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From the DEPARTMENT OF CLINICAL SCIENCE,
INTERVENTION AND TECHNOLOGY, CLINTEC
Division of Speech and Language Pathology
Karolinska Institutet, Stockholm, Sweden
EXPLORING CHILDHOOD APRAXIA OF
SPEECH:
SPEECH AND LANGUAGE PROFILES IN
5-YEAR-OLDS WITH
SUSPECTED APRAXIA OF SPEECH
OR CLEFT PALATE
Ann Malmenholt
Stockholm 2020
Cover illustration by Ann Malmenholt
All previously published papers were reproduced with permission from the publisher.
Published by Karolinska Institutet.
Printed by Universitetsservice US-AB, Stockholm, Sweden
© Ann Malmenholt, 2020
ISBN 978-91-7831-761-5
Exploring childhood apraxia of speech:
Speech and language profiles in 5-year-olds with
suspected apraxia of speech or cleft palate
THESIS FOR DOCTORAL DEGREE (Ph.D.)
which, by due permission from Karolinska Institutet, will be publicly defended in lecture hall
Månen, Alfred Nobels Allé 8, Karolinska Institutet, Campus Flemingsberg
Friday, May 29th, 2020 at 9 a.m.
By
Ann Malmenholt
M.Sc., Speech and Language Pathologist
Principal Supervisor:
Associate Professor Per Östberg
Karolinska Institutet
Department of Clinical Science,
Intervention and Technology
Division of Speech and Language Pathology
Co-supervisors:
Professor Anette Lohmander
Karolinska Institutet
Department of Clinical Science,
Intervention and Technology
Division of Speech and Language Pathology
Associate Professor Anita McAllister
Karolinska Institutet
Department of Clinical Science,
Intervention and Technology
Division of Speech and Language Pathology
Opponent:
Dr Sara Wood, PhD
Queen Margaret University Edinburgh,
United Kingdom
Division of Speech and Hearing Sciences
Examination Board:
Associate Professor Margareta Dahl
Uppsala University
Department of Women’s and Children’s Health
Neuropediatrics/Pediatric Oncology
Associate Professor Christina Samuelsson
Linköping University
Department of Biomedical and Clinical Sciences
Division of Sensory Organs and Communication
Associate Professor Avni Abdiu
Linköping University
Department of Biomedical and Clinical Sciences
3
TABLE OF CONTENTS
ABSTRACT ............................................................................................................ 5
SAMMANFATTNING .......................................................................................... 6
LIST OF SCIENTIFIC PAPERS ........................................................................... 7
LIST OF ABBREVIATIONS ................................................................................ 8
1 INTRODUCTION ......................................................................................................... 9
1.1 GENERAL MOTIVATION ................................................................................... 9
1.2 CHILDHOOD APRAXIA OF SPEECH ............................................................. 10
1.2.1 Terminology ............................................................................................... 11
1.2.2 Classification .............................................................................................. 12
1.2.3 Speech characteristics ................................................................................ 14
1.2.4 Childhood apraxia of speech comorbidity ................................................. 16
1.3 CLEFT PALATE ± LIP ........................................................................................ 18
1.3.1 Speech characteristics ............................................................................... 19
1.3.2 Cleft palate ± lip comorbidity ................................................................... 21
2 AIMS ............................................................................................................................. 23
2.1 GENERAL AIMS ................................................................................................. 23
2.2 SPECIFIC AIMS ................................................................................................... 23
3 METHOD ..................................................................................................................... 24
3.1 PARTICIPANTS .................................................................................................. 24
3.2 MATERIAL .......................................................................................................... 26
3.2.1 Speech samples .......................................................................................... 26
3.2.2 Observations of orofacial function ............................................................ 26
3.2.3 Language samples ...................................................................................... 26
3.2.4 Questionnaires ............................................................................................ 27
3.2.4.1 SLP questionnaires ....................................................................... 27
3.2.4.2 Parental questionnaires ................................................................ 27
3.2.5 Audio and video recordings ...................................................................... 27
3.3 ANALYSIS ........................................................................................................... 27
3.3.1 Measures of speech .................................................................................... 28
3.3.1.1 Articulation.................................................................................... 28
3.3.1.2 Childhood apraxia of speech ........................................................ 29
3.3.1.3 Intelligibility .................................................................................. 29
3.3.2 Measures of orofacial function .................................................................. 29
3.3.3 Measures of language................................................................................. 29
3.3.4 Measures of communication ...................................................................... 30
3.4 RELIABILITY ...................................................................................................... 30
3.5 STATISTICAL ANALYSIS ................................................................................ 31
3.6 ETHICAL APPROVALS ..................................................................................... 31
4
4 RESULTS ..................................................................................................................... 32
4.1 Study I ................................................................................................................... 32
4.2 Study II .................................................................................................................. 32
4.3 Study III ................................................................................................................. 33
4.4 Study IV................................................................................................................. 33
5 DISCUSSION .............................................................................................................. 34
5.1 A SPEECH PROFILE ASSOCIATED WITH CHILDHOOD APRAXIA
OF SPEECH ................................................................................................................. 34
5.2 A LANGUAGE PROFILE ASSOCIATED WITH CHILDHOOD
APRAXIA OF SPEECH ......................................................................................... 37
5.3 FUNCTIONAL COMMUNICATION ASSOCIATED WITH
SEVERELY DISORDERED SPEECH ................................................................... 39
5.4 EXPLANATORY FACTORS FOR SPEECH OUTCOMES IN
CHILDREN WITH CLEFT PALATE ± LIP .......................................................... 40
5.5 METHODOLOGICAL CONSIDERATIONS................................................ 41
5.5.1 Participants ........................................................................................... 41
5.5.2 Perceptual assessment and analysis ..................................................... 41
5.5.3 Diagnostic procedure ........................................................................... 42
6 CONCLUSIONS .................................................................................................... 43
7 CLINICAL IMPLICATIONS............................................................................... 44
8 FUTURE STUDIES ............................................................................................... 46
9 ACKNOWLEDGEMENTS ................................................................................... 47
10 REFERENCES ....................................................................................................... 49
5
ABSTRACT
Introduction and aims: Childhood apraxia of speech (CAS) is a speech sound disorder (SSD)
lacking a quantifiable measure discriminating all cases of CAS from other SSDs. This project aimed
at exploring CAS using different perspectives when examining speech and language difficulties
commonly seen in 5-year-old children with suspected CAS or children with repaired cleft palate
(CP±L). Children with CP±L were added to broaden and differentiate the knowledge base on CAS
and to search for factors explaining unfavorable speech outcome in this group.
Material and methods: In study I, a questionnaire was constructed and used, anonymously
surveying Swedish SLPs (n=178) knowledge and praxis about CAS features and assessment.
Findings were compared to earlier survey findings from English contexts. Study II examined
articulation proficiency and orofacial function of children with CP±L (n=52) based on SLP
examination and parental interview. For measurement of intelligibility, both parent reports and SLP
ratings were compared. Study III included children with CP±L and disordered speech (n=19) and
children with suspected CAS (n=15). Phonetic transcription and CAS diagnostics were based on
audio-recordings of single word naming. The diagnosis was built on judgement of presence or
absence of speech features using a checklist constructed for English speakers. The cross-linguistic
applicability of the operationalized features and checklist was tested. In study IV language
competence of children with CAS and CP±L was directly assessed, and parental ratings of everyday
life communication were added, and results compared.
Results: Swedish SLP’s views on typical speech characteristic of CAS, surveyed in study I,
corresponded in large with reports of SLP’s from English-speaking contexts. The top seven
characteristics were inconsistent speech production, sequencing difficulties, oro-motor deficits,
vowel errors, voicing errors, consonant cluster deletion and prosodic disturbance. In study II, 37%
of children with CP±L were found to have orofacial dysfunction; however, this was not an
explanatory factor for speech outcome for these children. A distinct CAS profile, found in study
III, included the five features: phonemic speech inconsistency for consonants and vowels plus
vowel error, voicing error, difficulty achieving initial articulatory configurations or transitionary
movement gestures and stress errors. In study IV, expressive language disorder was found in 67%
of children with CAS. Receptive language ability was significantly better than expressive language
in all children with CAS. No such difference was observed in the group of children without CAS
(non-CAS SSD). Parent ratings of communication skills reflected an increased burden on
communication in everyday life when difficulties within both speech and language domains were
present.
Conclusions: Despite relevant theoretical and/or clinical knowledge about CAS, Swedish SLPs
reported a need for further education. Swedish-speaking 5-year-olds with CAS shared a distinct
speech profile including five features, with prosodic impairment almost exclusively seen in children
with CAS. Findings supported cross-linguistic applicability of CAS speech feature
operationalization between English and Swedish speakers. In children with CP±L and SSD, a
heightened cooccurrence of CAS, compared to clinical prevalence, should be anticipated.
Expressive language ability in children with CAS was worse than receptive language ability. Poor
articulation proficiency in children with CP±L did not correlate with orofacial dysfunction. Parental
ratings of communication abilities in everyday life added ecological validity and confirmed validity
of the clinical assessment procedures.
6
SAMMANFATTNING
Introduktion och syfte: Taldyspraxi (TD) är en talstörning som är svår att diagnostisera eftersom det
saknas ett kvantifierbart mått som särskiljer alla barn med TD från barn med andra typer av talstörningar.
Syftet med detta projekt var att utforska tal- och språkförmågan hos 5-åringar med TD och hos barn
med gomspalt. Barnen med gomspalt inkluderades för att bredda och nyansera kunskapen om TD men
också för att söka efter faktorer som kan förklara kvarstående talstörning hos en andel 5-åringar
behandlade för gomspalt.
Material och metoder: I studie I utvecklades en enkät med frågor kring kunskap och praxis gällande
särdrag och undersökning av TD som besvarades anonymt av svenska barnlogopeder (n=178). Svaren
jämfördes med tidigare enkätstudiesvar av logopeder i engelskspråkiga kontexter. I studie II
undersöktes tal och orofacial funktion hos 52 barn med gomspalt, direkt av logoped och indirekt genom
frågor till barnets föräldrar, talförståelighet skattades av både logoped och föräldrar och skattningarna
jämfördes. I studie III deltog 19 barn med gomspalt och talstörning samt 15 barn med förmodad TD.
Talet spelades in vid bildbenämning samt transkriberades. TD-diagnosen byggde på logopedbedömning
av olika särdrag i talet, utifrån en checklista utformad för engelskspråkiga barn. Checklistan och
validiteten i beskrivningen av särdragen undersöktes avseende användning på svenska. I studie IV
undersökte logoped den språkliga förmågan hos barn med TD eller gomspalt och
kommunikationsförmågan i det dagliga livet skattades av föräldrarna, varefter resultaten jämfördes.
Resultat: Svenska logopeders kunskap om typiska särdrag i talet hos barn med TD, som undersöktes i
studie I, överensstämde i stort med engelskspråkiga logopeders. De sju mest frekvent rapporterade
dragen var inkonsekvent tal, svårigheter med sekvensering av talljud, oralmotoriska svårigheter,
vokalfel, svårigheter med distinktionen tonande-tonlös, förenklingar av konsonantkluster samt
avvikande prosodi. I studie II uppvisade 37 % av barnen med gomspalt en orofacial dysfunktion, som
dock inte förklarade barnens talstörning. I studie III framkom en särskild TD-profil med fem särdrag:
inkonsekvent uttal av konsonanter och vokaler samt vokalfel, svårigheter med distinktionen tonande-
tonlös, svårigheter att hitta artikulatorisk rörelse för ordstart och koartikulation mellan språkljud samt
avvikande prosodi. Expressiv språkstörning konstaterades hos 67 % av barnen med TD i studie IV.
Språkprofilen, med en signifikant bättre receptiv än expressiv förmåga, sågs enbart hos barn med TD.
Föräldraskattningen av kommunikationsförmågan i det dagliga livet pekade på större svårigheter för
barn med både tal- och språkstörning.
Slutsatser: Trots relevant teoretisk/klinisk kunskap om TD uppgav de flesta svenska barnlogopeder ett
utbildningsbehov. En specifik talprofil hos svensktalande femåringar med TD framkom. Talprofilen
bestod av fem talkarakteristika och inkluderade prosodiska svårigheter noterades i princip uteslutande
hos barn med TD. Resultaten stödjer användningen av beskrivna och operationaliserade
talkaraktäristika för engelsktalande barn också för svensktalande barn. Hos barn med gomspalt och
talstörning borde en högre andel barn förväntas ha TD, jämfört med kliniska prevalensuppgifter.
Expressiv språkförmåga hos barn med TD var generellt sämre än receptiv förmåga. Avvikande
artikulationsförmåga hos barn med gomspalt förklarades inte av orofacial dysfunktion.
Föräldraskattningar av vardaglig kommunikationsförmåga visade att det fanns större svårigheter hos
barn med både tal- och språkstörning. Dessa föräldraskattningar tillförde information om
kommunikationsförmågan i det dagliga livet och stärkte den ekologiska validiteten hos de kliniska
bedömningsmetoderna för TD.
7
LIST OF SCIENTIFIC PAPERS
I.
Malmenholt, A., Lohmander, A. & McAllister, A.
Childhood apraxia of speech: A survey of praxis and typical speech
characteristics. Logopedics Phoniatrics Vocology 2017, 42(2): 84-92.
II.
Malmenholt, A., McAllister, A. & Lohmander, A.
Orofacial function, articulation proficiency, and intelligibility in 5-year-old
children born with cleft lip and palate. The Cleft Palate-Craniofacial Journal
2019, 56(3): 321-330.
III.
Malmenholt, A., McAllister A., Lohmander, A. & Östberg, P.
Speech feature profiles in 5-year-olds with speech sound disorder related to
suspected childhood apraxia of speech or cleft palate. Manuscript submitted,
2020.
IV.
Malmenholt, A., Östberg, P., McAllister, A. & Strömbergsson, S.
Language profiles in 5-year-olds with speech sound disorder related to
suspected childhood apraxia of speech or cleft palate. Manuscript under
review.
8
LIST OF ABBREVIATIONS
22q11.2DS
AOS
ASHA
22q11.2 deletions syndrome, earlier called CATCH22,
DiGeorge syndrome, velo-cardio-facial syndrome
Acquired apraxia of speech
American Speech-Language-Hearing Association
BCLP
Bilateral cleft lip and palate
CAS
CELF-4
CP±L
Childhood apraxia of speech
Clinical Evaluation of Language Fundamentals
Cleft palate with/without cleft lip
CPH
CPO
CPS
DLD
ICS
ISPc
ISPv
MRI
non-CAS SSD
NOT-S
PCC
sCAS
SLP
SMCP
SSD
SVANTE
UCLP
Cleft of the hard and soft palate
Isolated cleft palate (including CPH+CPS)
Cleft of the soft palate only
Developmental language disorder
Intelligibility in context scale
Inconsistency severity percentage of consonants
Inconsistency severity percentage of vowels
Magnetic resonance imaging
SSD but not CAS
Nordic Orofacial Test - Screening
Percentage of consonants correct
Suspected childhood apraxia of speech
Speech language pathologist
Submucous cleft palate
Speech sound disorder
Swedish articulation and nasality test
Unilateral cleft lip and palate
9
1 INTRODUCTION
Speech is the common way for humans to express thoughts, opinions and emotions. In unity
with language skills the spoken output makes it possible to communicate in a reciprocal way
with others. In typical development speech and language skills mature and develop without
effort. Children with delayed or deviant speech and/or language development face limitations
when communicating.
1.1 GENERAL MOTIVATION
This thesis project was based on my professional curiosity and frustration as a clinical speech
language pathologist (SLP) concerning the lack of treatment progress in children with
childhood apraxia of speech (CAS) and in children with speech disorders related to cleft palate
with/without cleft lip (CP±L). Anecdotal reports and my clinical experience of these children
indicated some overlap of speech difficulties between the two groups. In addition, meeting
children with their parents in the clinic made it clear that communication in everyday life is not
only influenced by the severity of the speech disorder, but also by comorbid language or
neurodevelopmental disorders and the child’s and significant other’s environment.
Delays in speech and language acquisition are the most common problems in preschool
children. Their prevalence in 5-year-olds has been estimated to ~12% for speech and language
delay, ~7% for language delay only and ~8% for speech delay only (Law, Boyle, Harris,
Harkness, & Nye, 2000). More recently the prevalence of language disorder in 4-5-year-olds
has been reported to be ~10% (Norbury et al., 2016). At ages 4-5 years, 12% of parents judged
that their child’s “speech (is) not clear to others” and 6% that “speech (is) not clear to the
family” (McLeod & Harrison, 2009). This thesis project is mainly concerned with the latter
group of children, whose ability to communicate with others is markedly restricted at age 5.
Including only a restricted age group in this project had several reasons. At 5 years of age, most
children cooperate reliably during standardized assessments and normative data on speech and
language competence are available. Swedish-speaking 5-year-olds typically master the
Swedish phoneme inventory, with phonemes /s/ and /r/ being the last to be established
(Blumenthal & Lundeborg Hammarström, 2014). It has been suggested that 5-year-old children
with speech disorder are not yet aware of their speech problem but aware of the inability of
their communication partners to “hear” and understand what they say (McCormack, McLeod,
10
McAllister & Harrison, 2010). Language competence at 5 years of age typically includes the
ability to tell or re-tell a coherent story, to understand what is read or listened to, and to follow
or remember spoken instructions (Bishop et al., 2016). In addition, school entry is approaching
and maximizing communication skills, including speech ability, is an important goal for the
child, family and the professionals involved (Kuehn & Moller, 2000). Language problems at 5
years of age are likely to persist (Stothard, Snowling, Bishop, Chipchase & Kaplan, 1998;
Institute of Medicine, 2016) and there is little evidence that the gap between children with and
without language disorder closes over time (Lundeborg, McAllister, Samuelsson, Ericsson, &
Hultcrantz, 2009; Rice & Hoffman, 2015; Institute of Medicine, 2016). Despite the close
relationship between speech motor and language production (Vuolo & Goffman, 2018),
children with atypical development may present with isolated speech, language, or mixed
difficulties.
1.2 CHILDHOOD APRAXIA OF SPEECH
Already 129 years ago, three clinical cases of children with ‘defects in articulation’, fitting the
description of the speech sound disorder we today call CAS, were published in the Journal of
Mental Science (Hadden, 1891). In ‘The development and disorders of speech in childhood’
by Muriel Morley (1957), the clinical history and signs of twelve cases with ‘developmental
articulatory apraxia’ were described and followed longitudinally. These clinical cases are
strikingly alike present patients diagnosed with CAS. Morley addressed important points to
assist in diagnostics, still relevant in today’s clinical settings, such as information about family
history, motor, speech, social and personal development of the child. Phonetic analysis of
speech sounds from several speech tasks (realizations of phonemes in different word positions,
repetition of phrases and spontaneous speech) were proposed as well as screening of language
competence. Difficulties with differential diagnosis of less severe cases of CAS, dysarthria and
dyslalia, or a combination of these, were highlighted. However, Morley did not present a list
of diagnostic speech features but rather acknowledged the heterogeneity of the diagnosis. In
large, Morley’s understanding of the disorder and awareness of similarities with the acquired
form of apraxia of speech after brain damage in both children and adults was sharp-eyed.
11
1.2.1 Terminology
The term ‘childhood apraxia of speech’ was endorsed by the American Speech-Language–
Hearing Association (ASHA, 2007). Previous terms for the disorder include: ‘developmental
articulatory apraxia’ (Morley, Court & Miller, 1954), ‘developmental apraxia of speech’
(Rosenbek & Wertz, 1972), ‘developmental verbal dyspraxia’ (Crary, Landess, & Towne,
1984) to speech delay–apraxia of speech (SD-AOS) (Shriberg et al., 2003) to name a few (for
the early history of terminology, see Hall, Jordan & Robin, 1993). The term apraxia had
traditionally been used to describe the inability to produce purposeful movements in the
absence of paralysis, sensory impairment, comprehension problems or intellectual disorders
(Liepmann, 1900). Using the term apraxia for a developmental speech problem caused
confusion, indicating the loss of a skill not yet acquired. Both research approaches and
terminology in apraxia in childhood have been based on knowledge about the adult form of the
disorder, acquired apraxia of speech (AOS). The description of AOS as a distinct speech
impairment occurring independently or in combination with language disturbance (aphasia)
and/or neuromuscular involvement (dysarthria) (e.g. Darley, 1982), resembles our
understanding of the childhood form, as does the definition: AOS is a “neurologic speech
disorder that reflects an impaired capacity to plan or program sensorimotor commands
necessary for directing movements that result in phonetically and prosodically normal speech”
(Duffy, 2020, p. 4). However, AOS results from a known, acquired brain damage typically
following stroke (Duffy, 2020), degenerative processes (progressive AOS) (e.g. Josephs et al.,
2012), tumor or traumatic injury (Duffy, 2020). Isolated AOS is rare, complicating the
identification of the specific location of the damage to the brain. In addition, different lesion
locations have been reported to result in similar clinical presentations. More recent studies
suggest that AOS is associated with lesions in brain areas involved in speech motor control (for
an overview of brain damage associated with AOS, see Moser, Basilakos, Fillmore &
Fridriksson, 2016). Neurological evidence for brain dysfunction in children, in analogy to the
adult form, was studied on during the 1970s, using electroencephalography (EEG) (e.g.
Rosenbek & Wertz, 1972; Yoss & Darley, 1974; Williams, Ingham & Rosenthal, 1981).
Findings were inconclusive and reports mainly indicated none, mild or nonspecific
abnormalities. Routine clinical MRI scans are not sensitive enough to identify neural anomalies
in children with idiopathic CAS (Morgan & Webster, 2018). However, advances in genetic
research and the use of voxel-based morphometry have shown morphological abnormalities in
the supramarginal gyrus and planum temporale for children with a subtype of speech sound
disorder characterized by persistent speech sound errors (Preston et al., 2014). The discovery
12
that a mutation of FOXP2 was associated with CAS, started a new era of etiologic research
(Lai, Fisher, Hurst, Vargha-Khadem, & Monaco, 2001). FOXP2 is widely expressed in the
fetal and adult brain, where it regulates the expression of other genes (Spiteri et al., 2007). It is
now evident that CAS is associated to several genetic conditions and different gene pathways.
The debate on criteria and diagnosis of CAS started with a critical review by Guyette and
Diedrich (1981), who challenged the evidence for CAS as a specific diagnostic entity. The
authors surveyed more than 100 publications and found contradictions, confusions and
questionable designs in both clinical and experimental studies. Difficulties with study selection
or inclusion and varying ages, intellectual levels, language abilities and severity of problems
hampered cross-study comparisons and the knowledge base of CAS. Apparently, many
clinicians based their diagnoses on the duration of difficulties and results of speech-language
training (e.g. Rosenbek, 1978; Yoss & Darley, 1974). In a literature review of management
strategies for ‘developmental apraxia of speech’ Pannbacker (1988) stated that therapy
techniques used for children were based on clinical experience and the literature about therapy
for acquired apraxia.
1.2.2 Classification
In this context, the seminal work of Lawrence D. Shriberg and colleagues must be
acknowledged. They developed the speech disorders classification system (SDCS) which has
been updated over several decades, and finalized in 2017 (e.g. Shriberg, 1993; Shriberg, 2010a;
Shriberg, 2010b; Shriberg et al., 2010; Shriberg et al., 2017a). It is a major contribution to the
development of the field of speech sound disorders in general and to CAS in particular. The
SDCS is a framework consisting of four levels. The levels are linking ‘etiological processes’
(level I) (distal causes including explanatory pathways of a specific speech disorder) to ‘speech
processes’ (level II) (proximal causes including fundamental processes underlying speech
production, e.g. representation, transcoding and execution of speech, mediated by feedforward
and feedback processes) to ‘clinical typology’ (level III) (behavioral phenotype) which are the
actual speech behaviors that can be classified using ‘diagnostic markers’ (level IV) (criterial
signs of the phenotypes). The goal is to identify a single, conclusive, behavioral, diagnostic
marker (level III and IV) for each of the eight speech disorders in the typology. This means
finding a marker that maximizes sensitivity and specificity for every speech disorder leading
to correct prediction of true positives and true negatives. Another goal has been to use this
13
diagnostic marker (level IV) to identify and validate biomarkers (level I) of that same disorder,
connecting the marker to proximal causes fitting into the underlying speech production
processes (level II). By linking all four levels, circular reasoning can be avoided. CAS
characteristics will thus not be found in participants included in studies just because they are
suspected of having CAS. Such circularity cannot be overcome without a line of arguments
convincingly connecting all levels. The ‘Pause Marker’ (PM) was presented as a behavioral
diagnostic marker for CAS (level IV) both for research and clinical use (Shriberg et al., 2017a,
2017b, 2017c, 2017d). The PM is an acoustically aided perceptual sign quantifying the speech
precision of phrasing, that is, inappropriate pauses of different types (Shriberg et al., 2017c).
It is built on data reduction and analyses computed in the PEPPER (Programs to Examine
Phonetic and Phonological Evaluation Records, Shriberg et al., 2010) platform, freely available
(http://www.waisman.wisc.edu) for analysis of American English speech material. The PM is
quantified using 24 utterances, or at least 40 between-words opportunities, from a continuous
speech sample. However, this requirement excludes participants who do not produce longer
utterances and/or those with extremely low intelligibility, making the PM inapplicable to
speakers with very low verbal output, such as young children and those with severe CAS.
The American Speech-Language–Hearing Association’s Technical Report on CAS was
presented in 2007 and is still referred to as the guideline for CAS. The content was produced
by the Ad Hoc Committee on Apraxia of Speech in Children. The Committee had reviewed
and summarized the research background, addressed terminology and provided a definition of
the disorder. The three diagnostic criteria of the disorder were described as: (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 (ASHA, 2007).
Despite much promising work on CAS for more than 60 years, a number of questions about
the etiology, pathology and validity of reported symptoms still remain. The current
understanding of the underlying difficulty in CAS is that of an impairment of transcoding
linguistic content into speech movements. The core disability is in sensorimotor planning,
which identifies the acoustic goals and the spatial configurations of the vocal tract to achieve
them and in programming, which provides the muscle-specific requirements so that structures
move with the correct range of motion, strength, speed and direction (Strand, 2020). CAS is
defined as a neurological childhood speech sound disorder in which the precision and
consistency of movements underlying speech are impaired in the absence of neuromuscular
deficits. CAS is said to occur as a result of known neurological impairment, in association with
14
complex neurobehavioral disorders of known or unknown origin, or as an idiopathic
neurogenic speech sound disorder (ASHA, 2007). The clinical prevalence of CAS in English-
speaking children has recently been estimated to 2.4% for the idiopathic form and 4.3% when
associated with complex neurodevelopmental disorder (Shriberg, Strand, Jakielski, & Mabie,
2019). An additional clinical prevalence has been reported for concurrent CAS and dysarthria
(4.9%) in children with complex neurodevelopmental disorder (Shriberg et al., 2019).
Following the raised awareness of CAS, high rates of possibly false positive cases have been
reported (Shriberg & McSweeny, 2002; Shriberg, Potter, & Strand, 2011). On the other hand,
CAS may also be underdiagnosed in populations with genetic or complex neurodevelopmental
disorders (Cleland, Wood, Hardcastle, Wishart & Timmins, 2010).
1.2.3 Speech characteristics
Several checklists of diagnostic speech features for CAS have been surveyed (e.g. Forrest,
2003; Joffe & Pring, 2008; Meredith & Potter, 2011) and published for research purposes
(Shriberg et al., 2011), but so far no quantifiable measures have been presented and
operationalized that accurately discriminates all cases of CAS from other communication
disorders. In addition, overlapping speech symptoms within individuals and between groups of
individuals with SSD are commonly reported (e.g. Ballard, Granier, & Robin, 2000; McNeil,
Robin & Schmidt, 2009). Furthermore, no single neurological or behavioral diagnostic marker
has been found yielding for all cases of CAS (e.g. ASHA, 2007; Shriberg, Lohmeier, Strand &
Jakielski, 2012). Two studies have attempted to identify quantifiable speech characteristics for
a diagnosis of CAS (Murray, McCabe, Heard, & Ballard, 2015; Shriberg et al., 2017a). Both
investigated prosodic features of speech such as lexical stress and syllable segregation (Murray
et al., 2015) or between-words pauses (PM) (Shriberg et al., 2017a). Four measures in
combination were found to significantly predict a CAS diagnosis in a regression model (R2 =
.91): syllable segregation, percentage of stress matches, percentage phonemes correct on
polysyllables and the accuracy on a diadochokinesis (DDK) task (Murray et al., 2015).
However, in this model children with CAS plus DLD and participants with submucous cleft
palate were omitted, making the findings less generalizable to unselected groups of children
with SSD. Arguing that clinical SLPs need to diagnose and treat children with CAS despite the
current lack of evidence-based procedures, Iuzzini-Seigel and Murray (2017) proposed a 12-
feature checklist for clinical use, based on a previous checklist published for research (Shriberg
et al., 2011). Most importantly, the Iuzzini-Seigel and Murray checklist (2017) included
operationalized definitions of all features listed. As a cut-off for a positive diagnosis of CAS
15
five optional features as a minimum in addition to the mandatory feature speech sound
inconsistency were required, that is, six features from the list observed at least once. The 12
CAS features commonly associated with CAS with operational definitions (Iuzzini-Seigel &
Murray, 2017) are summarized in table 1 (based on table 1 in Malmenholt et al., submitted
2020) and structured with respect to the three primary ASHA criteria (ASHA, 2007).
Table 1. Operational definitions for the 12-feature checklist of CAS proposed by Iuzzini-Seigel and
Murray (2017) structured with respect to primary criteria for CAS (ASHA, 2007)
ASHA's three
primary criteria
(2007)
Vowel error
both vowel substitutions and distortions are considered incorrect
Consonant distortion
the speech sound is recognizable as a specifi c consonant but not
produced accurately
Speech sound
inconsistency
variable production of phonemes (i .e., phonemic inconsistency) words
or phrases (i.e., token-to-token inconsistency across multiple
opportunities)
Nasal resonance hypo- or hypernasal resonance
Intrusive schwa
addition of a schwa betwee n consonants
Voicing error
a sound produced between voicing categories or as its voicing cognate
Groping
prevocalic, sil ent articulatory searching prior onset of phonation and
speech production
Difficulty achieving
initial articulatory
configurations or
transitionary movement
gestures
lengthened or disrupted, hence uncoordinated, movements or
coarticulatory gestures at word start or between sounds within words
Increased difficulty with
multisyllabic words
the number of errors increases disproportionately if number of
syllables increase
Stress errors
appropriate stress is not correctly produced at the word or sentence
level
Syllable segregation
inappropriate pauses between sounds, syllables or words leading to
segregation and lack of smooth transitions within words
Slow rate atypically slow speech rate
c) inappropriate
prosody,
especially in
the realisation of
lexical or phrasal
stress
Speech features
commonly associated
with CAS
Operational definition according to Iuzzini-Seigel & Murray (2017)
a) inconsistent
errors on
consonants and
vowels in
repeated
productions of
syllables or
words
b) lengthened
and disrupted
coarticulatory
transitions
between sounds
and syllables
16
1.2.4 Childhood apraxia of speech comorbidity
The literature on language abilities in children with CAS is rather sparse. Possibly, the search
for reliable diagnostic markers and defining the speech disorder per se has had priority. The
reported cooccurrence of CAS with language disorder varies from 46 to 82% (Thoonen,
Maassen, Gabreels, Schreuder, & de Swart, 1997; Lewis, Freebairn, Hansen, Iyengar, &
Taylor, 2004; Iuzzini, 2012; Vuolo & Goffman, 2018; Zuk, Iuzzini-Seigel, Cabbage, Green, &
Hogan, 2018; Murray, Thomas, & McKechnie, 2019). Research in the 1970s described a gap
between receptive and expressive language ability in patients with CAS, with better receptive
than expressive abilities (e.g. Rosenbek & Wertz, 1972). This gap has also been reported in a
more recent study (Murray et al., 2019). In that study, morphological disorder was found in
48% of 4-5-year old children with CAS. The question raised was whether the cooccurrence of
difficulties with motor speech and morphology was to be seen as speech motor difficulties
affecting language or cooccurrence of both speech and language disorder (Murray et al., 2019).
Also, interactions between language and gross and fine motor skills in children with language
disorder have been reported (e.g. DiDonato Brumbach & Goffman, 2014; Hill, 2001; Zelaznik
& Goffman, 2010). After reviewing the literature on cooccurrence of motor and language
impairment in children, Hill (2001) concluded that shared cognitive processes could be a
plausible explanation. Two processing streams, the ventral and dorsal stream, have been
proposed for higher-order cognitive processes, including language production and
comprehension (for a detailed review, see Cloutman, 2013). The dual stream model of speech
processing (e.g. Hickock & Poeppel, 2004, 2007, Poeppel, Emmorey, Hickock & Pylkkänen,
2012) attributes the role of supporting speech comprehension to the ventral stream (e.g.
semantic and phonological processing, long-term storage of semantic information, sound
recognition); it represents a sound-to-meaning interface. The dorsal stream is attributed the role
of sensory-motor integration (e.g. auditory-motor transcoding, syntactic analysis, phonological
memory); an auditory-to-motor translation. Although functionally specialized and
anatomically separate, the streams need to interact closely for successful production and
comprehension of language (Hickock, 2012) and synergies between these white matter tracts
for language functioning are proposed (Rolheiser et al., 2011). It is evident that the language
network is much more extended than previously suggested and that the lateralization to the left
hemisphere is not as exclusive as proposed in earlier research (Hagoort, 2017). Taking
advantage of the technical development of functional MRI and voxel-based morphometry,
brain anomalies can be studied in greater detail than before. Nevertheless, in children with
DLD, structural brain changes have not been found in the classical language tracts, that is, the
17
ventral or dorsal stream. However, findings across studies have been inconsistent, possibly
explained by the heterogeneity of DLD (e.g. Liégeois et al., 2014; Morgan et al., 2018).
The discovery of the KE family in the 1990s changed the understanding of CAS. Because of a
mutated FOXP2 gene, affected members had CAS, orofacial dyspraxia and language disorder
including difficulties producing morphosyntax and the comprehension of complex
grammatical structures; some also had dysarthria (Watkins, Dronkers, Vargha-Khadem, 2002;
Morgan & Liégeois, 2010). Developments in neurogenetics followed, and structural and
functional brain images in affected and unaffected family members were compared. Reduced
gray matter volumes were found in for example Broca’s area, and abnormally large volumes
of gray matter in Wernicke’s area. In analogy to the anatomical finding, there were functional
differences in affected members, such as, low activations in speech-related cortical regions but
overactivations of regions not typically speech-related (Vargha-Khadem et al., 1998; Vargha-
Khadem, Gadian, Copp, & Mishkin, 2005). However, FOXP2 mutations were found to be rare
in children with non-syndromic CAS (Laffin et al., 2012). Since the discovery of the KE family,
several copy number variations in diverse locations on different chromosomes have been
reported in sporadic cases of CAS (Laffin et al., 2012). Another multigenerational family with
autosomal dominant inheritance of CAS, but with no causal gene identified, has been described
(Peter, Button, Stoel-Gammon, Chapman, & Raskind, 2013) as has a family with CAS not
explained by a FOXP2 variant (Liégeois et al., 2019). This latter family is especially intriguing,
because family members are primarily affected by CAS without cooccurring language or
literacy impairment. Neuroanatomical findings indicate an atypical developmental of the dorsal
language network responsible for auditory-motor translation as an explanation for CAS in this
family.
To summarize, advances in neuroimaging methods have uncovered both functional and sub-
macroscopic brain anomalies in individuals with CAS. These have mainly been presented as
gray and/or white matter reductions or elevations in brain regions typically activated during
speech or language processes (Liégeois, Mayes, & Morgan, 2014) or atypically activated,
probably indicating compensatory strategies (Vargha-Khadem et al., 2005). A new functional
connectivity approach has been recently presented to explain CAS (Liégeois et al., 2019). For
individuals with DLD, examined in adolescence and young adulthood, altered brain structures
in both the dorsal and ventral pathways have been reported (Lee, Dick & Tomblin, 2020).
Further studies investigating the underlying neurobiological networks for typical and atypical
development of speech and language abilities are to be expected in the future.
18
1.3 CLEFT PALATE ± LIP
Worldwide about a quarter of a million babies with cleft lip and/or palate (CLP) are born every
year (Mars, Sell, & Habel, 2008). The corresponding figure for Sweden is 150-200 (Hagberg,
Larson, & Milerad, 1998). Clefts are the result of an interruption in embryologic growth and
arise during the 4th and 10th week of the developing embryo (Peterson-Falzone, Hardin-Jones
& Karnell, 2010). Children born with CP±L form a heterogeneous group: the extent and
etiology of the cleft differ with a high frequency of associated anomalies or syndromes. Clefts
are described based on the structures involved which are the lip, alveolus, hard palate and soft
palate. Cleft types affecting the palate (CP±L) are usually divided into bilateral cleft lip and
palate (BCLP), unilateral cleft lip and palate (UCLP), cleft affecting the hard and soft palate
(CPH), cleft of the soft palate only/isolated cleft (CPO) and submucous cleft (SMCP).
Figure 1. (a) bilateral cleft lip and palate, (b) unilateral cleft lip and palate, (c) cleft affecting the hard
and soft palate, (d) cleft of the soft palate only/isolated cleft and (e) submucous cleft.
Illustrations by Liisi Raud Westberg
19
A cleft palate affects eating, speech development, ear function/hearing, dentition and facial
appearance. For optimal development of these structures, the cleft is surgical closed. While it
is the cleft in the palate that may cause difficulties with eating, speech, and ear function/hearing,
and should therefore be closed early, early surgery in the hard palate may cause problems with
maxillofacial growth. One- or two-stage protocols for cleft palate repair are nowadays usually
performed between 6 and 24 months of age. However, different techniques, staging and timing
are in practice and there is still no standard protocol to attain optimal results for all affected
areas (Leow & Lo, 2008; Reddy, Gosla Reddy, Vaidhyanathan, Berge, & Kuijpers-Jagtman,
2017).
Prerequisites for speech production in children with CP±L are altered owing to both structural
and functional limitations. Following surgical interventions, structure and function are
repeatedly altered during the first years of speech development in children with CP±L.
Although lip and tongue strength and endurance have been found to be normal in children with
UCLP (Van Lierde et al., 2014) and tongue structure and function per se is considered
unaffected in children born with CP±L (Peterson-Falzone et al., 2010), adaptive behaviors are
reported. These behaviors are linked to velopharyngeal inadequacy resulting in articulatory or
compensatory strategies. Compared to non-cleft peers, speakers with a repaired cleft lip
evidence considerable functional differences in motor activity (Atkinson & Howard, 2011) and
atypical patterns of tongue to palate contact have been observed, including retracted
articulation and overuse of the tongue dorsum (e.g. Morley, 1970; Gibbon, 2004; Howard,
2004). In addition, atypical complete tongue-palate constriction during production of high
vowels have been reported (e.g. Gibbon, Smeaton-Ewins, & Crampin, 2005) and increased
variability of lip movements during speech production (Rutjens, Spauwen, & van Lieshout,
2001). Difficulties with tongue grooving, needed for production of vowels (Stone, Shawker,
Talbot & Rich, 1988), have been reported in some children with CP±L. Tongue grooving is
also required for production of sibilant sounds, known to be frequently affected in children with
CP±L (e.g. Harding & Grunwell, 1996; Morley, 1970).
1.3.1 Speech characteristics
Speech difficulties in children born with CP±L were traditionally categorized as ‘articulation
disorders’, primarily related to the anatomical relationships and alterations within the oral
cavity and vocal tract before and after surgical repair. In the 1990s, however, cleft speech
20
characteristics were reconsidered in the context of phonological development (e.g. Harding &
Grunwell, 1996). Speech characteristics in cleft palate speech can be divided into two types:
active and passive (Harding & Grunwell, 1996, 1998; Hutters & Brønsted, 1987).
Passive speech characteristics occur as a direct consequence of limited structures or muscle
functions, that is, children speak in a way that would have sounded typical, if there had not
been a structural abnormality or dysfunction. Commonly reported passive speech
characteristics include hypernasality, audible nasal airflow errors, and weak and/or nasalized
consonants. Consequently, passive speech characteristics require surgery and are not treatable
with speech therapy. In contrast, active speech characteristics appear to be a child’s
spontaneous attempt to compensate for the structural abnormality and are used to create
phonological contrast. Intended consonants are produced using compensatory articulatory
gestures, resulting in for example backing or glottal stops and may also include speech sounds
not found in the language in question.
Active cleft speech characteristics can be the result of early mislearning and are associated with
velopharyngeal insufficiency and/or a fistula and may persist despite successful surgical
intervention (Harding & Grunwell, 1998; Hutters & Brønsted, 1987). Active cleft speech
characteristics can be considered in a phonological context and treated with speech therapy.
Every child’s acquisition of the speech sound system includes learning of the language-specific
phonological structure and organization (Gierut & Morrisette, 2005). Articulatory placement
and movements to produce correct sounds, that is, articulation and motor learning, are required
(Fey, 1992). In children born with CP±L, not all develop normal speech despite surgical
intervention. Actually, speech in 5-year-olds with CP±L varies from typical articulation
proficiency and intelligibility to severe difficulties (Chapman, 2017; Klintö, Salameh, &
Lohmander, 2016). It has been reported that about 20% to 50% of children with UCLP display
speech difficulties at 5 years (e.g. Lohmander & Persson, 2008; Nyberg, Peterson, &
Lohmander, 2014; Sell et al., 2015) and at least 50% when including children with several cleft
types and syndromes (Britton et al., 2014).
Differences in speech outcome related to different surgical protocols have been sparsely
investigated (Lohmander, 2011). However, in the Scandcleft trials the outcome after four
different surgical protocols for primary repair of the cleft palate in 450 children born with
UCLP was compared (Semb et al., 2017). Whereas the results confirmed the high prevalence
of speech disorders, none of the protocols were found favorable except for one speech error
type, namely the retracted oral consonant error or backing. This error type was most commonly
found in children who had the cleft in the hard palate repaired later, even if the soft palate cleft
21
was closed early (Willadsen et al., 2017). No differences in perceived velopharyngeal function
or hypernasality were significantly related to the different protocols (Lohmander et al., 2017).
1.3.2 Cleft palate ± lip and comorbidity
Reports on the prevalence of additional malformations in the cleft population vary depending
on cleft type and definition of associated anomalies and syndromes. Several studies report an
overall prevalence of about 30% (Chetpakdeechit, Mohlin, Persson, & Hagberg, 2010;
Impellizzeri, Giannantoni,Polimeni, Barbato, & Galluccio, 2019; Milerad, Larson, Hagberg, &
Ideberg, 1997). A consistent finding is that patients with CPO (including submucous clefts),
although having the rarest form of oral clefting, have the highest likelihood of associated
anomalies. Also, children with BCLP have a higher prevalence of associated anomalies than
children with UCLP (e.g. Peterson-Falzone et al., 2010).
Language abilities in children with CP±L has not received much attention (Hardin-Jones &
Chapman, 2011). This could be owing to the overt nature of cleft speech characteristics,
potentially masking language difficulties. Language competence in 5-year-olds with
nonsyndromic cleft lip and/or palate has been suggested to be delayed rather than disordered.
A catch-up due to maturation is reported, resulting in non-significant differences compared to
language competence in non-cleft peers (Boyce, Kilpatrick, Reilly, Da Costa, & Morgan, 2018;
Collett, Leroux, & Speltz, 2010). In a recent meta-analysis, the conclusions were similar, after
examining the literature (n=31) on speech and language development in children with non-
syndromic cleft lip ± palate from 1950 to 2018, including ages 0 through 8:11 (Lancaster et al.,
2020). Both expressive and receptive language competence were examined, resulting in an
average effect size of -0.57 SD unit lower for expressive language competence and -0.59 SD
unit lower for receptive language skills for children with non-syndromic CP±L compared to
competence of peers without clefts. The overall conclusion about language development and
competence in children with non-syndromic CP±L was that of early onset language delay but
with a decreasing negative impact over time (Lancaster et al., 2020). However, two studies not
included in the analysis targeting language competence in preschool and early school-aged
children with non-syndromic CP±L reported DLD in 14% to 20% (Klintö et al., 2019; Morgan
et al., 2017), indicating that there are both children with and without cooccurring DLD in the
heterogeneous group of children born with non-syndromic CP±L.
22
A significantly increased risk for comorbidities (e.g. psychiatric disorder, intellectual disability,
language disorder, autism spectrum disorder, psychotic disorder, attention deficit/hyperactivity
disorder) was found in a large Swedish register cohort study on children with orofacial clefts
(Tillman et al., 2018). In total ~19% with CLP and ~23% with CPO received at least one
psychiatric diagnosis, compared to 11% of children without cleft. The highest hazard ratio of
the different comorbidities was found for language disorder (aHR = 4.89) and intellectual
disability (aHR = 4.19). A sibling analyses suggested that the heightened risk for comorbidities
could not be explained by familial influence.
Dyspraxia, or speech features typically associated with CAS, have been reported with a high
frequency in syndromic cleft populations with 22q11.2 deletion syndrome (22q11.2DS)
(D’Antonio, Scherer, Miller, Kalbfleisch, & Bartley, 2001; Kummer, Lee, Stutz, Maroney, &
Brandt, 2007) suggesting a phenotypic overlap between CAS and CP±L. Thus, the highest
clinical prevalence of CAS (11.8%) among complex neurodevelopmental disorders was
recently reported for 22q11.2DS (Shriberg et al., 2019). Not all children with 22q11.2DS are
born with a cleft, but 49% to 82% were reported to have a palatal abnormality (e.g. D’Antonio
et al., 2001; Márquez-Ávila et al., 2015; Persson, Lohmander, Jönsson, Óskarsdóttir, &
Söderpalm, 2003; Solot et al., 2019), so that a substantial proportion of children with
22q11.2DS present with a cleft and CAS. Furthermore, there have been reports of submucous
clefts being found when patients are assessed for suspected CAS (Murray et al., 2015) and
CAS was identified in a patient with unilateral cleft lip and palate and hard to treat SSD
including glottal stops (Lohmander & Persson, 2008). These cases with a potentially dual
diagnosis raise interest in the overlapping speech characteristics and cooccurrence of CAS in
children born with CP±L.
23
2 AIMS
2.1 GENERAL AIM
The overall aim of the project was to explore and investigate speech and language difficulties
in children with childhood apraxia of speech and in children with repaired cleft palate at age 5
years to broaden the knowledge base on CAS and search for factors explaining unfavorable
speech outcome in children with cleft palate. Both children with suspected CAS, diagnosed
CAS, and CP±L were of interest for assessment and comparison of speech and language
abilities.
2.2 SPECIFIC AIMS
The specific aims were to:
• survey the knowledge among Swedish SLPs’ about speech characteristics and other
deficits commonly associated with suspected CAS (Study I)
• examine if orofacial function in children born with CP±L differs from that in children
without clefts and could be an explanatory factor for speech outcome (Study II)
• evaluate a checklist for diagnosis of CAS, constructed for English-speaking children
(Study III)
• describe the prevalence of CAS speech features in children with severe speech sound
disorders of different origins, looking for similarities and differences in speech feature
profiles (Study III)
• describe the prevalence and profile of cooccurring language disorder in children with
severe SSDs of different origins (Study IV)
• investigate the correspondence between SLP assessments of speech and language in
children with severe SSDs and parental ratings of intelligibility and functional
communication in their children’s everyday lives (Studies II and IV)
24
3 METHOD
3.1 PARTICIPANTS
For the survey study (study I), 289 Swedish SLPs working with pre- and primary school-aged
children (ages 3 to 9) throughout Sweden were contacted per email and invited to anonymously
answer the web-based questionnaire. In total 178 questionnaires were returned, which equals a
survey response rate of 62%. Questions targeting the background of the SLPs revealed
graduation from different universities between the years 1972 and 2011. The largest proportion
of answers came from SLPs’ with less than five years (41%) or more than ten years (37%) of
clinical experience. Most respondents worked in hospitals or public speech and language
clinics (44%). Other workplaces were child habilitation services (24%), university hospitals
(12%), special pre- and primary schools for children with speech and language disorders (8%),
and private clinics (8%).
In total 67 five-year-old children (4:10-5:11) were included in studies II-IV, as illustrated in
figure 1. All children had at least one native Swedish-speaking parent. They came from two
different patient groups: children born with cleft palate (CP±L) and children with suspected
CAS (sCAS). Fifty-two children, born with a cleft affecting the palate also including additional
malformations, came from the original cohort of 88 children born between July 2009 and June
2011. These children were treated by the Stockholm Craniofacial Team and were included in
study II. Children with no speech production and internationally adopted children were
excluded. Study III included a subgroup of participants with CP±L from study II, children with
disordered speech, who scored at least two standard deviation units below the mean on a
standardized articulation test (n=19). Study IV included children with CP±L from study III
who volunteered for additional language testing (n=8). For study III and IV children with
suspected or diagnosed CAS (n=16) born between April 2010 and March 2012 were referred
for a second opinion by community-based SLPs. One child was excluded owing to difficulties
with participation.
25
Figure 2. Flowchart over participants in study II, III and IV. BCLP, bilateral cleft lip and palate; UCLP,
unilateral cleft lip and palate; CPH, cleft of the hard and soft palate; CPS, cleft of the soft palate only; SMCP,
submucous cleft; CP±L, cleft palate with or without cleft lip; CAS, childhood apraxia of speech.
Exclusion criteria applied: Internationally adopted (n=23);
no speech (n=10); late registration (n=3)
Inclusion of participants from study II with a speech score
two standard deviation units below the mean (n=19)
Inclusion of participants from study III volunteering for
additional language testing (n=23)
26
3.2 MATERIAL
3.2.1 Speech samples
All speech samples came from the Swedish Articulation and Nasality Test (SVANTE)
(Lohmander et al., 2005).
Single word naming: For single word naming the 74 pictures from the test were used. The test
primarily targets the production of consonants vulnerable to a cleft condition but is also
recommended for the analysis of speech disorders related to, for example, motor speech
disorders (Lohmander, Lundeborg, & Persson, 2017).
Sentence repetition: Thirteen short sentences, with different types of consonants (high-
pressure, low-pressure, nasal or mixed), were produced through imitation by the children.
Connected speech: To elicit connected speech the children freely described the events from a
picture of a day on the beach.
3.2.2 Observations of orofacial function
All information about orofacial function came from the Nordic Orofacial Test - Screening
(NOT-S) (Bakke, Bergendal, McAllister, Sjögreen, & Åsten, 2007).
Orofacial function: Twelve domains are included; six domains through SLP examination and
six through interviewing parents about orofacial function of the child. The domains included
sensory function, breathing, habits (e.g. sucking fingers, grinding teeth during daytime),
masticatory muscles and jaw function, chewing and swallowing, drooling, dryness of the
mouth, the face at rest, facial expression, oral motor function, and speech.
3.2.3 Language samples
All language samples came from the Clinical Evaluation of Language Fundamentals
(CELF-4) (Semel, Wiig, & Secord, 2003; Swedish version 2013).
Receptive Language: All subtests targeting receptive language skills were administered:
‘Concepts and Following Directions’, ‘Word Classes’ and ‘Sentence Structure’.
Expressive Language: All subtests targeting expressive language skills were administered:
‘Word Structure’, ‘Recalling Sentences’ and ‘Formulated Sentences’.
27
3.2.4 Questionnaires
3.2.4.1 SLP questionnaires
The author was responsible for the construction of the survey questionnaire, data collection
and phonetic transcription.
Data collection for study I was based on a survey questionnaire. The questionnaire was
constructed and pilot tested with four clinically and academically experienced SLPs. The 22
questions targeted the background of the SLPs, their clinical and theoretical knowledge and
experience of CAS, estimation of own competence and prevalence of children with CAS in the
SLPs’ clinical settings.
3.2.4.2 Parental questionnaires
The Intelligibility in Context Scale (ICS) (McLeod et al., 2012a; Swedish translation, 2012b)
and Children’s Communication Checklist (CCC-2) (Bishop, 2003: Swedish translation 2011)
were used.
Parental ratings: Parents filled in two questionnaires, one rating the degree to which their
child’s speech was understood by different communication partners and one rating functional
communication in everyday life.
3.2.5 Audio and video recordings
For participants with sCAS, speech and language samples were documented with audio and
simultaneous video recordings (Digital Video Camrecorder, Canon FS100 and Zoom Handy
Recorder H4n). For participants with CP±L, speech was audio recorded using a Zoom Handy
Recorder H4n and RØDE Microphone NT4-P48. Language samples were simultaneously
video recorded (JVC Pro HD Camera, GY-HM100E). For analysis of speech measures audio
recordings were used. CAS feature analysis of groping was based on video recordings.
3.3 ANALYSIS
Table 2 summarizes the different instruments used in studies II, III, and IV. As can be seen,
measures of speech were included in all three studies, whereas measures of orofacial
function, language and communication were used in study II and study IV respectively.
28
Table 2. Overview of measures analyzed, based on tests assessing speech, orofacial function, language and
communication and used in studies II, III and IV
Measures
Study
II
Study
III
Study
IV
Speech
Swedish Articulation and Nasality Test (SVANTE) (Lohmander et al., 2005)
Features commonly associated with CAS and their operational definitions (Iuzzini-
Seigel & Murray, 2017)
Percentage of Consonants Correct (PCC)
x
Percent Words Correct (PWC)
x
Inconsistency Severity Percentage of consonants and vowels
(ISPc and ISPv)
x
Number and type of CAS features
x
Intelligibility in connected speech rated by SLP
x
Orofacial function
Orofacial screening (NOT-S) (Bakke et al., 2007)
Orofacial function examination
x
Orofacial function interview
x
Language
Clinical Evaluation of Language Fundamentals (CELF-4) (Semel et al., 2003; Swedish
version, 2013)
Core Language Score
x
Expressive Language Index
x
Receptive Language Index
x
Communication
Children's Communication Checklist (CCC-2) (Bishop, 2003; Swedish translation, 2011)
Intelligibility in Context scale (ICS) (McLeod et al., 2012a; Swedish translation, 2012b)
General Communication Composite
x
Social Interaction Deviance Composite
x
Intelligibility in Context rated by parents
x
3.3.1 Measures of speech
3.3.1.1 Articulation
For study II, narrow phonetic transcription of targeted consonants was performed according to
IPA and ExtIPA conventions (IPA, 2005, 2008). For study III, semi-narrow phonetic
transcription of the whole words, consonants and vowels was performed (SVANTE;
Lohmander et al., 2005). The percentage of consonants correct score (PCC score) (Shriberg,
Aram, & Kwiatkowski, 1997; Shriberg & Kwiatkowski 1982) was based on the same single
word material but included different numbers of consonants for calculations in study II and III.
In study II, including children with CP±L only, PCC scores were based on narrow phonetic
transcription of 59 targeted consonants, with nasality variables subtracted, following the
29
routine speech registration at 5 years reported into the National Quality Registry for Cleft Lip
and Palate (https://lkg-registret.se/?page_id=96). For inclusion in study III and subsequently
study IV, the PCC score was based on semi-narrow transcription of the whole words (161
consonants) for all participants. The reported percentage of words correct (PWC) in study IV
was based on semi-narrow transcription of 161 consonants and 69 vowels. The calculation of
the inconsistency severity percentages for consonants and vowels (ISPc and ISPv respectively)
used in study III, was based on semi-narrow phonetic transcriptions of 112 consonants and 69
vowels.
3.3.1.2 Childhood apraxia of speech
For diagnosis of CAS, two SLPs jointly judged the presence or absence of the operationalized
12 CAS features (Iuzzini-Seigel & Murray, 2017). Ten features were judged perceptually using
the audio/video recordings of single words, whereas two features were calculated based on
semi-narrow phonetic transcriptions of the same single words.
3.3.1.3 Intelligibility
The assessing SLP rated to which degree connected speech was intelligible using a 3-point
ordinal scale (0 = good/normal, 1 = mildly reduced and 2 = moderately to severely reduced)
(SVANTE; Lohmander et al., 2005).
3.3.2 Measures of orofacial function
Scoring of the 12 domains was made on a binary scale (yes/no), that is 0 or 1 point per domain.
The maximum total test score of 12 would indicate difficulties within all tested domains (NOT-
S; McAllister & Lundeborg Hammarström, 2014).
3.3.3 Measures of language
Three subtests respectively are included in the expressive and receptive language indexes and
were scored live during assessment. The subtests included in the receptive index were scored
on a binary scale (correct/incorrect). The three subtests included in the expressive index all use
ordinal scales, although differing between binary, 3-point and 4-point ordinal scales. The
scoring of the three expressive subtests was controlled a second time, directly after assessment,
using the video recording. Consequently, the core language score was composed of a
combination of one receptive subtest score and the three expressive subtests scores (CELF-4;
Semel et al., 2003, Swedish version, 2013).
30
3.3.4 Measures of communication
Functional intelligibility was quantified using parental ratings of the degree to which their
child’s speech was understood in everyday life by themselves, immediate family members,
extended family members, friends, acquaintances, teachers and strangers on a 5-point scale (0
= never, 1 = rarely, 2 = sometimes, 3 = usually, 4 = always) (ICS; McLeod., et al., 2012a,
2012b).
Functional communication was quantified sorting the 70 parental questions into 10 subscales
representing different communication areas and calculating the frequency of subscale
behaviors rated by parents on a 4-point scale (0 = less than once a week or never, 1 = at least
once a week but not every day, 2 = once or twice a day, 3 = every day or always). Two index
scores, named the general communication composite and the social interaction deviance
composite, were calculated including several, thus different, of the subscales (CCC-2; Bishop,
2003, Swedish translation, 2011).
3.4 RELIABILITY
Reliability of transcriptions was calculated as point-by-point percentage agreement between
two transcribers. In order to be considered an agreement, the compared consonants had to be
identically transcribed for place, manner, and voicing. Vowels had to be identically transcribed
to be considered an agreement. In study II, the mean intra-transcriber agreement on 30% of
randomly chosen transcriptions of target consonants was calculated and resulted in 96% for the
main transcriber and 95% for the second transcriber. The mean inter-transcriber agreement
between the two transcribers based on 41% of target consonants was 92%. In study III the intra-
transcriber agreement for the main transcriber was based on 29% of the material including both
consonants and vowels, this is, randomly chosen re-transcriptions of ten children, including
five children from group sCAS and five from group CP±L. The mean intra-transcriber
agreement was 86% for consonants and 96% for vowels. Inter-transcriber agreement between
the two transcribers, the main transcriber and second transcriber from study II, was based on
re-transcription of the same 29% of the material, resulting in a mean inter-transcriber agreement
of 88% for consonants and 90% for vowels.
Reliability assessment of expressive language scoring in study IV was based on rescoring 30%
of randomly chosen recordings from both participant groups by a second SLP. The intraclass
31
correlation coefficient (ICC) was calculated for single measures with absolute agreement using
a two-way mixed model. ICC was .97 with a 95% confidence interval from .92 to .99.
3.5 STATISTICAL ANALYSES
Nonparametric statistics were chosen because of skewed data and small sample sizes. All
analyses were performed using SPSS (versions 23, 26) and for all statistical analyses, p < .05
(two tailed) was considered significant.
Results from study I and III were presented using descriptive statistics. In study II, correlations
between variables within the study group were tested with Kendall τB. The Mann-Whitney U
test was used to compare the study groups’ outcome measures with reference data. Differences
between subgroups in study II and IV were tested using the Mann-Whitney U test or Kruskal-
Wallis test, depending on the number of subgroups. In study IV, within-subgroup differences
between subtests were analyzed using the Wilcoxon signed-rank test.
3.6 ETHICAL APPROVALS
Ethical approval was obtained from the Regional Ethical Review Board in Stockholm, Sweden
for studies II-IV. The ethical approval for study II, with Dnr: 2014/609-31/2, was the main
approval. For studies III and IV, the same main approval and two supplements, Dnr: 2015/251-
32 and 2015/1305-32, used in both studies, were obtained. No application for ethical approval
was filed for study I. The anonymous participation when completing the questionnaire was one
reason for this choice, as was the content of questions asked, targeting professional know-how
and not patient-specific information. Participation in study I was consented to by responding
to the web-based questionnaire.
32
4 RESULTS
4.1 STUDY I
The SLPs selected seven main speech characteristics, from a list of 17, as typical for children
with CAS. These were: inconsistent speech production (85%), sequencing difficulties (71%),
oro-motor deficits (63%), vowel errors (62%), voicing errors (61%), consonant cluster deletion
(54%) and prosodic disturbance (53%). Underlying motor-programming difficulties were
perceived by 82%. Twenty-nine percent considered CAS as being a separate disorder, 10% as
a disorder cooccurring with another disorder, and 51% agreed with the alternative that there
are both clear cases of CAS as well as cases cooccurring with other disorders. The proposition
that children with CAS typically display phonological deficits was agreed on by 44%, and
cooccurring language disorder was perceived by 10% of the SLPs. The mode of the estimated
clinical occurrence of CAS in Swedish speaking pre- and primary school-aged children was
5%.
4.2 STUDY II
Orofacial dysfunction was found in 37% of children born with CP±L, which is significantly
more frequent compared to reference data for 5-year-olds (McAllister & Lundeborg
Hammarström, 2014) on children without CP±L. Age-appropriate articulation proficiency was
found in 39%, whereas 49% presented below 2 SD scores. Just above 50% had good
intelligibility and were always understood by different communication partners according to
both SLP and parent rating. No significant correlations were found between orofacial
dysfunction and PCC or between orofacial function and intelligibility. Compared to reference
data, sensory function and drooling were the domains where children born with CP±L were
significantly more affected than the reference group. However, the degree of impairment did
not differ between cleft types. Orofacial function was not different between children with CP±L
plus additional malformations compared to children with CP±L only. Children with CP±L plus
language disorder on the other hand had significantly more often difficulties within the domain
of oral motor function, compared to children without additional difficulties.
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4.3 STUDY III
A distinct CAS profile was shared by 12 of the 34 participants. The profile included phonemic
speech inconsistency for consonants and vowels plus vowel error, voicing error, difficulty
achieving initial articulatory configurations or transitionary movement gestures and stress
errors. This CAS profile met the three consensus-based ASHA criteria. Sixty-seven percent
(n=10) of children with sCAS were diagnosed with CAS, whereas 33% (n=5) had non-CAS
SSD. For group CP±L the corresponding figures were 11% (n=2) with CAS and 89% (n=17)
with non-CAS SSD. For participants with non-CAS SSD no specific speech profile was found,
and prosodic impairment was rare.
4.4 STUDY IV
Expressive language disorder was found in 67% of children diagnosed with CAS. Tasks
targeting morphological ability and verbatim repetition of sentences were particularly affected.
In all children with CAS, receptive language was significantly stronger than expressive
language, whereas no such difference was observed in the group of children with non-CAS
speech sound disorder (non-CAS SSD). Developmental language disorder, including
significant difficulties within both receptive and expressive domains, was found in 18% of
children with non-CAS SSD, while expressive language disorder was found in 9%. Parent
ratings of communication skills reflected an increased burden on communication in everyday
life when difficulties within both speech and language domains were present.
Figure 3. Participants in study IV and classification after assessment of language (study IV). sCAS, suspected
childhood apraxia of speech; CP±L, cleft palate with/without cleft lip; CAS, childhood apraxia of speech, DLD,
developmental language disorder; non-CAS SSD, speech sound disorder but not CAS.
Participants study IV sCAS CP±L
n=15 n=8
n=3 n= 7 n=3 n=2
n=1 n=1 n=5 n=1
Classification after CAS CAS+DLD non-CAS SSD non-CAS SSD+DLD
language assessment n=4 n=8 n=8 n=3
34
5 DISCUSSION
In this doctoral project, childhood apraxia of speech was explored from different perspectives:
the knowledge and praxis of CAS among SLPs was investigated and the speech and language
abilities of children with suspected CAS were examined. Results were also compared to
children with speech difficulties related to cleft palate, that is, a different but comparably severe
speech sound disorder, in order to explore the speech profile of CAS. Furthermore, explanatory
factors for unfavorable speech outcome in children born with CP±L, such as orofacial
dysfunction and language disorder, were examined.
5.1 A SPEECH PROFILE ASSOCIATED WITH CHILDHOOD APRAXIA OF
SPEECH
When comparing the views of SLPs on typical speech characteristics of CAS in English and
Swedish speakers, they corresponded in large. The most prevalent characteristic of CAS in all
surveys, study I included, was inconsistent production or inconsistency of errors (Forrest,
2003; Joffe & Pring, 2008; Meredith & Potter, 2011). There were no contradicting results found
for CAS speech characteristics between the studies on Swedish and English language contexts,
indicating that research could be valid cross-linguistically for the two languages. Swedish
SLPs’ top seven speech characteristics of CAS were inconsistent speech production (85%),
sequencing difficulties (71%), oro-motor deficits (63%), vowel errors (62%), voicing errors
(61%), consonant cluster deletions (54%) and prosodic disturbance (53%). Some of these
characteristics cannot not be translated directly into a feature from the 12-feature list used in
study III (Iuzzini-Seigel & Murray, 2017). However, these top speech characteristics reflect
the three ASHA diagnostic criteria (ASHA, 2007).
The cross-linguistic validity of CAS speech characteristics suggested in study I led to the design
of study III, aiming at evaluating a checklist for CAS constructed for English-speaking
children. When the work on this thesis project began, there were no evidence-based assessment
protocols or standardized tests available in Swedish, for differential diagnosis of CAS.
However, in 2016 the Swedish version and extension of the Dynamic Evaluation of Motor
Speech Skills (DEMSS; Strand & McCauley, 2019) was published (DYMTA; Rex, McAllister
& Hansson, 2016). In study III, a CAS speech feature list was investigated that was
operationalized by Iuzzini-Seigel and Murray (2017). This list has also been used in other
recent studies (e.g. Centanni, Green, Iuzzini-Seigel, Bartlett, & Hogan, 2015; Iuzzini-Seigel,
35
Hogan, Guarino, & Green, 2015a; Iuzzini-Seigel, 2019; Zuk et al., 2018). By replicating the
diagnostic procedure for CAS used in research on English-speaking children, we evaluated the
procedures applicability for diagnosis in another Germanic language. In addition, we
investigated the diagnostic relevance of the checklist by including two groups with disordered
speech of different origin and with some hypothesized overlap of speech characteristics.
The most prevalent characteristic of CAS, according to SLPs in study I and in line with earlier
surveys, was inconsistency of production errors (Forrest, 2003; Joffe & Pring, 2008; Meredith
& Potter, 2011). This was also the only mandatory CAS feature on the checklist used (Iuzzini-
Seigel, Hogan, & Green, 2017; Iuzzini-Seigel & Murray, 2017). For judgment of inconsistent
errors, the phonemic speech inconsistency was calculated based on phonetic transcription. The
calculation of the inconsistency severity percentage (ISP) (Iuzzini-Seigel et al. 2017) was
developed and advocated for its ability to differentiate suspected CAS from phonological
disorder in preschool children (Iuzzini, 2012; Iuzzini & Forrest, 2010). Speech inconsistency
was also used as a diagnostic marker and could differentiate between CAS and speech delay
(Iuzzini-Seigel et al., 2017). In studies on school-aged children, an ISP of 18% or higher on
production of sounds-in-words was proposed to distinguish children with CAS. The calculation
of the ISP was also promoted because of its clinical applicability, reusing transcriptions of a
custom word list or an articulation test already included in standardized test batteries (Iuzzini-
Seigel & Murray, 2017). Iuzzini-Seigel and colleagues (2017) concluded that speech
inconsistency can contribute to the differential diagnosis of school-aged children with CAS;
however, they emphasized the impact of stimuli selection on results. Further, they declared that
stimuli too simple for participants would not tax phonemic inconsistency. On the other hand,
stimuli too challenging for children with speech disorder would not be efficacious in
differentiating CAS from other speech disorders. In this project, inconsistency of phoneme
production in simple, single words was used owing to the severe speech disorder of the
participating 5-year-old children. This task was also perceived as relatively free from both
language load and higher-order planning; thus, results were hypothesized to primarily reflect
inconsistency of speech production due to CAS. Owing to the simple speech material used, ISP
results were lower than reported in studies using materials including challenging multisyllabic
words and non-words. When using this simpler speech material, the ISP for participants ranged
from 0 to 34% with just five participants (15%) scoring 0%, indicating no ceiling effect. To
determine a cut-off, in accordance to the 18% reported for older children using more complex
materials (Iuzzini-Seigel, 2012) the distribution of scores was examined. However, it did not
indicate a cut-off differentiating CAS from non-CAS SSD. Because inconsistent consonant and
vowel production is a prerequisite for a CAS diagnosis (ASHA, 2007), it is unclear why the
36
ISP reported so far has been calculated based on consonants only. Consequently, the
inconsistency severity percentage for vowels (ISPv) was constructed in analogy to the
calculation of the ISP for consonants (Iuzzini-Seigel et al., 2017). The ISPv calculated from
the simple, single word material ranged from 0 to 7% with 20 of all participants (59%) scoring
0%. Interestingly, all participants with the CAS feature profile (n=12) scored above 0%.
Additionally, one of the three participants with CP±L fulfilling the ASHA primary criteria, as
discussed in a following section, scored 3%. None of the participants classified as non-CAS
SSD presented with inconsistent vowel errors, making the ISPv a promising measure for further
validation.
The emerged CAS speech profile consisted of a distinct set of five features: the mandatory
speech inconsistency plus four features (vowel errors, voicing errors, difficulty achieving initial
articulatory configurations or transitionary movement gestures and speech errors), when
using Iuzzini-Seigel and Murray’s (2017) checklist and operationalized definitions. In other
words, of the possible 10 features from the list that could be evaluated within this project, five
(50%) were shared by all cases with CAS. However, for a CAS diagnosis according to Iuzzini-
Seigel and Murray (2017) an additional optional feature was needed. It should be noted that
the number of CAS features needed for a CAS diagnosis is arbitrary and differs between
research groups (e.g. studies of Iuzzini-Seigel and colleagues contra Shriberg and colleagues),
as does the frequency of occurrences of a specific feature needed to be considered for the
feature to be present. This means that the number of different features and the frequency of that
feature’s presence are two different measures, the first indicating variation in feature criteria
(e.g. ASHA’s three primary criteria), the latter the frequency of a feature observed. To my
knowledge, there has been no attempt made to quantify feature frequency related to severity of
the speech disorder. In this project, one observation of a CAS feature, agreed upon by both
raters, was enough for that feature to be judged as present (a procedure further discussed under
methodological considerations, see 5.5.3). The used procedure could, therefore, explain the
relatively high occurrence of several CAS features seen in all included participants having
disordered speech in common.
Exploring the possible cooccurrence of CAS in children with CP±L and severely disordered
speech led to intriguing findings. Despite the reduced number of CAS features assessed, from
12 to 10 (for the discussion of this methodological limitation, see 5.5.3), at the same time
keeping the cut-off for a positive diagnosis of CAS stable, two out of 19 children (11%) with
CP±L fulfilled diagnostic criteria for CAS. Another three children fulfilled the three consensus-
based ASHA criteria. They were thus short of one feature, not reaching the minimal number of
37
CAS features needed for a diagnosis according to Iuzzini-Seigel and Murray (2017). None of
the presumably five children with CP±L who met the ASHA criteria for CAS had a diagnosis
of 22q11.2DS, a syndrome known to include a high percentage of children with cooccurring
CAS (e.g. Shriberg et al., 2019). However, of the two children with CP±L+CAS one had
additional malformations as had two of the additional three who met ASHA criteria. These five
children with CP±L represented different cleft types and malformations.
The three CAS features representing inappropriate prosody and stress were not found in any
children with non-CAS SSD, except for the three cases with CP±L fulfilling the ASHA
criteria presented in the section above. This finding, upraising stress errors as a diagnostic
marker for CAS, is well in line with current research and understanding (e.g. Morgan &
Webster, 2018; Shriberg et al., 2017c).
The proportion of Swedish children with sCAS, classified as non-CAS SSD (33%) in study III,
was in agreement with earlier research. Murray and colleagues (2015), also used community-
based SLPs for referral and inclusion of Australian children with sCAS, diagnosing 32% with
non-CAS. Both studies add to the body of evidence indicating that CAS is suspected and
overdiagnosed in the general SSD population (e.g. Forrest, 2003; Shriberg et al., 2011) and in
different language contexts.
5.2 A LANGUAGE PROFILE ASSOCIATED WITH CHILDHOOD APRAXIA OF
SPEECH
The reported gap between receptive and expressive language competence in children with
CAS (e.g. Rosenbek & Wertz, 1972; Murray et al., 2019) was confirmed in study IV. The
proportion of children having an expressive language disorder (67%) was similar to the
reported proportions of Dutch and English-speaking children (46-82%) (Thoonen et al., 1997;
Lewis et al., 2004; Iuzzini, 2012; Vuolo and Goffman, 2018; Zuk et al., 2018; Murray et al.,
2019). Receptive language competence in children with CAS could be considered a relative
strength.
The most severely impaired language ability was expressive morphology and morphosyntax,
shared by all children with CAS+DLD in this project. However, here the influence of stimuli
tasks on the results needs to be considered. As outlined by Murray and colleagues (2019) when
assessing morphology, many articulatory challenging sounds are targeted, and speech
38
production is anticipated to include inconsistency due to CAS. In addition, children with CAS
have difficulties with increased word length and complexity as well as producing weak
syllables (Murray et al., 2015; Shriberg et al., 2011). For assessment of morphology in this
project the ‘Word Structure’ subtest (CELF-4; Semel et al., 2003, Swedish version, 2013) was
used. The task requires mainly one-word answers using a sentence completion format, targeting
production of grammatical morphemes in a simple phonological context. To ensure reliability,
this subtest was rescored immediately after testing and later by a second SLP to determine
agreement. Production did not need to be correctly pronounced but signaled. Interestingly,
results on the two subtests used for assessment of morphosyntax, ‘Recalling Sentences’ and
‘Formulated Sentences’, requiring formulating or recalling a full sentence, were somewhat less
impaired compared to the morphology task and to reference data. This finding is in line with
conclusions made by Murray and colleagues (2019), that the ‘Word Structure’ subtest included
more linguistic-based morphological errors than did results from the subtest using sentence
level sampling contexts in children with CAS.
The finding of an association with a morphological language deficit in CAS, as found in this
project and previously reported (Murray et al., 2019; McNeill & Gillon, 2013) could be
explained using the dual stream model of speech processing (e.g. Hickock & Poeppel, 2004,
2007; Poeppel, Emmorey, Hickock & Pylkkänen, 2012). The suggested dorsal stream’s
importance for both auditory-motor transcoding and syntactic analysis could explain the
cooccurrence of such difficulties. Structural correlates of the dorsal stream are the posterior
temporal, temporo-parietal and inferior frontal regions and their corresponding white matter
connections through the superior longitudinal and arcuate fasciculi. Fiori and colleagues (2016)
found that one of the subnetworks disrupted in CAS involved the left inferior frontal gyrus,
classically related to speech motor connectivity correlated with oral diadochokinesis, oromotor
skills, expressive grammar and lexical difficulties.
39
5.3 FUNCTIONAL COMMUNICATION ASSOCIATED WITH SEVERELY
DISORDERED SPEECH
Intelligibility is a term describing how successful a speaker manages to convey a message to
the listener. Functional intelligibility, as measured by the intelligibility in context scale (ICS)
(McLeod et al., 2012a, 2012b) is a complex concept taking different aspects of communication,
different listeners and everyday life into account (Lagerberg, Hellström, Lundberg, &
Hartelius, 2019). The ICS screening tool was used for children with CP±L to obtain a measure
of intelligibility when communicating with different communication partners in everyday life,
adding ecological validity. For the same reason these parental ratings were compared to SLP
ratings of overall intelligibility in connected speech. Intelligibility, rated by parents and SLPs,
were largely in agreement for both children with good intelligibility which were always
understood by different communication partners as for children with moderate to severe
reduced intelligibility which were never/rarely/sometimes understood during conversation.
About 50% of 5-year-old children with CP±L were always understood according to parental
rating and scores of these children were almost identical compared to ICS-scores reported for
children with no speech difficulties (McLeod et al., 2012a). The results indicate that parental
rating of functional intelligibility using the ICS for children with CP±L could reliably
differentiate between children with and without associated communication disorder. The ICS
was also used when assessing children with sCAS in this project; however, results for this
group have not yet been presented.
Another parental rating instrument, The Children’s Communication Checklist (CCC-2; Bishop,
2003; Swedish translation, 2011), targets functional communication in everyday life. It was
completed by parents of children with sCAS and children with CP±L, intended to add
ecological validity to the standardized language assessment by the SLP (Semel et al., 2003,
Swedish version, 2013). The questionnaire targeted the domains speech, language,
communication and pragmatic/social interaction skills. Speech was rated to cause the greatest
difficulties with communication in everyday live, which is in line with a previous study on
children with SMCP aged 5 to 12:8 (Boyce et al., 2019). In addition, interesting results were
found in the parental rating of Syntax, which was below -2 SD scores for all participants with
CAS+DLD (n=7). Parent responses demonstrated an awareness of their child’s deviant
production, and in fact, an ability to differentiate between speech and language difficulties
when answering questions about sentence structure and grammar. Consequently, marked
difficulties with morphology are in line with results from formal assessment and should be seen
as part of the language profile associated with CAS.
40
5.4 EXPLANATORY FACTORS FOR SPEECH OUTCOMES IN CHILDREN
WITH CLEFT PALATE ± LIP
In the project factors explaining the large variation in speech outcome in the heterogeneous
group of children born with CP±L were explored. Orofacial function (study II), speech features
typically associated with CAS (study III) and language competence (study IV) were examined.
Age-appropriate articulation proficiency was found in just 39% of children with CP±L, an even
lower proportion compared to the previously reported 48% in a study of 5-year-olds including
several cleft types and syndromes (Britton et al., 2014). Varying results between study II and
the National audit standard study from Great Britain and Ireland (Britton et al., 2014) could be
owing to different study sizes and/or different conceptions of the label “speech within normal
range.” In study II, reference data from children without clefts and a cut-off at - 1 SD were
applied to meet criteria for normal articulation proficiency. Moreover, articulation proficiency
correlated significantly with intelligibility in study II.
Prior to study II, orofacial function had not been examined and reported systematically for
children with CP±L. Orofacial dysfunction was found to be more frequent in 5-year-old
children born with CP±L (37%) compared to children born without cleft (11%) (McAllister &
Lundeborg Hammarström, 2014). However, the findings were mainly within non-speech areas,
such as breathing, drooling, chewing and swallowing. Consequently, when correlating
orofacial function and articulation proficiency (PCC) the results indicated that orofacial
dysfunction was not an explanatory factor for speech outcome in children born with CP±L.
Focusing on speech features commonly associated with CAS, when exploring the speech of
children with CP±L, resulted in interesting findings. They indicated that 11% (n=2) of children
with CP±L fulfilled criteria for CAS based on Iuzzini-Seigel and Murray criteria (2017). As
many as 26% (n=5) would have met the three primary ASHA criteria (ASHA, 2007). The dual
diagnosis of CP±L and CAS could in fact explain the unfavorable speech outcome in a
subgroup of children with CP±L including both children with and without additional
malformations.
Cooccurrence of language disorder in children born with CP±L was examined. In study II,
children with CP±L plus DLD were the subgroup with the lowest articulation proficiency
(16%). Information about cooccurring DLD for all children with CP±L was based on data from
the National Quality Registry for Cleft Lip and Palate (https://lkg-registret.se/?page_id=96).
Unfortunately, only a small proportion of children with CP±L and severe speech disorder
41
volunteered for inclusion in study IV and the assessment of language abilities. Results indicated
cooccurring DLD in two of the eight (25%) participants with CP±L. This suggests, that
cooccurring DLD could be a factor explaining unfavorable speech outcome in children with
CP±L.
5.5 METHODOLOGICAL CONSIDERATIONS
5.5.1 Participants
The representativeness of the sample of children with CAS and CP±L included in this project
presents a methodological dilemma. Owing to participant heterogeneity and relatively small
sample sizes, especially after subgrouping, group results could have been influenced by
atypical performance in a few participants. No genetic or neuropsychiatric tests were conducted
of the participants. The ability to participate in formal testing was a prerequisite, although
several children within both included patient groups had attention difficulties, although
undiagnosed at the time. Three children needed an extra visit for test completion and a fourth
child two additional visits. On the other hand, the inclusion of a relatively unselected group of
children with cooccurring additional malformations or undiagnosed neuropsychiatric disorders
increase the samples clinical representativeness. Inclusion of a narrow age range minimized
age-driven changes as confounders. On the other hand, results might not be generalizable to
other age groups.
5.5.2 Phonetic transcription
Although narrow phonetic transcription has been advocated for highly unintelligible speech
(e.g. Ball, Müller, Klopfenstein, & Rutter, 2009), semi-narrow transcription of single words
was performed. This was motivated because transcription in finer detail than needed is not time
efficient. Moreover, there needs to be a balance between level of detail in transcription and
reliable and replicable intra- and inter-transcriber agreement used in research to facilitate
methods to be transferable into clinical settings (Heselwood & Howard, 2008).
42
5.5.3 Diagnostic procedure
When directly replicating a method, one should follow the original parameters as close as
possible (for a discussion of study replication, see Zwaan, Etz, Lucas, & Donnellan, 2018). In
this project the diagnostic procedure proposed by Iuzzini-Seigel and Murray (2017) was
replicated, using definitions, operationalized features and diagnostic cut-offs as required for
CAS diagnosis. Despite failure to rate two out of the 12 features from the checklist in this
project, the cut-off was retained, thereby changing the proportion of speech features needed for
a CAS diagnosis. Iuzzini-Seigel and Murray (2017) specified six (one mandatory plus five
optional features) of the twelve that equal 50% of the total number of features. For children
with CP±L in this thesis this resulted in six of ten features (60%). Consequently, there could
have been three additional children with CP±L included in the CAS group had we used the
50% cut-off. Thus, as many as 26% of children with CP±L could potentially have cooccurring
CAS, or at least several speech features indicating difficulties with speech motor planning and
control.
Replicating the use of just one occurrence of a specific feature as evidence of the presence of
that feature, was questioned by the two raters. Research on the development of speech motor
control has shown that boys until age 5 experience a slower maturational course of speech
motor development. After a plateau between the ages of 7 to 12, adultlike speech motor
processes are used from age 14 and upwards (Smith & Zelaznik, 2004). This knowledge about
typically later maturation of speech abilities makes it questionable to apply just one incorrect
production as an indicator for presence of a CAS speech feature, especially in 5-year-olds.
However, different diagnostic procedures have used different speech tasks and cut-offs for the
number of CAS features needed for a diagnosis (e.g. Shriberg et al., 2011). The specific aim of
this project was to evaluate a checklist, constructed for speakers of another language (Iuzzini-
Seigel & Murray, 2017) and parameters thus had to be replicated as closely as possible.
43
6 CONCLUSIONS
• Swedish SLPs had relevant theoretical and/or clinical knowledge about CAS, but often
reported a need for further education (Study I).
• Findings suggested cross-linguistic applicability of CAS speech feature definition and
operationalization between English and Swedish speakers (Studies I and III).
• Swedish-speaking 5-year-olds with CAS shared a distinct speech profile including the
five features: speech sound inconsistency of consonants and vowels, vowel error,
voicing error, difficulty achieving initial articulatory configurations or transitionary
movement gestures and stress errors (Study III).
• Prosodic impairment was seen almost exclusively in children with CAS but not in
children of the same age with other SSDs (Study III).
• In children with CP±L and SSD, a hightened cooccurrence of CAS should be
anticipated (Study III).
• There was a consistent gap between worse expressive and better receptive language
ability in children with CAS, not seen in children with non-CAS SSD. Expressive
language disorder should be expected in more than half of children with CAS (Study
IV).
• Poor articulation proficiency in children with CP±L, was not related to orofacial
dysfunction. The high prevalence of orofacial dysfunction was related to drooling and
impaired sensory function (Study II).
• Parental ratings of communication abilities in everyday life both added ecological
validity to formal assessment and confirmed formal findings (Studies II and IV).
44
7 CLINICAL IMPLICATIONS
The goal of clinical research is to accelerate and improve the development and delivery of
services provided after implementing research findings into clinical practice. How this is best
accomplished within the field of communication sciences and disorders has recently been
addressed in a tutorial by Douglas and Burshnic (2019). The proposed means are within the
framework of implementation science, focusing on the direct collaboration between clinicians
and researchers to lessen the gap between research and practice. In this project I transferred
from the role of curious and frustrated clinician to researcher and am now obligated and
determined to find ways to further clinical implementation. Having one foot in research and
one within clinical practice could facilitate collaboration and exploring different means for
implementation. Results from study I indicated that the majority of SLPs (83%) had actively
been searching for information on their own, acknowledging the need for lifelong learning as
part of their professional development. Possibly, an implementation workshop with SLPs, in
analogy to the one described by Shrubsole and colleagues (2018), could influence practice
change in a positive way. Targeting different domains including knowledge, beliefs about own
capabilities and consequences as well as addressing barriers for the implementation such as
lack of time and leadership, could raise awareness of potential difficulties and facilitate
implementation of differential diagnosis of SSDs and diagnosis of CAS in particular.
Identifying children in need for SLP assessment and/or intervention could be aided by using
the quick ICS screening tool, in study II shown to be reliable for rating a child’s intelligibility
(for more information about the ICS validity and reliability, see McLeod, 2020). Children born
with CP±L are enrolled in a cleft palate team in Sweden, with scheduled routine visits to a SLP
at ages 1.5, 3, 5, 7, 10, 16 and 19 years. Perhaps, regularly distributing a screening tool such as
the ICS between visit-years during the preschool and early school years, could engage parents
continuously reflecting over their child’s communicative ability and be profitable for both
clinicians and parents. This has already been suggested and included in the International
Consortium for Health Outcomes Measurement (ICHOM) standard set at ages 5, 12 and at final
visit (Allori et al., 2017). Another way to make use of the ICS is in bilingual children. The ICS
has been translated into over 60 languages (https://www.csu.edu.au/research/multilingual-
speech/ics) and could be used to compare a child’s intelligibility in both spoken languages
before engaging an interpreter, for further assessment, if needed.
45
Including the orofacial screening tool (NOT-S, Bakke et al., 2007), used in study II, into routine
visits at age 5 could be a time effective and easy way to identify the higher proportion of
children with orofacial dysfunction and guide interventions focusing on difficulties with
breathing, drooling, chewing and swallowing.
For children with CP±L, awareness about possible cooccurrence of speech difficulties
including CAS should be anticipated in children with severe disorder at age 5 years.
The cooccurrence of expressive language disorder in more than half of children with CAS
and several with CP±L, stresses the need for language assessment for all children with
suspected CAS and severe SSD. Assessment of children with difficulties to cooperate could
be aided by using information from a parental checklist, such as the CCC-2 (Bishop, 2011).
46
8 FUTURE STUDIES
Larger scale and longitudinal research approaches, including several age-groups and
participants with mild to severe CAS or SSD, are needed to corroborate the speech and
language profiles found in this study. Research collaborations and cross-linguistic studies,
using the same protocols to expand participant numbers, could be profitable. Research
collaborations within Sweden could do the same, working towards a standard set and national
guidelines for diagnosis of children with CAS.
Developing a comprehensive screening instrument, combining the speech and language feature
profiles found for CAS in this project, could help bridging the gap between research and clinic.
In addition, parental ratings of intelligibility and communication in everyday life could be part
of the screening procedure. Parental ratings in this project were found to be in line with SLP
assessment, and to be both time effective and adding ecological validity. The goal of such a
screening instrument could be twofold, both to assist in the identification of suspected CAS
patients and patients difficult to assess or classify, in need for referral to a specialized SLP.
Vowel inconsistency, and the inconsistency severity percentage of vowels (ISPv) proposed in
this project, may have potential as an exclusive marker of CAS. However, this needs to be
explored further. Future studies should also include languages with less complex vowel
systems compared to Swedish.
Another line of future research should focus on severity of CAS and an increased understanding
of the relative contribution of different speech features influence on intelligibility. To explore
which one of the CAS speech features influences speech intelligibility the most could be of
great value with direct clinical implications, aiding decisions about which treatment plan goals
to prioritize.
47
9 ACKNOWLEDGEMENTS
This work would not have been possible without the support and contributions from a great
number of people. I wish to express my sincere gratitude to:
Anette Lohmander, who agreed to be my main supervisor ‘if there were children with cleft
palate involved’. Thank you for your professional supervision and guidance; for being
inspiring, reliable, brilliant, patient and frank. You made me grow and I am so glad you have
grown some interest in childhood apraxia of speech as I have had the privilege to discover
and appreciate the cleft area.
Anita McAllister, co-supervisor with vast knowledge and experience within multiple areas.
Thank you for being supportive, inspiring and believing in me.
Per Östberg, who became my main supervisor after the half-time. Thank you for your
guidance and sharing knowledge about theoretical frameworks, methodology and statistics.
Sofia Strömbergsson, co-author and valuable reviewer of the thesis, thank you for your
brilliant yet unpresuming comments and suggestions.
Elisabeth Lundström, my employer at the Medical unit, Speech and Language Pathology,
Karolinska University Hospital. Thank you for your supportive and friendly advice and
enabling me to combine research with clinical work.
Liv Thalén, friend, former fellow PhD student and colleague. Thank you for sharing all ups
and downs during the PhD-journey. I am so grateful for our discussions about methodology,
statistics and ethics – not to forget our ‘Tea for two’-breaks and your loyal support at all
times.
Åsa Mogren and Susanne Rex, fellow PhD students and friends, for sharing significant
methodological discussions and headaches within our common area of research and for all
geeky good times. Looking forward to future collaborations! Susanne, thank you for time-
consuming consensus judgements.
Emilie Hagberg for participation in both assessment and time-consuming transcriptions and
in addition, for your interest and handling the clinical work with CAS patients. Hoping for
future collaborations!
Jill Nyberg, Emilie Hagberg, Tove Movérare, Liisi Raud Westberg and Katrin Stabel-
Svensson, dear former colleagues at the Craniofacial team at Karolinska University Hospital.
Thank you for the splendid collaboration, making space for me and my project and helping to
combine and facilitate clinical work with research interests. A special thanks to you, Liisi, for
the fine illustrations.
48
All fellow PhD students for conversations and especially research seminars, HÖST-retreats
and the instructive journey to Canada and Illinois in 2016: Anna Nyman, Anna Persson,
Annika Szabo Portela, Ineke Samson, Marion Lieberman, Jill Nyberg, Joakim Körner
Gustafsson, Susanne Rex, Åsa Mogren, Helena Hybbinette and Liv Thalén.
All colleagues at the Division of Speech and Language Pathology, at Karolinska Institutet.
Thank you for showing interest in my work: Kerstin Johansson, Päivikki Aarne, Ellika
Schalling, Anna Eva Hallin, Ulrika Nygren, Maria Södersten and Svante Granqvist.
A special thanks to Kicki Hedestedt, Anna Peterson and Agneta Wittlock for always rapidly
and kindly helping with the numerous challenges of administration.
All my friends and/or colleagues, near and far away, none mentioned, and none forgotten!
My family, always on my mind and surrounding me with love:
Jan, my husband and best friend since 1985. This project has consumed a lot of time and
occupied my thoughts, yet you have been my greatest supporter, tack älskling!
My son Henrik and wife Evelina, grandsons Benjamin and Alexander. You have opened your
home and welcomed me, thank you! Spending time with the boys is the most rewarding and
lovely experience and relaxation.
My daughter, Charlott, thank you for being close and truly understanding my urge for
research.
My parents, Mutter and Vater, thank you for choosing me, adopting and loving me and letting
me grow. Ich liebe Euch!
This research was financially supported by Majblommans Riksförbund,
the Aina Börjeson Foundation for Speech Language Pathology Research
and Treatment, the Foundation Frimurare Barnhuset, Stockholm, the
Stockholm County Council and Karolinska Institutet
49
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