Understanding Apraxia

Understanding Apraxia Defining and understanding Apraxia: terminology, types, prevalence, and causes.

What is Apraxia?

Apraxia is a neurogenic impairment involving planning, executing, and sequencing motor movements.  The National Institute of Health defines apraxia as a disorder of the nervous system. 

Apraxia is perhaps the most misunderstood of all the speech disorders. Verbal apraxia is a neurological motor speech impairment that involves a breakdown in the transmission of messages from the brain to the muscles in the jaw, cheeks, lips, tongue and palate that facilitate speech. There is no obvious weakness in these muscles and a child may well be able to move them quite happily when not trying to speak. Apraxic children, who are usually seen as "just late talkers" when young, are able to comprehend language at an age appropriate level, however have difficulty expressing themselves using speech. With apraxia, a child knows what he or she wants to say but there is a road block obstructing the signal from the brain to the mouth. For any child with a speech disorder, but especially with apraxia, the earlier therapy is begun, the better the results for your child and his or her social-emotional development.

Praxis
Medieval Latin, from Greek, from prassein
Definition: doing, action, to do, practice
Source: Merriam-Webster Dictionary

 

Different Types of Apraxia

Verbal apraxia (VA) is a motor speech disorder that interferes with an individuals’ ability to correctly pronounce sounds, syllables, and words.  It is a neurologically-based motor planning disorder of unknown cause.  It affects the programming of the articulators and rapid sequences of muscle movements for speech sounds. Verbal apraxia may occur as part of many neurological conditions or may occur in isolation.

Other names: Developmental Dyspraxia, Developmental Apraxia, Childhood Apraxia of Speech, Developmental Apraxia of Speech, Speech Apraxia, Speech Dyspraxia

Motor apraxia involves the programming of hand, leg, or whole body movement.  Motor apraxia often occurs with verbal apraxia (but not all children with motor apraxia have verbal apraxia.)

Other names: Developmental Coordination Disorder, Clumsy Child Syndrome, Global Dyspraxia, Limb Apraxia, Dyspraxia, or Developmental Dyspraxia

Other types of apraxia: Ideational or Ideomotor.  Both are related to the inability to perform a learned task (e.g. putting on socks before shoes or combing hair with a toothbrush).

 

Apraxia v. Dyspraxia

Frequently interchanged and synonymous:

Root:
Praxis – ability to plan movement

Prefixes:
“a” – medical terminology usually means the absence of something, without  (total) apraxia is without the ability to execute movement
“dys” – medical terminology means partial ability or partial loss, inability or lack of function (partial absence or lack of function)

dyspraxia is the impairment of the ability execute movement

In children with apraxia, the difference would be that an apraxic child would be unintelligible while a dyspraxic child would have some intelligibility.

Global apraxia – praxis is in entire body

 

Prevalence & Causes

Prevalance

Apraxia occurs 8 times more often in boys than in girls.  Due to incorrect diagnosis or lack of diagnosis, the actual number of children with apraxia is hard to determine, but there appears to be a 30-fold increase in the last 20 years.

About half of children with an Autism Spectrum Disorder (ASD) have verbal or oral apraxia, although not all children with verbal apraxia have ASD.  Experts believe the number of children with autism exceeds 500,000 in the US alone, and 50% of autistic children may have Apraxia. 

Causes of Apraxia

Although the specific causes are unknown,  possibilities include:

  • Result of direct neurological damage
  • As a complex neurobehavioral disorder (genetic, metabolic)
  • A neurogenic speech sound disorder (speech delay, verbal apraxia)

 

Apraxia of Speech Glossary

Definitions for apraxia-related terms and for similar speech and language disorders.

Aphasia – A loss of the ability to produce and/or comprehend language, due to injury to brain areas specialized for these functions.

Apraxia – A neurological disorder characterized by loss of the ability to execute or carry out learned purposeful movements, despite having the desire and the physical ability to perform the movements.

Apraxia of Speech (AOS) – A motor speech disorder (MSD) affecting an individual’s ability to translate conscious speech plans into motor plans. Like other apraxias, it only affects volitional movement patterns. Sufferers of AOS have impaired prosody, which causes their speech to be slow, highly segmented (at the syllable or word level), and is often described as ‘robotic’. Because of this, they also exhibit equal syllabic stress (tec-ton-ic as opposed to tec-TON-ic), and have trouble consciously producing correct stress patterns, even though they are aware of prosodic patterns required.

Autism – A brain development disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior.

Broca’s Aphasia (Expressive Aphasia) – Sufferers of this form of aphasia exhibit lack of grammar and syntax in speech. For them, speech is difficult to initiate, non-fluent, labored, and halting. Similarly, writing is difficult as well. Intonation and stress patterns are deficient. Language is reduced to disjointed words and sentence construction is poor, omitting function words and inflections

Developmental Milestones – Tasks most children learn, or physical developments, that commonly appear in certain age ranges.  “Developmental delay”  is used to describe the condition where a child does not reach one of these stages at the expected age.

Dyslexia – A learning disability that manifests primarily as a difficulty with written language, particularly with reading and spelling.

Dyspraxia – Developmental dyspraxia is one or all of a heterogeneous range of development disorders affecting the initiation, organization and performance of action.  Patients may have partial loss of the ability to coordinate and perform certain purposeful movements and gestures, in the absence of other motor or sensory impairments.

Dyspraxia of Speech – A less severe version of the apraxia of speech.

Early Childhood Intervention – A support system for children with developmental disabilities or delays and their families.  If a child experiences a developmental delay, this can compound over time. The principle of early intervention is to provide appropriate therapies for children with disabilities, to minimize these delays and maximize their chances of reaching normal milestones in development.

Manner of Articulation – Also called “speech production,” describes how the tongue, lips, jaw, and other speech organs are involved in making a sound.

Motor Cortex – Regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions, such as the mouth movements used to create speech. 

Motor Speech Disorders – A group of speech disorders resulting from disturbances in muscular control-weakness, slowness, or incoordination- of the speech mechanism due to damage to the central or peripheral nervous system or both. The term encompasses coexisting neurogenic disorders of several or all the basic processes of speech: respiration, phonation, resonance, articulation, and prosody

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Speech Pathology or Therapy – The study of disorders that affect a person’s speech, language, cognition, voice, or swallowing, and the rehabilitative or corrective treatment of physical and/or cognitive disorders resulting in difficulty with communication and/or swallowing
Verbal apraxia – Alternative name for apraxia of speech.

Wernicke’s Aphasia (Receptive Aphasia) – Speech is preserved, but language content is incorrect. This may vary from the insertion of a few incorrect or nonexistent words to a profuse outpouring of jargon. Grammar, syntax, rate, intonation and stress are normal. Substitutions of one word for another ( e.g. “telephone” for “television”) are common. Comprehension and repetition are poor.