Apraxia and Related Syndromes

Apraxia is one of the most important and least understood major behavioral neurology syndromes. It is one of the best localizing signs of the mental status examination and also predicts disability in patients with stroke or dementia (unlike aphasia). Patients with apraxia cannot use tools; therefore, they are unlikely to perform activities of daily living well. Patients with aphasia, without coexisting apraxia, can live independently, take the bus or subway, and lead a relatively normal life; a patient with significant limb apraxia is likely to remain dependent.

Heilman defined apraxia in negative terms, "Apraxia is defined as a disorder of skilled movement not caused by weakness, akinesia, deafferentation, abnormal tone or posture, movement disorders such as tremors or chorea, intellectual deterioration, poor comprehension, or uncooperativeness."1 To simplify matters, apraxia can be considered a form of a motor agnosia. Patients are not paretic but have lost information about how to perform skilled movements.

There is no consensus on how to divide and organize the many different syndromes known as apraxias. Authors have divided apraxias based on the following:

• Body part affected (eg, limb apraxia or buccofacial apraxia)


• Dysfunctional sensory area (left inferior parietal) or motor areas (left premotor and left supplementary motor)


• If use of tools is affected (transitive vs intransitive)


• If knowledge about the use of tools is preserved (conceptual)


• Deficits in pantomiming tool use and gesture (ideomotor)

The term apraxia is used to describe a variety of syndromes, including the following, which are not considered true apraxias by some.

• Dressing apraxia - Usually associated with right parietal lesions and part of a neglect syndrome


• Constructional apraxia - Inability to copy 2-dimensional drawings or 3-dimensional assemblies (may be associated with right or left


• parietal and left frontal among other brain regions)


• Gait apraxia - Part of the triad of symptoms of normal pressure hydrocephalus


• Gaze apraxia - Part of Balint syndrome


• Apraxia of eyelid opening


• Magnetic apraxia