Chapter 12: Apraxia

Apraxias are the inability to perform an individual or sequential function in the face of intact motor, sensory and coordinative abilities. A specific motor function is first conceived and is denoted as an engram of movement. This finds a correlate in the cortical negative variant or Bëreitschaft (readiness) potential recorded over the prefrontal and supplementary motor cortices. This then is translated into the required movement. Disorganization of unitary or sequential engrams are the core of apraxia. Different areas of the brain when damaged cause specific apraxias.

Methods of Testing

The examiner must be certain that the patient has no deficits of strength sensation or coordination that would interfere with his or her ability to perform the required tasks. The examiner asks the patient to perform a series of tasks to test specific forms of apraxia. The major apraxias tested are the following:

1. Visual
2. Oral buccal lingual
3. Gait
4. Ideomotor
5. Ideational
6. Constructional
7. Callosal