & Square, P. (1999). VMPAC, Verbal Motor Production Assessment for Children. San Antonio, TX: The Psychological Corporation.
Joffe, V., & Pring, T. (2008). Children with phonological problems: a survey of clinical practice. International Journal of Language & Communication Disorders, 43(2), 154-164.
Love, R.J. (2000). In R.J. Love (Ed.), Childhood Motor Speech Disabability. (pp.89-92). (2nd ed.) Needham Heights, MA: Allyn and Bacon
Maner, K. J., Smith, A., & Grayson, L. (2000). Influences of utterance length and complexity on speech motor performance in children and adults. Journal of Speech, Language, and Hearing Research, 43(2), 560-573.
Marquardt, T. P., Jacks, A., & Davis, B. L. (2004). Token-to-token variability in developmental apraxia of speech: three longitudinal case studies. Clinical Linguistics & Phonetics, 18(2), 127-144.
McNeill, B. C., Gillon, G. T., & Dodd, B. (2009). Phonological awareness and early reading development in childhood apraxia of speech (CAS). International Journal of Language & Communication Disorders, 44(2), 175-192.
Morley, M. E. (1972). The development and disorders of speech in childhood (1st ed.). London: Livingstone.
Moriarty, B. C., & Gillon, G. T. (2006). Phonological awareness intervention for children with childhood apraxia of speech. International Journal of Language & Communication Disorders, 41(6), 713-734.
Nijland, L. (2009). Speech perception in children with speech output disorders. Clinical Linguistics & Phonetics, 23(3), 222-239.
Nijland, L., Maassen, B., Van Der Meulen, S., Gabreels, F., Kraaimaat, F. W., & Schreuder, R. (2003). Planning of syllables in children with developmental apraxia of speech. Clinical Linguistics & Phonetics, 17(1), 1-24.
Ozanne, A. (1995) (2005). Childhood apraxia of speech. In B. Dodd (Ed.), Differential Diagnosis and Treatment of Children with Speech Disorder. (pp. 71-82). (2nd ed.) London and Philadelphia: Whurr Publishers.
Peter, B., & Stoel-Gammon, C. (2008). Central timing deficits in subtypes of primary speech disorders. Clinical Linguistics & Phonetics, 22(3), 171-198.
21
Pollack, K., & Hall, P. (1991). An analysis of vowel misarticulations of five children with developmental apraxia of speech. Clinical Linguistics & Phonetics 5: 207-24.
Rosenbek, J., & Wertz, R. (1972). A review of 50 cases of developmental apraxia of speech. Language, Speech and Hearing Services in Schools 3: 23-33. Shriberg, L.D. (2010). Childhood Speech Sound Disorders: From Postbehaviorism to the Postgenomic Era. In Paul & Flipsen (Eds.), Speech Sound Disorders in Children. (pp. 1-33). San Diego, CA: Plural Publishing Shriberg, L. D., & Kwiatkowski, J. (1994). Developmental phonological
disorders. I: A clinical profile. Journal of Speech, Language, and Hearing Research, 37(5), 1100-1126.
Shriberg, L.D., Aram, D.M., & Kwiatkowski, J. (1997a). Developmental apraxia of speech: I. Descriptive and theoretical perspectives. Journal of Speech, Language, and Hearing Research, 40, 273-285.
Shriberg, L. D., Aram, D. M., & Kwiatkowski, J. (1997b). Developmental apraxia of speech: II. Toward a diagnostic marker. Journal of Speech, Language, and Hearing Research, 40(2), 286-312.
Shriberg, L.D., Aram, D.M., & Kwiatkowski, J. (1997c). Developmental apraxia of sepech: III. A subtype marked by inappropriate stress. Journal of Speech, Languag, and Hearomg Research, 40, 313-337.
Shriberg, L. D., Green, J. R., Campbell, T. F., McSweeny, J. L., & Scheer, A. R. (2003). A diagnostic marker for childhood apraxia of speech: the coefficient of variation ratio. Clinical Linguistics & Phonetics, 17(7), 575-595.
Smith, A., & Zelaznik, H. N. (2004). Development of functional synergies for speech motor coordination in childhood and adolescence. Developmental Psychobiology, 45(1), 22-33.
Teverovsky, E. G., Bickel, J. O., & Feldman, H. M. (2009). Functional characteristics of children diagnosed with Childhood Apraxia of Speech. Disability and Rehabilitation, 31(2), 94-102.
Velleman, S. L. (2011). Lexical and phonological development in children with childhood apraxia of speech--a commentary on Stoel-Gammon's 'Relationships between lexical and phonological development in young children. Journal of Child Language, 38(1), 82-86.
Velleman, S. L., & Shriberg, L. D. (1999). Metrical analysis of the speech of children with suspected developmental apraxia of speech. Journal of Speech, Language, and Hearing Research, 42(6), 1444-1460.
Velleman, S.L. General Information for Parents about Childhood Apraxia of Speech (May 2012) on Shelley L. Velleman’s home page [Internet] http://people.umass.edu/velleman/cas.html
World Health Organization, ICF-Children and Youth Version. World Health Organization [Internet] http://apps.who.int/classifications/icfbrowser/
Yoss, K.A., & Darley, F.L. (1974a). Developmental apraxia of speech in children. Journal of Speech and Hearing Research, 17, 399-416.
22
Appendix Survey-questions:
1. Where did you study to become a Speech Language Pathologist?
2. Which year did you graduate?
3. Which county are you working in?
4. What type of setting are you working in?
Hospital, university hospital, public speech and language clinic, private clinic, habilitation center, special pre- and primary school for children with speech and language disorders, other working places
5. How many SLP-colleagues seeing pre- and primary school patients do
you have at your setting?
6. Was there a lecture about CAS during your undergraduate studies?
7. Have you participated in lectures or courses after your undergraduate
studies?
8. Have you searched for information about CAS on your own?
9. For how long have you been working with pre- or primary school aged
children?
< 5 years, 5-10 years, 11-15 years, 16-20 years, >20 years 10. Do you assess and diagnose children with CAS? yes / no
If you do, what ICD-code do you use? (Choose one or multiple answers) F80.0A, F80.0A+F80.0B, R48.2, R48.2A, R48.2B, other
11. Approximately how many children displaying CAS have you met?
Space for free answer 12. Approximately how many percent of patients on your caseload do you
consider having difficulties with verbal praxis?
Space for free answer 13. I consider CAS to be…… (Choose one or multiple answers)
o a diagnosis of its own right, not necessarily coexisting with other
disorders
o part of or in co morbidity with other disorders such as SLI, ADHD,
ADD, dyslexia, Cerebral Palsy, Down’s syndrome, Rett’s syndrome
or other disorders
o as a consequence of other disorders
o I do not know
14. Typical symptoms for children displaying CAS are….. (Choose one or multiple
answers)
Inconsistent production, motor-programming deficits, sequencing difficulties, oro-motor deficits, vowel errors, voicing errors, consonant cluster deletion, prosodic disturbance, phonological deficits, resonance inconsistency, poor fine-
23
motor skills, metathesis, suprasegmental disturbance, poor gross-motor skills, language impairment, learning difficulties, attention deficits
15. Children with CAS... (Choose one or multiple answers)
make very slow progress, make expected progress, are during periods almost resistant to therapy, regress after treatment brake, have persistent speech difficulties at school age, have difficulties with reading development, have difficulties with writing development
16. Co-occurring difficulties you have observed in children with CAS?
Space for free answer 17. If a child is suspected of having CAS, what do you consider to be important
during assessment?
Space for free answer 18. What do you consider to be most important when treating children with
CAS?
19. If you have any experience treating children with CAS, please share
examples of successful intervention.
20. How secure do you feel assessing children with CAS?
Very confident, confident, fairly confident, fairly unsure, unsure, very unsure 21. How secure do you feel treating children with CAS?
22. Do you consider yourself lacking competence concerning CAS?
yes / no Questions 1-3, 5-8, 18, 19 and 21 are not accounted for in the present paper!