Assessment and treatment of articulation and phonological disorders pdf

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assessment and treatment of articulation and phonological disorders pdf

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View larger. A must-have reference, this classic book delivers exceptional coverage of clinical literature and focuses on speech disorders of unknown causes. Offering a range of perspectives, it covers the normal aspects of speech sound articulation, normal speech sound acquisition, the classification of and factors related to the presence of phonological disorders, the assessment and remediation of speech sound disorders, and phonology as it relates to language and dialectal variations. This edition features twelve manageable chapters, including a new chapter on the classification of speech sound disorders, an expanded discussion of childhood apraxia of speech, additional coverage of evidence-based practices, and a look at both motor-based and linguistically-based treatment approaches.

Assessment of Articulation and Phonological Processes

Thus, in many current SSD classification systems the complex relationships between the etiology distal , processing deficits proximal and the behavioral levels speech symptoms is under-specified Terband et al. It is critical to understand the complex interactions between these levels as they have implications for differential diagnosis and treatment planning Terband et al.

There have been some theoretical attempts made towards understanding these interactions e. Specifically, we discuss how the AP model can provide an explanatory framework for understanding SSDs in children. Although other theories may be able to provide alternate explanations for some of the issues we will discuss, the AP framework in our view generates a unique scope that covers linguistic phonology and motor processes in a unified manner.

The theory-neutral term Speech Sound Disorders SSDs is currently used as a compromise to bypass the constraints associated with the articulation versus phonological disorder dichotomy Shriberg, The present definition describes SSD as a range of difficulties producing speech sounds in children that can be due to a variety of limitations related to perceptual, speech motor, or linguistic processes or a combination of known e.

The history of causality research for childhood SSDs encompasses several theoretically motivated epochs Shriberg, While the first epoch ss was driven by psychosocial and structuralist views aimed at uncovering distal causes, the second epoch s to s was driven by psycholinguistic and sociolinguistic approaches and focused on proximal causes. The more recent third and fourth epochs reflect the utilization of advances in neurolinguistics s and human genome sequencing post-genomic era; s and these approaches address both distal and proximal causes Shriberg, With these advances, several different systems for the classification of SSD subtypes in children have been proposed based on their distal or proximal cause e.

However, a critical problem in these classification systems as noted by Terband et al. For example, the links between the etiology distal; e. Thus, there is a critical need to understand the complex interactions between the different levels that ultimately cause the observable speech symptoms McAllister Byun and Tessier, ; Terband et al. There have been several theoretical attempts at integrating phonetics and phonology in clinical S-LP.

In this context, the characterization of speech patterns in children either solely as the product of performance limitations i. The authors discuss this approach using several examples related to the neutralization of speech sounds in word onset with primary stress positions.

They argue that positional velar fronting in these positions where coronals sounds are substituted for velar in children is said to result from a combination of jaw-dominated undifferentiated tongue gesture e.

In the present paper, we intend to reconcile the phonetic-phonology dichotomy and discuss the interconnectedness between these levels and the nature of SSDs using an alternative perspective.

We discuss articulatory gestures within the broader concepts of the Articulatory Phonology model AP; Browman and Goldstein, Although, other theoretical approaches e. There are other speech production models, but as argued in a recent paper, the majority of those are more similar to the Task Dynamics TD framework Saltzman and Munhall, in that they address specific issues related to the motor implementation stages with or without feedback and not so much include a principled account of phonological principles, such as formulated in AP Parrell et al.

This section on Articulatory Phonology AP; Browman and Goldstein, lays the foundation for understanding speech sound errors in children diagnosed with SSDs from this specific perspective. The origins of the AP model date back to the late s, when researchers at the Haskins laboratories developed a unique and alternative perspective on the nature of action and representation called the Task Dynamics model TD; Saltzman and Munhall, This model was inspired by concepts of self-organization related to functional synergies as derived from the Dynamical Systems Theory DST; Kelso, Various aspects of DST have been studied and applied in a diverse range of disciplines such as meteorology e.

Recently, there has also been an uptake of DST informed research related to different areas in cognitive and speech-language sciences, including language acquisition and change Cooper, ; language processing Elman, ; development of cognition and action Thelen and Smith, ; Spencer et al. The role of DST in speech and language sciences, in particular with respect to speech disorders, is still somewhat underdeveloped, mainly because of the challenges related to applying specific DST analyses to the relatively short data series that can be collected in speech research van Lieshout, However, we chose to focus on the AP framework, as it directly addresses issues related to phonology and articulation using DST principles related to relative stable patterns of behaviors attractor states , that emerge when multiple components neural, muscular, biomechanical underlying these behaviors interact through time in a given context self-organization as shown in the time varying nature of the relationship between coupled structures synergies that express those behaviors Saltzman and Munhall, ; Browman and Goldstein, This means that these sub components interact and function as a coordinated unit where patterns emerge and dissolve spontaneously based on self-organization, that is, without the need of a pre-specified motor plan Turvey, These patterns are generated due to internal and external influences relating to inter-relationships between the sub components themselves, and the constraints and opportunities for action provided in the environment Smith and Thelen, Such principles of pattern formation and coupling have already been demonstrated in physical e.

Haken et al. Specifically, a synergy in the context of movement is defined as a functional assembly of sub components e. In motor control literature, the concept of coordinative structures or functional synergies are typically modeled as non-linear oscillatory systems Kelso, ; Newell et al. For movement control, the synergy tuning process occurs with development and learning or may change due to task demands or constraints e. With regards to speech production, perturbation paradigms similar to the ones used in other motor control studies have demonstrated critical features of oral articulatory synergies e.

Functional synergies in speech production comprise of laryngeal and supra-laryngeal structures tongue, lips, jaw coupled to achieve a single constriction location and degree goal. Perturbing the movement of one structure will lead to compensatory changes in all functionally coupled structures including the articulator that is perturbed to achieve the synergistic goal Kelso and Tuller, For example, when the jaw is perturbed in a downward direction during a bilabial stop closure, there is an immediate compensatory lowering of the upper lip and an increased compensatory elevation of the lower lip Folkins and Abbs, The changes in the nature and stability of movement coordination patterns i.

Relative phase values are expressed in degrees or radians, and the standard deviation of relative phase values can provide an index of the stability of the couplings Kelso, ; van Lieshout, For example, changes in movement rate may destabilize an existing coordination pattern and result in a different coordination pattern as observed during gait changes such as switching from a walk to a trot and then a gallop as a function of required locomotion speed Hoyt and Taylor, ; Kelso, For speech, such distinct behavioral patterns as a function of rate have not been established.

This can be considered a characteristic of an efficient synergy. The same study also included people who stutter and reported more instances of not showing reduced covariance in this group, in line with the notion that stuttering is related to limitations in speech motor skill van Lieshout et al. Recent work has provided more insights regarding cortical networks in control of this coordination between speech articulators Bouchard et al. Chartier et al. Similar to limb control studies that discovered single motor cortical neurons that encoded complex coordinated arm and hand movements Aflalo and Graziano, ; Saleh et al.

That is, activity in the vSMC reflects the synergies used in speech production rather than individual movements. Interestingly, the study found four major clusters of articulatory kinematic trajectories that encode the main vocal tract configurations labial, coronal, dorsal, and vocalic necessary to broadly represent the production of American English sounds. The encoded articulatory kinematic trajectories exhibited damped oscillatory dynamics as inferred from articulatory velocity and displacement relationships phase portraits.

These findings support theories that envision vocal tract gestures as articulatory units of speech production characterized by damped oscillatory dynamics [ Fowler et al. The notion of gestures at the level of speech perception has been discussed in the Theory of Direct Perception Fowler, ; Fowler and Rosenblum, This theory posits that listeners perceive attributes of vocal tract gestures, arguing that this reflects the common code shared by both the speaker and listener Fowler, , , ; Fowler and Rosenblum, These concepts are supported by a line of research studies which propose that the minimal objects of speech perception reflect gestures realized by the action of coordinative structures as transmitted by changes to the acoustic and visual signal, rather than units solely defined by a limited set of specific acoustic features Diehl and Kluender, ; Fowler and Rosenblum, ; Fowler, The Direct Perception theory thus suggests that speech perception is driven by the structural global changes in external sensory signals that allow for direct recognition of the original gesture source and does not require special speech modules or the need to invoke the speech motor system Fowler and Galantucci, Having a common unit for production and perception provides a useful framework to understand the broader nature of both sensory and motor involvement in speech disorders.

For example, this can inform future studies to investigate how problems in processing acoustic information and thus perceiving the gestures from the speaker, may interfere with the tuning of gestures for production during development. Similarly, issues related to updating the state of the vocal tract through somato-sensory feedback a critical component in TD; Saltzman and Munhall, ; Parrell et al.

In this section, we will discuss the development and refinement of articulatory synergies and how these processes facilitate the emergence of speech sound contrasts.

Observational and empirical data from several speech motor studies as discussed below were synthesized to create the timeline map of the development and refinement of speech motor control and articulatory synergies as illustrated in Figure 1. Articulatory synergies in infants have distinct developmental schedules.

Speech production in infants is thought to be restricted to sounds primarily supported by the mandible MacNeilage and Davis, ; Davis and MacNeilage, ; Green et al. Vowel productions in the first year are generally related to low, non-front, and non-rounded vowels; implying that the tongue barely elevates from the jaw, and there is limited facial muscle lip interaction i.

Figure 1. Data driven timeline map of the development of speech motor control and articulatory synergies. For instance, young children are unable to coordinate laryngeal voicing gesture with supra-laryngeal articulation and hence master voiced consonants and syllables earlier than voiceless ones Kewley-Port and Preston, ; Grigos et al.

In children, up to and around 2 years of age, there is limited fine motor control of jaw height or jaw grading and weak jaw-lip synergies during bilabial production, but relatively stronger inter-lip spatial and temporal coupling Green et al. Observation of such a reduction in degrees of freedom in emerging synergies has been observed in other non-speech systems Bernstein, This process is observed to occur between the ages of 2 and 3 years Stoel-Gammon, ; Green et al.

Green et al. Control of this dimension also coincides with the emergence of coronal consonants e. By 4 years of age, all front and back vowels are within the spoken repertoire of children, suggesting a greater degree of control over jaw height and improved tongue-jaw synergies Kent, Intriguingly, front vowels and lingual coronal consonants emerge relatively late Wellman et al.

This is possibly due to the fine adjustments required by the tongue tip and blade to adapt to mandibular angles. Since velar consonants and back vowels are produced by the tongue dorsum, they are closer to the origin of rotational movement i. The later development of refined tongue movements is not surprising, since the tongue is considered a hydrostatic organ with distinct functional segments e.

Gaining motor control and coordinating the tongue with neighboring articulatory gestures is difficult Kent, ; Smyth, ; Nittrouer, Cheng et al.

This contrasts with the earlier developing lip-jaw synergy reported by Green et al. By 4—5 years, synergies that use the back of the tongue to assist the tongue tip during alveolar productions are adult-like Noiray et al. The extent and variability of lingual vowel-on-consonant coarticulation between 6 and 9 years of age is greater than in adults; implying that children are still refining their tuning of articulatory gestures Nittrouer, ; Nittrouer et al. These findings suggest that articulatory synergies have varying schedules of development: lip-jaw related synergies develop earlier than tongue-jaw or within tongue-related synergies Cheng et al.

Most of this work has been done on intra-gestural coordination i. Variability of intra-gestural synergies e. Overall, these findings suggest that the development of speech motor control is hierarchical, sequential, non-uniform, and protracted. The specific goals of each gesture are defined as Tract Variables Figure 2 and relate to vocal tract constriction location labial, dental, alveolar, postalveolar, palatal, velar, uvular, and pharyngeal and constriction degree closed, critical, narrow, mid, and wide; Figure 2.

While constriction degree is akin to manner of production e. Figure 2. A schematic representation of the AP model with key components Nam and Saltzman, ; Goldstein et al. The targets of each Tract Variable are implemented by specifying the lower-level functional synergy of individual articulators e. The coordinated actions of the articulators toward a particular value target of a Tract Variable is modeled using damped mass spring equations Saltzman and Munhall, The variables in the equations specify the final position, the time constant of the constriction formation i.

For example, if the goal is to produce constriction at the lips bilabial closure gesture , then the distance between the upper lip and lower lip lip aperture is set to zero. The resulting movements of individual articulators lead to changes in vocal tract geometry, with predictable aerodynamic and acoustic consequences.

The flexibility within the functional articulatory synergy implies that the task-level goals could be achieved with quantitatively different contributions from individual articulatory components as observed in response to articulatory perturbations or in adaptation to the linguistic context in which the gesture is produced Saltzman and Kelso, ; Browman and Goldstein, ; Alfonso and van Lieshout, ; Gafos, In other words, the task-level goals are discrete, invariant or context-free, but the resulting articulatory motions are context-dependent Browman and Goldstein, Gestures are phonological primitives that are used to achieve linguistic contrasts when combined into larger sequences e.

Speech Sound Disorders in Children: An Articulatory Phonology Perspective

It is normal for young children to make speech errors as their language develops; however, children with an articulation or phonological disorder will be difficult to understand when other children their age are already speaking clearly. Articulation refers to making sounds. The production of sounds involves the coordinated movements of the lips, tongue, teeth, palate top of the mouth and respiratory system lungs. There are also many different nerves and muscles used for speech. Phonological disorders and phonemic awareness disorders the understanding of sounds and sound rules in words have been linked to ongoing problems with language and literacy.

To analyze speech and linguistic features in children with articulation disorder characterized by consonant and vowel phonological errors. Between February and June , children who showed articulation disorder were selected for the study. Based on comprehensive speech and language assessments, the subjects were classified into articulation dysfunction AD , or AD overlapping with language delay. Detailed information of articulation, including percentage of consonants correct PCC and normal percentage of variable consonants derived from the Assessment of Phonology and Articulation for Children test, were compared between the two groups. Totally, 55 children were diagnosed as AD and 62 as AD with language delay. Mean PCC was not significantly different between the two groups. In both groups, the acquisition order of consonants followed the universal developmental sequence.

Children in the experimental group diagnosed with Stuttering and classified to severity of disease through the Stuttering Severity Instrument Differences between groups were not statistically significant on the incidence of phonological processes. There is evidence that the group of stuttering children is more likely the presence of at least one phonological process. Stuttering is a speech fluency disorder manifested by involuntary disruptions in the flow of speech. A disorder affects the temporal characteristics of subsystems involved in speech production 1.

Speech problems – articulation and phonological disorders

Thus, in many current SSD classification systems the complex relationships between the etiology distal , processing deficits proximal and the behavioral levels speech symptoms is under-specified Terband et al. It is critical to understand the complex interactions between these levels as they have implications for differential diagnosis and treatment planning Terband et al. There have been some theoretical attempts made towards understanding these interactions e. Specifically, we discuss how the AP model can provide an explanatory framework for understanding SSDs in children.

AJOL and the millions of African and international researchers who rely on our free services are deeply grateful for your contribution. Your donation is guaranteed to directly contribute to Africans sharing their research output with a global readership. Skip to main content Skip to main navigation menu Skip to site footer. Keywords: Articulation disorders, phonological disorders, phonemes, intelligibility. Abstract Thirty regular school children with functional articulation and phonological disorders, aged 7; 0 to 17; 11, were involved in the study.

Sharynne McLeod, Ph. McLeod provides numerous resources on her web site from her research at Charles Sturt University in Australia. McLeod and her colleague, Dr.

Speech and Linguistic Features of Children With Articulation Disorder

Serves as the primary textbook for introductory courses in articulation and phonological disorders. It includes boxed questions about important information, case examples, and illustrations. Read more Please choose whether or not you want other users to be able to see on your profile that this library is a favorite of yours.

Communicative Disorders pp Cite as. Normal articulation is a series of complex actions. Accurate articulation requires exact placement, sequencing, timing, direction, and force of the articulators. These occur simultaneously with precise airstream alteration, initiation or halting of phonation, and velopharyngeal action.

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