PPT

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Ray Kent SymposiumRay Kent Symposium

Differentiating Motor Differentiating Motor Planning & Phonologic Planning & Phonologic

Impairment in Severe Impairment in Severe Speech DisordersSpeech Disorders

Edy Strand

Department of Neurology

Associate Professor, Mayo College of Medicine

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Purpose - ScopePurpose - Scope

Task:

Speak on the topic of differentiating motor planning & phonologic impairment in severe speech sound disorders in children

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In our hour today:In our hour today: Definitions and Descriptions of phonologic

impairment versus motor speech impairment (apraxia versus dysarthria)

Discussion of diagnostic markers Discussion of issues that influence our clinical

thinking in differential diagnosis Review of Assessment Tasks Interpretation of observations toward coming

to a differential diagnosis

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Purposes of Purposes of AssessmentAssessment(McNeil & Kennedy, 1984)(McNeil & Kennedy, 1984)

Screening – Detect or confirm a problem requiring further assessment

Differential Diagnosis

Specify severity and prognosis

Plan Treatment

Measure change that occurs as a result of treatment

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Severe Speech Sound Disorders


Phonologic Impairment Motor Speech Impairment

CASDysarthria




CASDysarthria




CASDysarthria




CASDysarthria




CASDysarthria




CASDysarthria

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Phonology –Phonology – The term phonological disorders is frequently

used to refer to the entire range of developmental communication disorders in which sound production is principally affected.

Specifically, phonologic disorders are a subset of sound production disorders in which linguistic and cognitive factors are thought to be central to the observed difficulties.

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Childhood Apraxia of SpeechChildhood Apraxia of Speech (CAS)(CAS) CAS is a speech disorder, due to delays or

deviances in those processes involved in planning and programming movement sequences for speech.

Children with CAS will have difficulty reaching and maintaining specific articulatory configurations, as well as difficulty moving from one articulatory configuration to the next.

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Unless they have a coexisting dysarthria, they will not have difficulty moving muscles with the correct range, speed and force for non-speech activity, including chewing or swallowing.

Respiration and phonation will be unimpaired as the primary difficulty is planning movement to reach articulatory configurations.

While a great many of these children also have linguistic (phonologic, semantic, syntactic) deficits, the term “apraxia” relates to their movement difficulties.

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DysarthriaDysarthria

This is a collective term for a group of related motor speech disorders resulting from disturbed muscular control of the speech mechanism.

Dysarthria is manifest as disrupted or distorted oral communication due to paralysis, weakness, abnormal tone or incoordination of the muscles used in speech.

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Processes of phonation, respiration, resonance, articulation and prosody are affected.

Movements may be impaired in force, timing, endurance, direction and range of motion.

In some types of dysarthria involuntary movements (dyskinesias) occur, disrupting articulatory output.

Sites of lesion include bilateral cortical damage; cranial nerves involvement; spinal nerve involvement (respiration); basal ganglia and cerebellum.

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Dysarthria CharacteristicsDysarthria Characteristics

Slurred speech Imprecise articulatory contacts Weak respiratory support and low volume Incoordination of the respiratory stream Hypernasality Involuntary dyskinesias of the oral facial

muscles Spasticity or flaccidity of the oral facial

muscles

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What do we do to come to What do we do to come to a differential diagnosis?a differential diagnosis?

Review the history, examine the structure and function of the speech mechanism, and observe habitual speech/language skill

Form clinical hypotheses regarding the nature of the speech disorder

Test those hypotheses through our specifically chosen and/or constructed assessment tasks

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Assessment tasks allow us to make observations of: Spontaneous speech and language Elicited speech

Standardized tests Non standardized tasks or measurements

Tally, describe, or measure aspects of speech production

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Compare speech characteristics observed with: Normative data Developmental scales Accepted diagnostic (behavioral) markers for

specific categories of speech disorders

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Diagnostic MarkersDiagnostic Markers

Diagnostic markers:

Physiologic markers: (e.g. Ach receptor antibodies for MG)

Behavioral Markers: observed in habitual performance observed in carefully controlled contexts

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No physiologic markers for many diagnoses:

dementia autism schizophrenia SLI learning disabilities asthma

These diagnoses are made primarily by clinical observation and meeting a number of clinical inclusionary and/or exclusionary criteria.

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Diagnostic Markers – Motor Diagnostic Markers – Motor Planning versus Phonologic Planning versus Phonologic Impairment Impairment For years, the literature repeatedly noted “no

consensus” regarding accepted characteristics of CAS

This was considered a very controversial diagnostic label

When one read the literature, however, very similar descriptions were given by most people.

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Diagnostic Markers in Diagnostic Markers in CASCAS There was one important area of disagreement While many described CAS as a motor planning

disorder, and did not include linguistic parameters in the inclusionary criteria for the label

Others have included linguistic deficits (e.g.

phonemic sequencing errors) as part of the description of the disorder (e.g. Aram & Nation, 1982; Lewis et al, 2004; Shriberg et al., 1997a,b,c; Velleman, 1994)

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The behavioral characteristics that have been

suggested for the identification of motor

planning impairment (CAS) over the years

may be useful as potential behavioral/clinical

markers:

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Speech Characteristics - CASSpeech Characteristics - CAS Difficulty with achieving initial articulatory

configurations

Difficulty moving from one articulatory configuration to another

Groping and/or trial and error behavior

Presence of vowel distortions

Limited consonant and vowel repertoire

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Speech Characteristics - CASSpeech Characteristics - CAS

Use of simple syllable shapes

Frequent omission of sounds

Increased errors with increased word length and phonetic complexity

Difficulty completing a movement gesture for a phoneme easily produced in a simple context, but not in a longer one

Connected speech poorer than isolated word production

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Markers Essential to the Markers Essential to the PhenotypePhenotype Difficulty achieving and maintaining articulatory

configurations

Presence of vowel distortions

Altered suprasegmentals lexical and sentential stress overall prosodic contours

Altered timing between sounds and syllables

Inconsistent error patterns

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ASHA position statement: ASHA position statement: CASCAS CAS is a neurological childhood speech sound

disorder in which the precision and consistency of movement underlying speech are impaired in the absence of neuromuscular deficits

Features consistent with a deficit in the planning and programming of movements for speech Inconsistent consonant and vowel errors Lengthened and disrupted coarticulatory transitions Inappropriate prosody

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So far – we’ve reviewed: How to approach coming to a differential

diagnosis of motor planning impairment The behavioral diagnostic markers for CAS

Lets take a brief look at some of the issues that

affect our clinical thinking in differential diagnosis of motor planning versus phonologic impairment in children with speech sound disorders.

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Many issues influence our Many issues influence our clinical thinking in differential clinical thinking in differential diagnosis of MSDdiagnosis of MSD

#1. Theoretical perspectives regarding the co-emergence of language and movement in speech acquisition

#2. Knowledge base

#3. Previous work and current practices in nosology/classification

#4. Clinical Issues - Current clinical practices

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#1. Theoretical issues regarding #1. Theoretical issues regarding the co-emergence of language the co-emergence of language and movement in speech and movement in speech acquisitionacquisition

This is not a new discussion

“As best as I can tell, you and I agree that models of language formulation and speech production have had a relatively independent coexistence. Developments in one area have had rather small impact in the other. What I’d like you to do is the following”:

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a) Identify major constructs that you believe to hold promise for the amalgamation of these two classes of models

b) Suggest how the major contemporary models of speech production differ in their relation to models of language formulation

c) Consider the prospects for change. What will it take to stimulate interaction between language theorists and speech production theorists?

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Co-emergence of language Co-emergence of language and movementand movementA number of researchers have addressed

this issue of how language and speech interact during development (e.g. Smith and Goffman, 2004; Stockman, 2004; Kent, 2004; Strand, 2002)

This impacts differential diagnosis in a number of ways

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For example…For example… Kent, (1984) noted that development of speech must

be understood in relation to language structures on one hand, and the organization of movement sequences on the other.

He posited a theory that was based in terms of musculoskeletal and neural maturation, (rather than in terms of conventional linguistic contrasts)

His theory described speech development with a system designed to reflect articulatory movement and vocal tract anatomy – which changes during this period of acquisition

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Kent, (2004) argued for the notion that cognition exerts strong influences on speech motor control which should be viewed as a cognitive-motor accomplishment.

He cited evidence from the motor learning literature to show the cognitive influences on motor performance and learning

He cited neurophysiologic evidence that motor systems are activated by observing or imagining movement

And, he noted that both perceptual and motor learning are affected by cognitive and emotional context

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Smith and Goffman (2004)

They ask: How can we relate the physiology of muscle activation to the units of language?

They note that there is no single level of linguistic processing acting at the language motor interface – this makes modeling hard

They posit that bidirectional influences of language and motor factors interact – and change over time

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#2 Using the Knowledge #2 Using the Knowledge BaseBase

Neuromotor and structural development Kent (1999) Motor Control: Neurophysiology & Functional Development Kent, (1976; 1990; 1991; 1992; 1995)

Cognitive and language development Phonological development The use of evidenced based practice

to judge validity and reliability as well as the sensitivity and specificity of our measures

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Our understanding of theoretical constructs as well as a broad knowledge base impacts our actions and decisions in differential diagnosisHow we construct assessment tasksOur development of new standardized testsOur choices among tests already available

(for that specific child and our clinical hypotheses regarding the nature of that child’s speech disorder)

How we interpret observations made over different contexts

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#3. #3. Nosology/ClassificationNosology/ClassificationThis has been the topic of research in

childhood speech disorders for some time: (e.g. Dodd, 1995; Shriberg,1994; 2003)

Not trivial – “label” reflects underlying impairment which mandates a particular type of treatment approach

This is particularly relevant to differential diagnosis of motor planning impairment, as there had been a lack of agreement about the characteristics associated with the CAS classification

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#4. Current clinical #4. Current clinical practicespracticesa) Review some of the literature regarding

measurements that may be helpful toward the determination of differential diagnosis

b) Review basic assessment procedures for differential diagnosis

c) Comment on standardized tests currently available and their psychometric adequacy

d) Argue for more dynamic assessment in motor speech disorders

e) Review some data regarding the construct validity of a new dynamic measure of motor speech skill

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a) Measurement that may be a) Measurement that may be helpful to differential helpful to differential diagnosis of MSD in Kidsdiagnosis of MSD in Kids

Maximum Performance Tests (MPT)(Kent, Kent & Rosenbek, 1987) MPTs examine the upper limits of performance for speech

tasks Their review summarized the published normative data,

identified primary task variables and provided guidelines for data interpretation

Other researchers have also contributed to this literature including Rvachew, Hodge & Ohber, 2005; Thoonen et al, 1999; Potter, 2007)

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Acoustic and physiological measures of variability (e.g. Shriberg, Green, Campbell, Mcsweeny, & Scheer, 2003;

Smith & Goffman, 1998),

Duration (e.g. Shriberg, Campbell, Karlsson, Brown, Mcsweeny, & Nadler, 2003)

Temporal spatial patterns (e.g., Gibbon, 1999; Moore, 2001; Murdoch, Attard, Ozanne, & Stokes, 1995; Nijland, Maassen, van der Meulen, Gabreels, Kraaimaat, & Schreuder , 2003).

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Application of some of these methods has led to the identification of subtle motor involvement among a wider range of children with speech abnormalities, including those with specific language impairment

(Goffman, 1999) and articulation/phonologic disorder for whom motor

speech involvement had not necessarily been suspected (Gibbon, 1999).

These measures may prove increasingly useful in the examination of speech and nonverbal oral movements in young children – and therefore be helpful in differential diagnosis of motor planning as well as movement execution impairment.

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b) Clinical Procedures in b) Clinical Procedures in AssessmentAssessment History

Language Assessment

Sound System Description Independent analysis (assessment of the child’s system

independent of the adult system Relational analysis (assessment of the child’s system in

relation to the target (adult) system

Assessment of the Motor systems

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Assessment of Motor Assessment of Motor SystemsSystems Examination of Neuromuscular Condition

Structural functional Exam

Motor Speech Examination

Examination of Physiological subsystems

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Motor Speech Exam Motor Speech Exam (MSE)(MSE)Allows the clinician to observe changes in

performance associated with variations in linguistic and motor complexity.

And, is probably the most appropriate tool for determining the presence of motor planning and programming deficits (CAS)

Allows one to examine behavioral markers when the child is trying to imitate movement gestures for specific utterances

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Motor Speech Motor Speech ExaminationExaminationExamine the child’s ability to sequence

movement for phonetic sequences in various contexts

Vowels CV VC CVC Monosyllabic, bisyllabic, polysyllabic Phrase Sentences of increasing length

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MSE – An MSE – An Argument for Argument for Dynamic TestingDynamic Testing

A dynamic approach to testing motor speech skill will facilitate determining severity, prognosis, and help with treatment planning.

Cues: Tactile Temporal

slow rate Vary the temporal relationship between the stimulus

and the response

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Motor Speech Motor Speech ExaminationExaminationDirect Imitation (if wrong) Simultaneous,

slower movement

Simultaneous (if wrong) Tactile cues

Simultaneous (if right) Direct Imitation

Direct Imitation (if right) Add delay

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Motor Speech Motor Speech ExaminationExaminationThis varying the temporal relationship is just a

“TOOL” to determine:

How much help does the child need to reach the articulatory configuration and move into the subsequent ones –Severity

Helps determine what phonetic segments, syllabic shapes, and length the stimuli should be

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Standardized Tests for Motor Standardized Tests for Motor Speech SkillSpeech SkillThere are only a few standardized

measures of motor speech skill currently available (McCauley & Strand, in press)

Vary in content and scope Most are limited in psychometric adequacy Only one examines the effect of visual and

tactile cueing on the child’s response and then for fewer than half of the test items

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DEMSSDEMSS Strand, McCauley & Stoeckel (2004; in preparation)

demonstrated initial construct validity and reliability for a new dynamic motor speech examination: The Dynamic Evaluation of Motor Speech Skill

Purpose – Facilitate differential diagnosis of motor planning and

programming deficits for speech production (CAS) Determine severity and prognosis for improvement

Focuses solely on motor speech skill Systematically varies the length, vowel content, syllable

shapes, prosodic content, and phonetic complexity within the utterances sampled

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DEMSSDEMSS

The test examines parameters frequently associated with the diagnosis of apraxia of speech Movement accuracy Vowel production Consistency Prosody

The test uses a multidimensional scoring system to examine the child’s response to different levels of cueing

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DEMSSDEMSS

In order to demonstrate the construct validity of this test, we have previously reported the results of a hierarchical agglomerative Cluster Analysis, using the DEMSS accuracy, vowel, prosody, and consistency scores, as variables.

Purpose - identify groups of children with similar profiles of performance on the DEMSS

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SubjectsSubjects 82 Consecutive children between the ages of 36 and

71 months who were referred for speech evaluations at the Mayo Clinic for concerns regarding speech deficits.

Exclusionary Criteria structural deficits (e.g., cleft palate) hearing loss ESL autism developmental delay beyond MMI

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ProcedureProcedureAll children completed a comprehensive testing

battery Receptive Language Testing Expressive Language Testing Language Sample

MLU phonetic and phonemic inventories observations re grammar and syntax

Structural Functional Exam Test for Oral Non-Verbal Praxis Articulation Testing DEMSS

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ProcedureProcedure

A diagnosis was made at the time of testing, based on all observations (including those made during administration of the DEMSS)

However, DEMSS subscores and total scores were not calculated until later and were not used in making the diagnosis.

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Hierarchical Agglomerative Hierarchical Agglomerative Nesting Cluster AnalysisNesting Cluster Analysis

Algorithm starts with each study subject forming his or her own cluster

For each pair of clusters a measure of “dissimilarity” is calculated.

The two most “similar” clusters are then merged together.

The algorithm repeats until there are only two remaining clusters and stops after merging these two clusters into one single cluster consisting of all subjects.

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DEMSSDEMSS That study was a first step in an effort to develop a

valid, reliable and dynamic tool to diagnose deficits in planning and programming movement gestures for volitional speech production in children.

We are now Completing an item analysis as part of a revision of the

instrument We want to follow the lead of Dr. Kent and others and include

some measures of maximum performance Repeat studies to demonstrate construct validity and reliability Establish normative data

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Interpretation of Interpretation of Assessment DataAssessment DataOften very difficult

Interaction of language and speech in acquisition

Coexisting disorders Complicated syndromes Seeing the child at only one point in time

Interpretation of Interpretation of Assessment DataAssessment DataBut – we have tools to help Theoretical perspectives regarding the co-

emergence of language and movement in speech acquisition

Knowledge base Neuromotor and structural development Cognitive and language development Phonological development

Previous work and current practices in nosology/classification

Determining Differential Determining Differential DiagnosisDiagnosisClinical Decision Making We use those tools in interpreting

assessment data to confirm or disprove our clinical hypotheses regarding the nature of the communicative disorder

We consider the response patterns and behavioral markers (spontaneous & elicited from the child) and compare them with those associated with the different classifications or labels of speech disorder type

Determining Differential Determining Differential DiagnosisDiagnosis One must also consider the relative

contribution of linguistic (phonologic) and motor impairment and how that impacts the child’s speech acquisition

One can then plan the focus of treatment, as well as treatment methods according to that relative contribution.

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In ConclusionIn Conclusion Differential Diagnosis is much more than

assigning a label

The clinician’s challenge is to use a broad knowledge base with best standards of clinical practice to guide clinical decisions and determine the relative contribution of linguistic and motor impairment

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Luckily, Dr. Kent has helped us by greatly added to the knowledge base

He has provided a great deal of insight and perspective in this endeavor.

Thank you, Ray!Thank you, Ray!

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speech activity

phonologic disorders

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