Apraxia

What is apraxia?

In the absence of elementary neurological lesions of a motor or sensory nature, we speak of apraxia when the subject manifests an "obvious difficulty or inability" to perform voluntary movements.

More precisely, apraxia is a neuropsychological disorder directly related to movement deficits, both in terms of planning and motor programming: in other words, the apraxic patient is unable to perform precise gestures (movements having meaning) and / or meaningless voluntary movements. It should be pointed out: apraxia does not express precisely a simple uncoordination of the movement, rather a lack of control over the elaboration and planning of voluntary movements.
Most patients with apraxia are unaware of their disorder: we speak of anosognosia, the patient's inability to recognize their neuropsychological deficit.

Meaning of apraxia

The term apraxia comes from the Greek a-praxìa: code number to- indicates a negation, while the suffix –Praxìa it means Do (literally not-doing, impossibility of doing). At the beginning of the 1870s, the doctor Steinthal first coined the term, but inserting it in the wrong context, mainly related to the aphasic syndrome. A century later, another scientist correctly re-evaluated the term, which took on its current meaning: inability to perform and / or control a voluntary movement.

Causes

Apraxia follows from secondary brain pathologies and is never due to dystonia, dyskinesia or ataxia. The most recurrent etiological factor responsible for the disease is certainly attributable to a cerebrovascular lesion: in fact, the most frequent apraxias are mainly due to heart attacks. thrombotic or embolic type, long-term hemodialysis, stroke and brain tumors A close correlation has been observed between Alzheimer's disease and other neurodegenerative diseases in general, and apraxia. In some cases, apraxia can worsen following concomitant psychological illnesses (eg psychogenic motor dysfunction associated with organic pathologies).
Apraxia can be generated by lesions - often partial - of the corpus callosum; in general, the aforementioned lesions cause damage to the left half of the body. Only when the dominant cerebral hemisphere (left, responsible for motor coordination) is affected. , the patient runs the risk of apraxia; brain damage to the non-dominant (right) hemisphere does not cause apraxia.
The apraxia of the corpus callosum involves only the limbs, leaving the facial ones unharmed. [Taken from Movement neurophysiology: anatomy, biomechanics, clinical kinesiology, by M. Marchetti, P. Pilastrini]

Symptoms

The range of motor disorders that can be summarized in apraxia generally affects the muscles of the arms, while those of the legs and face are only hardly affected; apraxia of the trunk is questionable.
The disorders that complete the symptomatic picture of apraxic disorder can be summarized in some main points, shown below in the table:

Clinical aspect of apraxia (design errors)

• Introduction of innovative elements during a gesture
• Lack of some essential elements for the completion of a movement
• Replacing one movement with another incomprehensible
• Bizarre realization of the gesture
• Preservation of movement: the patient continues to repeat that gesture
• Temporal uncoordination: the apraxic subject does not remember the correct sequence of movements aimed at achieving a complete meaningful gesture
• The subject with apraxia uses the hand or fingers as if they were the object (object = hand)

Other articles on "Apraxia"

1. Apraxia: classification
2. Apraxia: diagnosis, therapies and prognosis
3. Apraxia in Brief: A Summary of Apraxia