Post on 28-Apr-2023
Journal of Medical Speech-Language Pathology
Volume 20, Number 4, pp. 100–105
Copyright © 2013 Delmar Cengage Learning
Dysarthria Syndromes in Adult Cerebral Palsy
Theresa Schölderle M.A., and Anja Staiger Ph.D.
Clinical Neuropsychology Research Group, Neuropsychological Clinic,
Hospital Bogenhausen München, Germany
Reneé Lampe Prof
Center for Cerebral Palsy München, Germany
Wolfram Ziegler Prof
Clinical Neuropsychology Research Group, Neuropsychological Clinic,
Hospital Bogenhausen München, Germany
Keywords: dysarthria, cerebral palsy, CP type, syndrome classification
Cerebral palsy (CP) is a neurologic disorder that results from damage to the infant brain. The
most common communication impairment in CP is dysarthria. There are inconsistent reports
of different dysarthria syndromes in the CP types (spastic, dyskinetic, and ataxic), and it
remains unclear if dysarthria syndromes of CP can be classified based on a classification
system established for dysarthrias acquired in adulthood.
Twenty-two adult patients with CP participated. Dysarthria was assessed using the
Bogenhausen Dysarthria Scales (BoDyS). Patients were further classified for their
dysarthria syndromes by three experts. The BoDyS profiles of three comparison groups of
spastic (stroke and progressive supranuclear palsy, spastic type), hyperkinetic ( Huntington’s
disease), and ataxic (hereditary ataxias) dysarthria acquired in adulthood underwent a
linear discriminant analysis. The resulting discriminant function coefficients were applied
to the BoDyS profiles of the CP participants to empirically classify their speech disorders.
The observed dysarthric patterns matched the expected syndromes of spastic, hyperkinetic,
and ataxic dysarthria. However, dysarthria syndromes dissociated with CP types in many
cases. The classification of speech impairment should therefore be conducted independently
from CP type.
INTRODUCTION
Cerebral palsy (CP) is a permanent disorder of
movement and posture caused by damage to
the infant brain (Rosenbaum, Paneth, Leviton,
Goldstein, & Bax, 2007). Besides sensory, cogni-
tive, and behavioral dysfunctions, communication
impairment frequently accompanies the motor
disorder, predominantly in the form of dysarthria
(Hunter, Pring, & Martin, 1991).
The neurologic classification of CP type is
based on the primary motor deficit affecting the
extremities. Spastic CP type accounts for 88% of
the cases; the other subtypes are dyskinetic CP
(7%) and ataxic CP (4%). This classification also
includes mixed CP types, in which the predominant
motor syndrome co-occurs with one of the other
two pathologies (Krägeloh-Mann & Cans, 2009).
It is assumed that the different underlying
pathomechanisms of motor disorders in CP types
equivalently inluence speech motor control and
correspondingly manifest in perceptually distinct
dysarthria syndromes. However, this remains
controversial (Ansel & Kent, 1992; Platt, Andrews, &
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DySARTHRIA SyNDRoMeS IN ADuLT CeReBRAL PALSy 101
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Samples were drawn from a larger collection of
speech probes covering different etiologies. These
patients were matched to the CP group by the
overall severity of dysarthria.
DYSARTHRIA ASSESSMENT
All speech samples were elicited using the
Bogenhausen Dysarthria-Scales (BoDyS; Nicola,
Ziegler, & Vogel, 2004). The BoDyS provide a
detailed profile of dysarthric symptoms on the
basis of expert ratings. Four different speech tasks
with varying cognitive and linguistic demands are
included: (1) spontaneous speech, (2) sentence
repetition, (3) reading, and (4) description of a
picture story. The four tasks are administered in
three trials each, resulting in 12 speech samples.
BoDyS offers two scoring levels, the BoDyS scales
and the BoDyS features. The BoDyS scales cover
nine important functional dimensions of speech:
respiration, pitch and loudness, voice quality, voice
stability, articulation, resonance, rate, fluency,
and modulation. each of these scales comprises a
number of BoDyS features representing speciic
dysarthric symptoms. The rate scale, for instance,
comprises the two features, slow and fast. Table 1
provides an overview of the nine BoDyS scales
and, as an illustration, two exemplary sets of
features.
each of the 12 speech samples is analyzed in a
stepwise procedure: First, the perceived features
are checked in a protocol listing the 33 BoDyS
features. Table 2 illustrates this procedure with an
example. In this case, strained-strangled voice was
Howie, 1980). To date, no systematic perceptual
classification of dysarthria syndromes in adult
patients with cerebral palsy (including mixed CP
type) has been made. It is also still unexplored
whether different dysarthria syndromes of CP,
if they occur, are comparable to the correspond-
ing dysarthria syndromes acquired in adulthood.
Because adult CP patients have a history of a
severely compromised motor speech acquisition,
their syndrome patterns could differ from the
patterns described in populations with dysarthria
acquired in adulthood after normal development.
The aims of this study were (1) to classify
dysarthria syndromes in cerebral palsy in relation
to corresponding dysarthria syndromes acquired
in adulthood and (2) to investigate if pathomecha-
nisms of motor disorder affecting the extremities
in different CP types have a comparable impact
on speech, manifesting in corresponding dysar-
thria syndromes.
METHODS
Patients
Twenty-two adult patients with a confirmed
diagnosis of CP participated in the study (18–56
years of age; 12 women and 10 men). All adult
patients who currently received regular treatment
for dysarthria at the Center for Cerebral Palsy,
Munich, Germany, were included. They were
examined for their motor deicit (i.e., CP type) by
a neurologist; patients with mixed CP type were
not excluded.
To empirically classify dysarthria in CP, there
were three comparison groups (n 5 10 each) with
dysarthria acquired in adulthood: group 1 with
spastic dysarthria diagnosed with the spastic form
of progressive supranuclear palsy1 (ages 58–80
years; three men, seven women), group 2 showing
hyperkinetic dysarthria in Huntington’s disease2
(ages 29–68 years; six men, four women),and
group 3 with ataxic dysarthria and Friedreich’s
ataxia3 (ages 16–71 years; six men, four women).
1With S. Lorenzl, Clinic for Neurology, Großhadern, Munich,
Germany and G. Mallien, Neurological Clinic Wandlitz, Germany.2With u. Mannsberger, Clinic for Psychiatry, university Graz,
Austria.3With L. Schöls, H. Ackermann, B. Brendel, Center of
Neurology, university of Tübingen, Germany.
TABLE 1. The BoDyS and the Corresponding Features
of the Scales’ Voice Quality and Fluency
Scales
(Severity, 0–4)
Features
(Frequency of Occurrence, 0–12)
Respiration
Aphonia
Breathy voice
Strained-strangled voice
Fluctuating voice quality
Pitch or loudness
Voice quality
Voice stability
Articulation
Resonance
RatePauses
IterationsFluency
Modulation
BoDyS 5 Bogenhausen Dysarthria Scales.
⎧⎪⎨⎪⎩
⎧⎨⎩
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102 JouRNAL oF MeDICAL SPeeCH-LANGuAGe PATHoLoGy, VoL. 20, No. 4
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articulation, intermittent hypo or/ hypernasality,
irregular stress pattern, pitch and loudness
fluctuations, voice tremor, and strained-strangled
voice. The weighted scores of the three compari-
son groups (n 5 30) on these features underwent
a linear discriminant analysis, with the two result-
ing discriminant functions serving as syndrome
classiiers.
Expert Classification
In addition, each participant with CP was classiied
on the basis of samples of the BoDyS tasks
spontaneous speech and sentence repetition, for her
or his dysarthria syndrome by three experienced
listeners who were blinded for the patients’
neurologic diagnoses of CP type. The listeners made
their decisions on the basis of their overall impression
of the patients’ speech. The spastic, laccid, hypoki-
netic, hyperkinetic, and ataxic syndromes were rated
independently for their participation in the dys-
arthric disorder. The listeners also rated the coni-
dence of their classiications. only ratings with high
confidence scores and consistent classifications in
at least two of the three listeners were used for the
analyses. The expert classiications were compared
with the empirical classiications of dysarthria syn-
dromes and with the neurologic classiications of CP
type, which were disclosed after all data analyses
had been completed.
RESULTS
Expert Classification of the Patients
with Cerebral Palsy
Nineteen patients were classified consistently
by at least two experts with high confidence.
The classified syndromes were spastic (n 5 14),
observed in each of the speech samples ( frequency
of occurrence 5 12), and pauses were observed in
eight samples (frequency of occurrence 5 8); the
other features were not observed.
Second, the degree of impairment is scored for
each of the nine BoDyS scales using a 5-point
rating from 0 5 “very severe impairment” to
4 5 “no impairment.” These severity ratings of the
BoDyS scales do not necessarily reflect the fre-
quency of occurrence of the corresponding BoDyS
features. For example, even if strained-strangled
voice can be observed constantly in every speech
sample (frequency of occurrence 5 12; see earlier
example), it can still occur in a mild form with the
average severity of the corresponding voice qual-
ity scale ranging around 3 (“mild impairment”).
For the purpose of this study, we used weighted
features as a measure. Therefore, relative frequen-
cies of occurrence of the BoDyS features (ranging
from 0 5 “not observed” to 1 5 “observed in each
of the 12 samples”) were weighted by the severity
ratings of the corresponding BoDyS scales to
obtain severity scores for all features.4 In the
earlier example, strained-strangled voice has
a weighted score of 1 (relative frequency of
occurrence [1], multiplied with the reverse voice
quality score of 4 – 3 5 1). The weighted features
were used in the analyses reported here.
Classification by Discriminant Functions
To develop an empirically based classiication of the
CP participants, eight of the BoDyS features with
the highest potential to differentiate the expected
dysarthria syndromes (spastic, hyperkinetic, ataxic)
were selected based on common descriptions of the
syndromes. The selected features were involuntary
vocalizations, luctuating voice quality, luctuating
TABLE 2. example of a BoDyS Protocol Including Voice Quality and Fluency Features
Scales Features Frequency of Occurrence (1–12)
Voice quality Aphonia
Breathy voice
Strained-strangled voice X X X X X X X X X X X X
Fluctuating voice quality
Fluency Pauses X X X X X X X X
Iterations
BoDyS 5 Bogenhausen Dysarthria Scales.
4Severity scales had to be reversed in these weightings.
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DySARTHRIA SyNDRoMeS IN ADuLT CeReBRAL PALSy 103
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were stronger and more frequent in hyperkinetic
dysarthria.
Classification of the Patients with Cerebral
Palsy by Discriminant Functions
The discriminant function coeficients were then
applied to the BoDyS features of the CP partici-
pants to empirically map their dysarthria syn-
dromes onto the patterns of the three comparison
groups. The results of the classiication are shown
in Figure 2. A total of 86% (19 of the 22 patients)
were assigned to one of the three groups of dysar-
thria syndromes with a probability greater than
90%. The remaining three patients could not be
classified definitely; they were assigned to one
dysarthria syndrome with a probability less than
80% and to another with greater than 10% prob-
ability. Among the 19 patients classified with a
probability greater than 90%, 10 matched the pat-
tern of spastic dysarthria, six were allocated to
the ataxic group, and three were allocated to the
hyperkinetic group.
Comparison of Expert and Statistical
Classification of Patients with Cerebral Palsy
Sixteen patients were classified definitely by
both the expert ratings (high confidence scores
and agreement in at least two listeners) and the
hyperkinetic (n 5 3), and ataxic (n 5 1), and
one patient was diagnosed with mixed spastic-
hyperkinetic-ataxic dysarthria.
Statistical Reclassification of
the Comparison Groups
In a linear discriminant analysis, 93% of the
patients of the comparison groups were reclassiied
correctly; only two patients with HD were misclas-
siied as having ataxic dysarthria. Among the two
discriminant functions, the irst loaded highest on
the BoDyS features strained-strangled voice, luc-
tuating voice quality, and luctuating articulation
and showed a signiicant canonical correlation of
r 5 0.92 (P < .001). By this discriminant function,
the spastic group was separated from the other two
groups (Figure 1). Whereas the spastic patients
scored high on the feature strained-strangled
voice, the hyperkinetic and ataxic groups scored
high on luctuating voice quality and luctuating
articulation. Regarding the second discriminant
function fluctuating voice quality, fluctuating
articulation and involuntary vocalizations attained
high loadings (canonical correlation r 5 0.69;
P 5 0.01). This function differentiated between
hyperkinetic dysarthria and ataxic dysarthria
(see Figure 1). Whereas luctuating voice quality
and luctuating articulation received higher scores
in the ataxic group, involuntary vocalizations
Spastic
Ataxic
Hyperkinetic
Discriminant function I
Discrim
inant function II
–4 –2 420
–4
–2
0
4
2
6
–6
HD
PSP
FA
Figure 1. Reclassification of the comparison groups by
a linear discriminant analysis. FA 5 Friedreich’s ataxia;
HD 5 Huntington’s disease; PSP 5 progressive supra-
nuclear palsy.
Spastic
Ataxic
Hyperkinetic
Discriminant function I
Discrim
inant function II
–4 –2 0 42
–4
–2
0
4
2
6
–6
Comparison
groups
CP
Figure 2. Classification of the patients with cerebral
palsy (CP) by discriminant analysis.
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104 JouRNAL oF MeDICAL SPeeCH-LANGuAGe PATHoLoGy, VoL. 20, No. 4
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neurologic classiications of CP types agreed in 13 of
the 19 cases. In six patients (three spastic, one dys-
kinetic, one ataxic, and one mixed spastic-dyskinetic
CP type), the dysarthria syndrome did not it with
the CP type (Figure 3). In four of these six cases, the
statistical classiication of the dysarthria syndrome
was in agreement with expert ratings. The two
other cases, both classiied as ataxic dysarthria by
the discriminant analysis, were also rated as ataxic
by the experts yet with low conidence scores.
discriminant analysis (probability .90%). In 13
(81%) of these patients, the two classifications
were consistent.
Comparison of Statistical Classification
of Dysarthria with Cerebral Palsy Type
The classiications of dysarthria syndromes based
on the discriminant analysis (including only
patients classiied with a probability .90%) and the
Spastic
Ataxic
Hyperkinetic
Discriminant function I
Discrim
inant function II
–4 –2 420 0
–4
–2
0
4
2
6
–6
*
Spastic
Ataxic
Hyperkinetic
Discriminant function I
Discrim
inant function II
–4 –2 42
–4
–2
0
4
2
6
–6
*
Discriminant function I
Discrim
inant function II
–4 –2 420
–4
–2
0
4
2
6
–6
Spastic
Ataxic
Hyperkinetic
*
Spastic
Ataxic
Hyperkinetic
Discriminant function I
Discrim
inant function II
–4 –2 420
–4
–2
0
4
2
6
–6
*
*
*
Spastic CP type
Ataxic CP type
Dyskinetic CP type
Spastic-dyskinetic
CP type
Figure 3. Classification of dysarthria syndromes (by discriminant analysis) as a function of cere-
bral palsy (CP) type; dissociations are marked with asterisks.
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DySARTHRIA SyNDRoMeS IN ADuLT CeReBRAL PALSy 105
Submit a manuscript online – www.cengage.com/community/JMSLP
Address Correspondence to Theresa Schölderle, M. A.,
Entwicklungsgruppe Klinische Neuropsychologie Dachauer
Str 164 80992, Muenchen, Germany, PHONE: 149 89
154057, FAX: 149 89 156781
e-mail: Theresa.Schoelderle@extern.lrz-muenchen.de
REFERENCES
Ansel, B. M., & Kent, R. D. (1992). Acoustic-phonetic
contrasts and intelligibility in the dysarthria
associated with mixed cerebral palsy. Journal of
Speech and Hearing Research, 35, 296–308.
Hunter, L., Pring, T., & Martin, S. (1991). The use of
strategies to increase speech intelligibility in cerebral
palsy: An experimental evaluation. International
Journal of Language & Communication Disorders,
26, 163–174.
Krägeloh-Mann, I., & Cans, C. (2009). Cerebral palsy
update. Brain & Development, 31, 537–544.
Nicola, F., Ziegler, W., & Vogel, M. (2004). Die
Bogenhausener Dysarthrieskalen (BoDyS): ein
Instrument für die klinische Dysarthriediagnostik.
Forum Logopädie, 2/18, 14–22.
Platt, L. J., Andrews, G., & Howie, P. M. (1980).
Dysarthria of adult cerebral palsy: II. Phonemic
analysis of articulation errors. Journal of Speech
and Hearing Research, 23, 41–55.
Rosenbaum, P., Paneth, N., Leviton, A., Goldstein, M., &
Bax, M. (2007). A report: the definition and
classification of cerebral palsy. Developmental
Medicine & Child Neurology, 109, 8–14.
DISCUSSION
Dysarthria in CP can be classiied based on pat-
terns of symptoms similar to dysarthrias acquired
in adulthood. The observed symptoms matched
the predicted dysarthria syndromes (spastic, hy-
perkinetic, ataxic), and the features included in
the two discriminant functions corresponded to
expectations (e.g., strained-strangled voice as an
indicator of spastic dysarthria). The patient clas-
sification obtained in the discriminant analysis
was also conirmed by expert ratings in the major-
ity of cases.
There were dissociations between dysarthria
syndromes and CP types. Accordingly, dysarthria
syndromes do not allow conclusions regarding the
pathomechanisms underlying the motor disorder
of the extremities. This might be attributable to
varying inluences of complex motor pathomecha-
nisms on body and speech motor function or may
indicate compensatory adaptation in speech. As-
sessment of dysarthria in cerebral palsy should
therefore consider aspects beyond syndrome clas-
sification such as functional mechanisms and
communication impairment.
Acknowledgment The irst author was supported
by a PhD fellowship from the German National
Academic Foundation. We would like to thank the
speech-language-therapists at the Center for Cerebral
palsy, München and are grateful to all the participants
of the study. We also thank the ReHa-Hilfe e.V. for their
support.
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