Isolated apraxia is relatively uncommon.
Less commonly, apraxia results from damage to other areas of the brain, such as the premotor cortex (the part of the frontal lobe anterior to the motor cortex), other parts of the frontal lobe, or the corpus callosum, or from diffuse damage related to degenerative dementias.
Patients with apraxia cannot conceptualize or do learned complex motor tasks despite having intact motor, sensory, and coordination systems and being able to do the individual component movements. Typically, patients do not recognize their deficits.
Common types of apraxias may include
Ideational apraxia: Patients with ideational apraxia cannot perceive the purpose of a previously learned complex task and thus cannot plan or execute the required voluntary movements in the correct sequence. For example, they may put their shoes on before their socks.
Ideomotor apraxia: This type of apraxia is the most common. When asked to perform common motor tasks, patients with ideomotor apraxia cannot do so. For example, they cannot imitate actions such as waving goodbye or showing how a tool (eg, toothbrush, hammer) is used.
Conceptual apraxia: This type of apraxia is similar to ideomotor ataxia but features an impaired ability to use tools correctly.. For example, when given a screwdriver, patients may try to write with it as if it were a pen.
Constructional apraxia: Patients with constructional apraxia cannot draw, construct, or copy an object even though they understand the task and have the physical ability to do it. For example, patients may be unable to copy a simple geometric shape despite being able to see and recognize it, hold and use a pen, and understand the task.
Bedside tests include asking patients to do or imitate common learned tasks (eg, saluting, stopping or starting to walk, combing hair, striking and blowing out a match, opening a lock with a key, using a screwdriver or scissors, taking a deep breath and holding it). Strength and range of motion must be assessed to exclude motor weakness and musculoskeletal abnormalities as the cause of symptoms.
Neuropsychologic testing or assessment by a physical or occupational therapist may help identify more subtle apraxias. Neuropsychologic testing is standardized testing that provides information about the brain’s structural and functional integrity. It evaluates intelligence, executive function (eg, planning, abstraction, conceptualization), attention, memory, language, perception, sensorimotor functions, motivation, mood and emotion, quality of life, and personality.
Caregivers should be asked about the patient’s ability to do activities of daily living, especially those that involve household tools (eg, correct and safe use of eating utensils, toothbrush, kitchen utensils to prepare a meal, hammer, and scissors) and writing.
Brain imaging (eg, CT, MRI; with or without angiographic protocols) is required to diagnose and characterize central lesions (eg, infarct, hemorrhage, mass, focal atrophy).
There is no specific medical treatment for apraxia. Drugs that slow the symptomatic progression of dementia do not appear beneficial.
Physical and occupational therapy may modestly improve functioning but is more often useful for making the environment safer and for providing devices that help patients circumvent the primary deficit.