Apraxia of speech: Difference between revisions
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==Developmental Apraxia of Speech== |
==Developmental Apraxia of Speech== |
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Developmental Apraxia of Speech (also called Childhood AOS or DAS) is the least common form of AOS, only constituting 15% of all reported cases, but is the most difficult to treat. Those with DAS are born with the disorder. The cause of this form of AOS is not certain, but a correlation between DAS and Fetal Alcohol Syndrome (FAS) has been discovered. Most cases of DAS are reported between the ages of 3 and 5. In most cases of DAS, like other forms of AOS, an impaired neural connection between the brain and the muscles of the tongue is discovered. Those with DAS cannot tell they talk differently or with an accent because there is nothing wrong with the memories in the brain; this creates a large amount of frustration for those with DAS when they are able to express their ideas entirely or at all in the severe cases. This makes them prone to violence in pre-school and early grade school when they are unable to express themselves in any other format. Few people with DAS ever advance beyond a 7-year-old's level of linguistics, even after years of speech therapy. |
Developmental Apraxia of Speech (also called Childhood AOS or DAS) is the least common form of AOS, only constituting 15% of all reported cases, but is the most difficult to treat. Those with DAS are born with the disorder. The cause of this form of AOS is not certain, but a correlation between DAS and Fetal Alcohol Syndrome (FAS) has been discovered. Most cases of DAS are reported between the ages of 3 and 5. In most cases of DAS, like other forms of AOS, an impaired neural connection between the brain and the muscles of the tongue is discovered. Those with DAS cannot tell they talk differently or with an accent because there is nothing wrong with the memories in the brain; this creates a large amount of frustration for those with DAS when they are able to express their ideas entirely or at all in the severe cases. This makes them prone to violence in pre-school and early grade school when they are unable to express themselves in any other format. Few people with DAS ever advance beyond a 7-year-old's level of linguistics, even after years of speech therapy.{{fact}} |
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==Stroke-associated== |
==Stroke-associated== |
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Revision as of 16:10, 31 March 2011
Apraxia of Speech (AOS) is a motor speech disorder affecting an individual's ability to translate conscious speech plans into motor plans. Like other apraxias, it only affects volitional movement patterns. Dyspraxia of speech, verbal dyspraxia, and other terms, usually refer to variants of AOS, or a less severe version of the disorder. Apraxia of Speech can be divided into three general categories: developmental, stroke-associated, and stress-induced.[1]
Developmental Apraxia of Speech
Developmental Apraxia of Speech (also called Childhood AOS or DAS) is the least common form of AOS, only constituting 15% of all reported cases, but is the most difficult to treat. Those with DAS are born with the disorder. The cause of this form of AOS is not certain, but a correlation between DAS and Fetal Alcohol Syndrome (FAS) has been discovered. Most cases of DAS are reported between the ages of 3 and 5. In most cases of DAS, like other forms of AOS, an impaired neural connection between the brain and the muscles of the tongue is discovered. Those with DAS cannot tell they talk differently or with an accent because there is nothing wrong with the memories in the brain; this creates a large amount of frustration for those with DAS when they are able to express their ideas entirely or at all in the severe cases. This makes them prone to violence in pre-school and early grade school when they are unable to express themselves in any other format. Few people with DAS ever advance beyond a 7-year-old's level of linguistics, even after years of speech therapy.[citation needed]
Stroke-associated
Stroke-associated AOS is the most common form of AOS with about 60% of all AOS cases reported. This is one of the several possible disorders that can result from a stroke, but only about 11% of stroke cases involve this disorder. Brain damage to the neural connections, and especially the neural synapses, during the stroke leads to this disorder. Most cases of Stroke-associated AOS are minor, but in the most severe cases, all linguistic motor function can be lost and must be relearned. Since most with this form of AOS are at least fifty years old, few fully recover to their previous state of linguistics.[2]
Stress-induced
Stress-induced AOS account for about 25% of all cases of AOS in the United States and Canada. This is the least severe of the forms and often last only a few weeks. It is marked by an inability to communicate effectively after overwhelming levels of unresolved stress. The three major sources of stress that induce this form of AOS are long drawn-out divorces, high-profile criminal cases, and incidences of extreme child abuse.[3]
Nature and Symptoms
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.
Symptoms are evident only in connected speech.
Causes
AOS is often associated with Broca's Aphasia. It is actually characterised by damage to the posterior portion of Broca's area; the insula, an area underneath the inferior-anterior portion of the temporal lobe, concealed by the fissure separating the frontal and temporal lobes; and the lentiform nucleus (Dronkers, 1996). However, some studies have shown that only a percentage of patients with AOS have these lesions (Hillis, 2004).
Differential Diagnosis
AOS, in adults (where it is an acquired condition), can often be diagnosed as conduction aphasia. Key difference between AOS and other disorders are:
- Repetitive production of a single word (e.g. re-fridg-er-rat-or) will tend to become progressively more intelligible in conduction aphasia sufferers, but AOS speakers will consistently produce the same errors, and repetitions will not improve
- Errors produced in a task by an AOS sufferer are consistent across type (e.g. voice phoneme unvoiced, fronted consonant backed), where other illnesses produce inconsistent errors on repetition of a task
- SMR (sequential motor rate, e.g. 'pataka pataka') rates are slower than AMR (alternating motor rate, e.g. 'papapa' or 'kakaka') rates for AOS sufferers
- Oromotor tasks will not yield AOS symptoms, only tasks requiring production of connected speech
Not present in AOS, and ruling out its diagnosis are features such as:
- Anticipatory errors - such as a final consonant altering initial consonant e.g. 'dunited states'
- Transposition errors - e.g. 'park'->'carp'
- Weakness of oral structures (oromotor weakness is not the result of AOS, though it may be co-occurring if there is also a dysarthria present)
Features definitively excluding AOS are:
- Fast/normal speech rate
- Normal stress patterns, and smooth transition between words and syllables
Resources
- ^ Hall, P. & Jordan, L. & Robin, D. (2010.) Developmental Apraxia of Speech: Theory and Clinical Practice. Pro-Ed. New York, New York. October 31, 2006.
- ^ Hall, P. & Jordan, L. & Robin, D. (2010.) Developmental Apraxia of Speech: Theory and Clinical Practice. Pro-Ed. New York, New York. October 31, 2006.
- ^ Hall, P. & Jordan, L. & Robin, D. (2010.) Developmental Apraxia of Speech: Theory and Clinical Practice. Pro-Ed. New York, New York. October 31, 2006.