Apraxia

Apraxia is a disorder caused by damage to specific areas of the cerebrum. Apraxia is characterized by loss of the ability to execute or carry out learned purposeful movements,^[1] despite having the desire and the physical ability to perform the movements. It is a disorder of motor planning, which may be acquired or developmental, but may not be caused by incoordination, sensory loss, or failure to comprehend simple commands (which can be tested by asking the person to recognize the correct movement from a series). Apraxia should not be confused with ataxia, a lack of coordination of movements, aphasia, an inability to produce and/or comprehend language; abulia, the lack of desire to carry out an action; or allochiria, in which patients perceive stimuli to one side of the body as occurring on the other.

There are many different forms of apraxia. Some are listed below:

• Buccofacial or orofacial apraxia. Difficulty carrying out movements of the face on demand. For example, an inability to lick one's lips or whistle.
• Ideational apraxia. Loss of ability to carry out learned complex tasks in the proper order, such as putting on socks before putting on shoes.
• Ideomotor apraxia. Loss of ability to voluntarily perform a learned task when given the necessary objects. For instance, if given a screwdriver, the patient may try to write with it as if it were a pen, or try to comb one's hair with a toothbrush.
• Limb-kinetic apraxia. Difficulty making precise movements with an arm or leg.
• Verbal apraxia. Trouble coordinating mouth movements and speech.^[2]

The root word of apraxia is praxis, Greek for an act, work, or deed. It is preceded by a privative a, meaning without.^[2]

Types

There are several types of apraxia including:

• Buccofacial or orofacial apraxia. nonverbal-oral or buccofacial (inability to carry out facial movements on command; e.g., lick lips, whistle, cough, or wink);
• constructional (inability to draw or construct simple configurations), such as intersecting pentagons;
• gait apraxia
• Ideational apraxia. Loss of ability to carry out learned complex tasks in the proper order, such as putting on socks before putting on shoes.
• limb-kinetic apraxia. Difficulty making precise movements with an arm or leg.
• oculomotor (difficulty moving the eye, especially with saccade movements). This is one of the 3 major components of Balint's syndrome.
• verbal (difficulty planning the movements necessary for speech), also known as Apraxia of Speech (see below);

Each type may be tested at decreasing levels of complexity; if the person tested fails to execute the commands, you can make the movement yourself and ask that the person mimic it, or you can even give them a real object (like a toothbrush) and ask them to use it.

Verbal apraxia of speech

Apraxia may be accompanied by a language disorder called aphasia. Because this is such a frequently encountered type of apraxia, an entire section is devoted to it:

Symptoms of Acquired Apraxia of speech (AOS) and Childhood Apraxia of Speech (CAS) include inconsistent articulatory errors, groping oral movements to locate the correct articulatory position, and increasing errors with increasing word and phrase length. AOS often co-occurs with Oral Apraxia (during both speech and non-speech movements) and Limb Apraxia.

Childhood Apraxia of Speech (CAS) presents in children who have no evidence of difficulty with strength or range of motion of the articulators, but are unable to execute speech movements because of motor planning and coordination problems. This is not to be confused with phonological impairments in children with normal coordination of the articulators during speech.

Acquired apraxia of speech involves the loss of previously acquired speech levels. It occurs in both children and adults who have (prior to the onset of apraxia) acquired some level of speaking ability. Unlike Childhood Apraxia of Speech, AOS is typically the result of a stroke, tumor, or other known neurological illness or injury.

Causes

Ideomotor apraxia is almost always caused by lesions in the language-dominant (usually left) hemisphere of the brain; and, as such, these patients often have concomitant aphasia, especially of the Broca or conduction type. Left-side ideomotor apraxia may be caused by a lesion of the anterior corpus callosum.

Ideational apraxia is commonly associated with confusion states and dementia.

Constructional apraxia is associated with hepatic encephalopathy due to cerebral edema.

Treatment

Recommended treatment for individuals with apraxia includes physical therapy, occupational therapy, play therapy, music therapy, and/or speech therapy.^[3]

Prognosis

The prognosis for individuals with apraxia varies. With therapy, some patients improve significantly, while others may show very little improvement. Some individuals with apraxia may benefit from the use of a communication aid. However, many people with apraxia are no longer able to be independent. They should avoid activities in which they might injure themselves or others.

Occupational therapy and counseling and play therapy may help both patients and their caregivers learn ways to deal with the apraxia. However, because people with apraxia have trouble following instructions, occupational therapy for stroke or other brain injury is difficult.

No drug has been shown useful for treating apraxia.

References

1. ^ "apraxia" at Dorland's Medical Dictionary
2. ^ ^{a b} Heilman KM, Watson RT, Gonzalez-Rothi LJ. Praxis. In: Goetz CG. Goetz: Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2007:chap 4.
3. ^ http://www.ninds.nih.gov/disorders/apraxia/apraxia.htm

• Epstein, O.; Perkin, D.; Cookson, J.; de Bono, D.P. (2003). Clinical Examination. London: Mosby. pp. 294. ISBN 0-7234-3229-5. http://www.fleshandbones.com/bookshop/title.cfm?ISBN=0723432295. 
• Kasper, D.L.; Braunwald, E.; Fauci, A.S.; Hauser, S.L.; Longo, D.L.; Jameson, J.L.. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 2005. ISBN 0-07-139140-1.

External links

• [1]
• Apraxia-Kids
• Apraxia Research
• What is Childhood Apraxia of Speech?
• Apraxia and Other Associated Conditions
• Motor development