Developmental verbal dyspraxia

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Developmental verbal dyspraxia
Other namesSpeech and language disorder with orofacial dyspraxia

Developmental verbal dyspraxia (DVD), also known as childhood apraxia of speech (CAS) and developmental apraxia of speech (DAS), [1] is a condition in which an individual has problems saying sounds, syllables and words. This is not because of muscle weakness or paralysis. The brain has problems planning to move the body parts (e.g., lips, jaw, tongue) needed for speech. The individual knows what they want to say, but their brain has difficulty coordinating the muscle movements necessary to say those words. [2]

Contents

The exact cause of this disorder is usually unknown. [1] Many observations suggest a genetic cause of DVD, as many with the disorder have a family history of communication disorders. [1] [3] [4] [5] The gene FOXP2 has been implicated in many studies of the condition, and when this is the cause, the condition is inherited in an autosomal dominant manner, however roughly 75% of these cases are de novo . [6]

There is no cure for DVD, but with appropriate, intensive intervention, people with this motor speech disorder can improve significantly. [7]

Presentation

"Childhood apraxia of speech (CAS) is a neurological childhood (pediatric) speech sound disorder in which the precision and consistency of movements underlying speech are impaired in the absence of neuromuscular deficits (e.g., abnormal reflexes, abnormal tone). CAS may occur as a result of known neurological impairment, in association with complex neurobehavioral disorders of known or unknown origin, or as an idiopathic neurogenic speech sound disorder. The core impairment in planning and/or programming spatiotemporal parameters of movement sequences results in errors in speech sound production and prosody." American Speech-Language-Hearing Association (ASHA) Ad Hoc Committee on Apraxia of Speech in Children (2007) [7]

There are three significant features that differentiate DVD/CAS from other childhood speech sound disorders. These features are:

Even though DVD/CAS is a developmental disorder, it will not simply disappear when children grow older. Children with this disorder do not follow typical patterns of language acquisition and will need treatment in order to make progress. [7]

Causes

DVD/CAS is a motor disorder, which means that the problem is located in the brain and its signals, and not in the mouth. [8] In most cases, the cause is unknown. Possible causes include genetic syndromes and disorders. [8]

Recent research has focused on the significance of the FOXP2 gene [9] [10] [11] [12] [13] in both species and individual development. [14] Research regarding the KE family, where half the members of the extended family, over three generations, exhibited heritable developmental verbal dyspraxia, were found to have a defective copy of the FOXP2 gene. [4] [15] and further studies suggest that the FOXP2 gene as well as other genetic issues could explain DVD/CAS. [9] [16] including 16p11.2 microdeletion syndrome. [17] [18]

New research suggests a role for the sodium channel SCN3A in the development of the perisylvian areas, which maintain key language circuits- Broca and Wernicke Area. [19] Patients with mutations in SCN3A had oral-motor speech disorders. [19]

Birth/prenatal injuries, as well as stroke, can also be causes of DVD/CAS. Furthermore, DVD/CAS can occur as a secondary characteristic to a variety of other conditions. These include autism, [1] some forms of epilepsy, [1] fragile X syndrome, galactosemia [1] [20] and chromosome translocations [14] [21] involving duplications or deletions. [16] [22]

Diagnosis

Developmental verbal dyspraxia can be diagnosed by a speech–language pathologist (SLP) through specific exams that measure oral mechanisms of speech. The oral mechanisms exam involves tasks such as pursing lips, blowing, licking lips, elevating the tongue, and also involves an examination of the mouth. A complete exam also involves observation of the patient eating and talking. Tests such as the Kaufman Speech Praxis test, [23] a more formal examination, are also used in diagnosis. [23] A differential diagnosis of DVD/CAS is often not possible for children under the age of two years old. Even when children are between 2–3 years, a clear diagnosis cannot always occur, because at this age, they may still be unable to focus on, or cooperate with, diagnostic testing. [24]

Management

There is no cure for DVD/CAS, but with appropriate, intensive intervention, people with the disorder can improve significantly. [7]

DVD/CAS requires various forms of therapy which varies with the individual needs of the patient. Typically, treatment involves one-on-one therapy with a speech–language pathologist (SLP). [8] In children with DVD/CAS, consistency is a key element in treatment. Consistency in the form of communication, as well as the development and use of oral communication are extremely important in aiding a child's speech learning process.[ citation needed ]

Many therapy approaches are not supported by thorough evidence; however, the aspects of treatment that do seem to be agreed upon are the following:

Although these aspects of treatment are supported by much clinical documentation, they lack evidence from systematic research studies. In ASHA's position statement on DVD/CAS, [7] ASHA states there is a critical need for collaborative, interdisciplinary, and programmatic research on the neural substrates, behavioral correlates, and treatment options for DVD/CAS.

Integral stimulation

One technique that is frequently used to treat DVD/CAS is integral stimulation. Integral stimulation is based on cognitive motor learning, focusing on the cognitive motor planning needed for the complex motor task of speech. It is often referred to as the "watch me, listen, do as I do" approach and is founded on a multi-step hierarchy of strategies for treatment. This hierarchy of strategies allows the clinician to alter treatment depending upon the needs of the child. It uses various modalities of presentation, emphasizing the auditory and visual modes. Experts suggest that extensive practice and experience with the new material is key, so hundreds of target stimuli should be elicited in a single session. Furthermore, distributed (shorter, but more frequent) and random treatment, which mix target and non-target utterances, produces greater overall learning.[ citation needed ]

The six steps of the hierarchy upon which integral stimulation therapy for children is loosely organized are:

Integrated phonological approach

Another treatment strategy that has been shown to have positive effects is an integrated phonological approach. This approach "incorporates targeted speech production practice into phonological awareness activities and uses letters and phonological cues to prompt speech production". [26] McNeill, Gillon, & Dodd studied 12 children ages 4–7 with DVD/CAS who were treated with this approach two times a week for two six-week blocks of time (separated by a six-week withdrawal block). They found positive effects for most of the children in the areas of speech production, phonological awareness, word decoding, letter knowledge, and spelling. These results show that it is clinically productive to target speech production, phonological awareness, letter knowledge, spelling, and reading all at once. This is particularly important since children with DVD/CAS often have continuous problems with reading and spelling, even if their production of speech improves. [26]

See also

Related Research Articles

A communication disorder is any disorder that affects an individual's ability to comprehend, detect, or apply language and speech to engage in dialogue effectively with others. This also encompasses deficiencies in verbal and non-verbal communication styles. The delays and disorders can range from simple sound substitution to the inability to understand or use one's native language. This article covers subjects such as diagnosis, the DSM-IV, the DSM-V, and examples like sensory impairments, aphasia, learning disabilities, and speech disorders.

<span class="mw-page-title-main">Apraxia</span> Medical condition

Apraxia is a motor disorder caused by damage to the brain, which causes difficulty with motor planning to perform tasks or movements. The nature of the damage determines the disorder's severity, and the absence of sensory loss or paralysis helps to explain the level of difficulty. Children may be born with apraxia; its cause is unknown, and symptoms are usually noticed in the early stages of development. Apraxia occurring later in life, known as acquired apraxia, is typically caused by traumatic brain injury, stroke, dementia, Alzheimer's disease, brain tumor, or other neurodegenerative disorders. The multiple types of apraxia are categorized by the specific ability and/or body part affected.

Speech disorders or speech impairments are a type of communication disorder in which normal speech is disrupted. This can mean fluency disorders like stuttering, cluttering or lisps. Someone who is unable to speak due to a speech disorder is considered mute. Speech skills are vital to social relationships and learning, and delays or disorders that relate to developing these skills can impact individuals function. For many children and adolescents, this can present as issues with academics. Speech disorders affect roughly 11.5% of the US population, and 5% of the primary school population. Speech is a complex process that requires precise timing, nerve and muscle control, and as a result is susceptible to impairments. A person who has a stroke, an accident or birth defect may have speech and language problems.

<span class="mw-page-title-main">FOXP2</span> Transcription factor gene of the forkhead box family

Forkhead box protein P2 (FOXP2) is a protein that, in humans, is encoded by the FOXP2 gene. FOXP2 is a member of the forkhead box family of transcription factors, proteins that regulate gene expression by binding to DNA. It is expressed in the brain, heart, lungs and digestive system.

Expressive language disorder is one of the "specific developmental disorders of speech and language" recognised by the tenth edition of the International Classification of Diseases (ICD-10). As of the eleventh edition, it is considered to be covered by the various categories of developmental language disorder. Transition to the ICD-11 will take place at a different time in different countries.

Specific language impairment (SLI) is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development, physical abnormality of the speech apparatus, autism spectrum disorder, apraxia, acquired brain damage or hearing loss. Twin studies have shown that it is under genetic influence. Although language impairment can result from a single-gene mutation, this is unusual. More commonly SLI results from the combined influence of multiple genetic variants, each of which is found in the general population, as well as environmental influences.

Speech delay, also known as alalia, refers to a delay in the development or use of the mechanisms that produce speech. Speech – as distinct from language – is the actual process of making sounds, using such organs and structures as the lungs, vocal cords, mouth, tongue, teeth, etc. Language delay refers to a delay in the development or use of the knowledge of language.

<span class="mw-page-title-main">Speech–language pathology</span> Disability therapy profession

Speech–language pathology (also known as speech and language pathology or logopedics) is a healthcare and academic discipline concerning the evaluation, treatment, and prevention of communication disorders, including expressive and mixed receptive-expressive language disorders, voice disorders, speech sound disorders, speech disfluency, pragmatic language impairments, and social communication difficulties, as well as swallowing disorders across the lifespan. It is an allied health profession regulated by professional bodies including the American Speech-Language-Hearing Association (ASHA) and Speech Pathology Australia. The field of speech-language pathology is practiced by a clinician known as a speech-language pathologist (SLP) or a speech and language therapist (SLT). SLPs also play an important role in the screening, diagnosis, and treatment of autism spectrum disorder (ASD), often in collaboration with pediatricians and psychologists.

<span class="mw-page-title-main">Developmental coordination disorder</span> Medical condition

Developmental coordination disorder (DCD), also known as developmental motor coordination disorder, developmental dyspraxia or simply dyspraxia, is a neurodevelopmental disorder characterized by impaired coordination of physical movements as a result of brain messages not being accurately transmitted to the body. Deficits in fine or gross motor skills movements interfere with activities of daily living. It is often described as disorder in skill acquisition, where the learning and execution of coordinated motor skills is substantially below that expected given the individual's chronological age. Difficulties may present as clumsiness, slowness and inaccuracy of performance of motor skills. It is often accompanied by difficulty with organisation and/or problems with attention, working memory and time management.

The KE family is a medical name designated for a British family, about half of whom exhibit a severe speech disorder called developmental verbal dyspraxia. It is the first family with speech disorder to be investigated using genetic analyses, by which the speech impairment is discovered to be due to genetic mutation, and from which the gene FOXP2, often dubbed the "language gene", was discovered. Their condition is also the first human speech and language disorder known to exhibit strict Mendelian inheritance.

In human development, muteness or mutism is defined as an absence of speech, with or without an ability to hear the speech of others. Mutism is typically understood as a person's inability to speak, and commonly observed by their family members, caregivers, teachers, doctors or speech and language pathologists. It may not be a permanent condition, as muteness can be caused or manifest due to several different phenomena, such as physiological injury, illness, medical side effects, psychological trauma, developmental disorders, or neurological disorders. A specific physical disability or communication disorder can be more easily diagnosed. Loss of previously normal speech (aphasia) can be due to accidents, disease, or surgical complication; it is rarely for psychological reasons.

A speech sound disorder (SSD) is a speech disorder affecting the ability to pronounce speech sounds, which includes speech articulation disorders and phonemic disorders, the latter referring to some sounds (phonemes) not being produced or used correctly. The term "protracted phonological development" is sometimes preferred when describing children's speech, to emphasize the continuing development while acknowledging the delay.

Apraxia of speech (AOS), also called verbal apraxia, is a speech sound disorder affecting an individual's ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability. By the definition of apraxia, AOS affects volitional movement pattern. However, AOS usually also affects automatic speech.

Language-based learning disabilities or LBLD are "heterogeneous" neurological differences that can affect skills such as listening, reasoning, speaking, reading, writing, and math calculations. It is also associated with movement, coordination, and direct attention. LBLD is not usually identified until the child reaches school age. Most people with this disability find it hard to communicate, to express ideas efficiently and what they say may be ambiguous and hard to understand It is a neurological difference. It is often hereditary, and is frequently associated to specific language problems.

Speech and language impairment are basic categories that might be drawn in issues of communication involve hearing, speech, language, and fluency.

Motor speech disorders are a class of speech disorders that disturb the body's natural ability to speak due to neurologic impairments. These neurologic impairments make it difficult for individuals with motor speech disorders to plan, program, control, coordinate, and execute speech productions. Disturbances to the individual's natural ability to speak vary in their etiology based on the integrity and integration of cognitive, neuromuscular, and musculoskeletal activities. Speaking is an act dependent on thought and timed execution of airflow and oral motor / oral placement of the lips, tongue, and jaw that can be disrupted by weakness in oral musculature (dysarthria) or an inability to execute the motor movements needed for specific speech sound production. Such deficits can be related to pathology of the nervous system that affect the timing of respiration, phonation, prosody, and articulation in isolation or in conjunction.

Speech acquisition focuses on the development of vocal, acoustic and oral language by a child. This includes motor planning and execution, pronunciation, phonological and articulation patterns.

<span class="mw-page-title-main">Simon Fisher</span> British geneticist and neuroscientist (born 1970)

Simon E. Fisher is a British geneticist and neuroscientist who has pioneered research into the genetic basis of human speech and language. He is a director of the Max Planck Institute for Psycholinguistics and Professor of language and genetics at the Donders Institute for Brain, Cognition and Behaviour in Nijmegen, The Netherlands.

Developmental Language Disorder (DLD) is identified when a child has problems with language development that continue into school age and beyond. The language problems have a significant impact on everyday social interactions or educational progress, and occur in the absence of autism spectrum disorder, intellectual disability or a known biomedical condition. The most obvious problems are difficulties in using words and sentences to express meanings, but for many children, understanding of language is also a challenge. This may not be evident unless the child is given a formal assessment.

Kathryn Emma Watkins is an experimental psychologist in the Wellcome Trust centre for integrative neuroimaging at the University of Oxford and a tutorial fellow at St Anne's College, Oxford. Her research investigates the brain processes that underlie speech, language and development.

References

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  17. ↑ Raca G, Baas BS, Kirmani S, Laffin JJ, Jackson CA, Strand EA, Jakielski KJ, Shriberg LD (April 2013). "Childhood Apraxia of Speech (CAS) in two patients with 16p11.2 microdeletion syndrome". European Journal of Human Genetics. 21 (4): 455–9. doi:10.1038/ejhg.2012.165. PMC   3598318 . PMID   22909774.
  18. ↑ Worthey EA, Raca G, Laffin JJ, Wilk BM, Harris JM, Jakielski KJ, Dimmock DP, Strand EA, Shriberg LD (October 2013). "Whole-exome sequencing supports genetic heterogeneity in childhood apraxia of speech". Journal of Neurodevelopmental Disorders. 5 (1): 29. doi: 10.1186/1866-1955-5-29 . PMC   3851280 . PMID   24083349.
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  20. ↑ Shriberg LD, Potter NL, Strand EA (April 2011). "Prevalence and phenotype of childhood apraxia of speech in youth with galactosemia". Journal of Speech, Language, and Hearing Research. 54 (2): 487–519. doi:10.1044/1092-4388(2010/10-0068). PMC   3070858 . PMID   20966389.
  21. ↑ Shriberg LD, Ballard KJ, Tomblin JB, Duffy JR, Odell KH, Williams CA (June 2006). "Speech, prosody, and voice characteristics of a mother and daughter with a 7;13 translocation affecting FOXP2". Journal of Speech, Language, and Hearing Research. 49 (3): 500–25. doi:10.1044/1092-4388(2006/038). PMID   16787893.
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  23. 1 2 Newmeyer AJ, Grether S, Grasha C, White J, Akers R, Aylward C, Ishikawa K, Degrauw T (September 2007). "Fine motor function and oral-motor imitation skills in preschool-age children with speech-sound disorders". Clinical Pediatrics. 46 (7): 604–11. doi:10.1177/0009922807299545. PMID   17522288. S2CID   43885254.
  24. ↑ Grigos MI, Kolenda N (January 2010). "The relationship between articulatory control and improved phonemic accuracy in childhood apraxia of speech: a longitudinal case study". Clinical Linguistics & Phonetics. 24 (1): 17–40. doi:10.3109/02699200903329793. PMC   2891028 . PMID   20030551.
  25. ↑ Newmeyer AJ, Aylward C, Akers R, Ishikawa K, Grether S, deGrauw T, Grasha C, White J (2009). "Results of the Sensory Profile in children with suspected childhood apraxia of speech". Physical & Occupational Therapy in Pediatrics. 29 (2): 203–18. doi:10.1080/01942630902805202. PMID   19401932. S2CID   45413362.
  26. 1 2 McNeill BC, Gillon GT, Dodd B (2009). "Effectiveness of an integrated phonological awareness approach for children with childhood apraxia of speech (CAS)" (PDF). Child Language Teaching and Therapy. 25 (3): 341–366. doi:10.1177/0265659009339823. hdl: 10092/2375 . S2CID   39652370.
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