Equipping People To Make Sense Of What They Are Told
Apraxia - Known as dyspraxia if mild. A neurological disorder characterised by loss
of the ability to execute or carry out skilled movements and gestures, despite having
the desire and the physical ability to perform them. Apraxia results from dysfunction
of the cerebral hemispheres of the brain, especially the parietal lobe, and can arise
from many diseases or damage to the brain.
There are several kinds of apraxia, which may occur alone or together such as:
Buccofacial or orofacial apraxia, which causes the inability to carry out facial
movements on command such as licking lips, whistling, coughing, or winking.
Limb-kinetic apraxia (the inability to make fine, precise movements with an arm or
leg).
Ideomotor apraxia (the inability to make the proper movement in response to a verbal
command).
Ideational apraxia (the inability to coordinate activities with multiple, sequential
movements, such as dressing, eating, and bathing).
Verbal apraxia (difficulty coordinating mouth and speech movements), constructional
apraxia (the inability to copy, draw, or construct simple figures).
Oculomotor apraxia (difficulty moving the eyes on command).
Apraxia may be accompanied by a language disorder called Asphasia.
Corticobasal ganglionic degeneration is a disease that causes a variety of types
of apraxia, especially in elderly adults.
Usually treatment for individuals with apraxia includes physical, speech, or occupational
therapy. If apraxia is a symptom of another disorder, the underlying disorder should
be treated.
Apraxia can occur with lesions in other locations as well. Information contained
in praxis representations is transcoded into innervatory patterns by the premotor
cortices, including the supplementary motor area (SMA) and possibly the convexity
of the premotor cortex; the information is then transmitted to the primary motor
cortex and a movement is performed. Lesions of the SMA or other premotor cortices
also can cause apraxia; in this case, knowledge about movement is still present,
but the ability to perform movement is absent.
Apraxia also occurs with lesions of the corpus callosum, such as tumours or anterior
cerebral artery strokes. Although the corpus callosum is not known to be involved
directly in the performance of skilled movements, it contains crossing fibres from
the right hemisphere to the premotor cortex. This type of apraxia represents a classic
disconnection syndrome; people with callosal apraxia typically are apractic (having
uncoordinated muscular movements, symptomatic of a CNS) disorder only with the left
hand.
The prognosis for individuals with apraxia varies and depends partly on the underlying
cause. Some individuals improve significantly while others may show very little improvement.
