Apraxia and Related Syndromes

Updated: Sep 25, 2017
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Overview

Overview

Apraxia, one of the most important and least understood major behavioral neurology syndromes, robs patients of the ability to use tools. Therefore, patients with apraxia are unlikely to perform activities of daily living well.

Apraxia of speech is now recognized as an articulation disorder distinct from dysarthria and aphasia. [1]

Apraxia has a neurologic cause that localizes fairly well to the left inferior parietal lobule, the frontal lobes (especially the premotor cortex, supplementary motor area, and convexity), or the corpus callosum. Any disease of these areas can cause apraxia, although stroke and dementia are the most common causes. Interestingly, callosal apraxia is rare after callosotomy and is much more common with anterior cerebral artery strokes or tumors.

Heilman defined apraxia in negative terms, characterizing it 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." [2] 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.

Apraxia is one of the best localizing signs of the mental status examination and, unlike aphasia, also predicts disability in patients with stroke or dementia. Patients who have aphasia but who do not have coexisting apraxia can live independently, take the bus or subway, and lead a relatively normal life, while a patient with significant limb apraxia is likely to remain dependent.

No good data exist concerning the occurrence of apraxia in different age groups. However, it is more common in older age groups, as they typically have higher frequencies of stroke and dementia.

Complications

Patients with useless limbs syndrome can progress to a clenched, painful fist, while persons with certain progressive diseases, such as progressive supranuclear palsy, corticobasal ganglionic degeneration, and stroke, may be at high risk of falling, and patients with dementias may develop secondary nutritional deficiencies.

Prognosis

In general, patients with apraxia become dependent for their activities of daily living and require at least some degree of supervision; skilled nursing care may be required. Patients with degenerative diseases or tumors usually progress to increased levels of dependence.

Patients with stroke may have a stable course and may even improve somewhat. Persistence of apraxia of speech after 12 months is associated with larger volume of the left-hemispheric stroke involving the Broca area. [3] .

Patient education

Education of the patient's family is obviously a key part of evaluation. For patient education information, see the Brain and Nervous System Center, as well as Stroke and Stroke-Related Dementia.

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Types of Apraxia

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

  • Body part affected (eg, limb apraxia or buccofacial apraxia) [4]
  • Dysfunctional sensory area (left inferior parietal) or motor areas (left premotor and left supplementary motor)
  • If use of tools is affected (transitive vs intransitive)
  • Deficits in pantomiming tool use and gesture (ideomotor apraxia)
  • If knowledge about the use of tools is preserved (conceptual apraxia)

Conceptual apraxia is defined as a loss of knowledge about tools and the movements associated with their use. Patients with parietal lesions may have this condition. [5] These individuals can be contrasted with patients with supplementary motor area (SMA) lesions or other lesions of the premotor cortex. Patients in the latter group would have normal knowledge about how to move but would be unable to perform the movement correctly because of faulty transcoding of the "innervatory patterns" in the motor cortex.

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Apraxialike Syndromes

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

  • Dressing apraxia - Usually associated with right parietal lesions and part of a neglect syndrome
  • Limb-kinetic apraxia
  • Constructional apraxia - Inability to copy 2-dimensional (2D) drawings or 3D assemblies (may be associated with the right or left parietal and left frontal areas, among other brain regions)
  • Gait apraxia (also called Bruns ataxia) - Part of the triad of symptoms of normal pressure hydrocephalus; no relationship to ideomotor apraxia
  • Gaze apraxia - Part of Balint syndrome; no relationship to ideomotor apraxia
  • Apraxia of eyelid opening - No relationship to ideomotor apraxia
  • Magnetic apraxia
  • Gestural apraxia

Dressing apraxia

Dressing apraxia refers to inattention to the left side when dressing; it signifies a feature of the neglect syndrome rather than the loss of the ability to use tools. Typically, a right hemisphere lesion is implicated. It has no relationship to ideomotor apraxia.

Limb-kinetic apraxia

Limb-kinetic apraxia (as distinct from limb apraxia) means a clumsy hand. Typically, it refers to the inability to make precise movements with the limb, especially the fingers contralateral to a brain injury. For example, patients may not be able to make rapid finger movements, to grasp objects in a pincer fashion, or to perform tapping movements.

Magnetic apraxia

Magnetic apraxia is a type of forced grasp response, which often may be associated with frontal lesions and a degenerative disease known as corticobasal degeneration with neuronal achromasia (Rebeiz syndrome) or with related conditions such as Alzheimer disease and progressive supranuclear palsy. This apraxia may be unilateral (affecting either side) and may resemble utilization behaviors or the alien hand syndrome. Patients may be unable to disengage from objects in front of them.

Gestural apraxia

Gestural apraxia was first described in 1905 by Hugo Karl Liepmann. Unfortunately, the underlying cognitive processes and ways to assess them are still being debated. A vaiety of neuroimaging studies have revealed the involvement of a left-lateralized frontoparietal network, with preferential activation of the superior parietal lobe, intraparietal sulcus and inferior parietal cortex. [6]

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Etiology

Apraxia is a syndrome reflecting motor system dysfunction at the cortical level, exclusive of the primary motor cortex. Normally, in planning movements, previously learned, stored complex representations of skilled movements are used. These 3D, supramodal codes, also called representations or movement formulae, are stored in the inferior parietal lobule of the left hemisphere. Diseases that involve this part of the brain, including strokes, dementias, and tumors, can cause loss of knowledge about how to perform skilled movements.

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 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 tumors or anterior cerebral artery strokes. Although the corpus callosum is not known to be involved directly in the performance of skilled movements, it contains fibers crossing from the right hemisphere to the premotor cortex. This type of apraxia represents a classic disconnection syndrome; patients with callosal apraxia typically are apractic only with the left hand.

Cognitive and behavioral impairments are considered to occur frequently in amyotrophic lateral sclerosis/motor neuron disease (MND). Rarely, apraxia has been reported in MND. Based on tractography findings, Lobo et al recently described the first report of an asymmetric presentation of an apraxic syndrome in MND-frontotemporal dementia. [7]

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Patient History

Frequently, patients with apraxia are unaware of their deficits. Accordingly, a history of a patient's ability to perform skilled movements should be obtained from the patient and his or her caregivers.

Caregivers should be asked about the ability of patients to perform activities of daily living, especially those that involve household tools (eg, using a knife, fork, and toothbrush correctly; using kitchen utensils safely and correctly to prepare a meal; using tools such as a hammer or scissors correctly).

Caregivers should also be queried about the overall activity level of the patient and whether reductions in his or her total activities have occurred. The patient may simply sit on the couch and watch television, uninterested in previously important activities. This apathy can be associated with many different kinds of brain dysfunction, but it occasionally occurs because the patient is unable to perform his or her usual activities.

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Physical Examination

Ideomotor apraxia

Testing for ideomotor apraxia can be performed at the bedside with simple tests for the ability to use tools. The examiner asks patients to perform 3 pantomimes of activities. The author of this article asks patients to pantomime hammering a nail into the (imaginary) wall in front of them, screwing a screw into the wall, and using a pair of scissors to cut a piece of paper. [8]

Many other pantomimes could be performed, however, including brushing teeth, cutting with a saw, whipping eggs with an eggbeater, or peeling a potato.

A healthy response to any of these commands is to perform a crisp, well-planned movement. Patients should perform the movement with the hand oriented correctly to hold an imaginary tool, with the tool held at the correct orientation and distance from the target (eg, a wall, screw, or piece of paper), and with the motion performed in such a way that the action is achieved. In other words, the author would like to see an action that would successfully cut a piece of paper, as if scissors and paper were really there.

Any type of error in performing the above activities (in the absence of aphasia or lack of comprehension of the command or in the absence of motor deficit) implies a loss of knowledge about the movement to be performed. If the hand is not oriented to hold the tool correctly, if the action is performed in the wrong plane, if the target (eg, wall) is not located correctly, or if movement is performed incorrectly, the response is scored as an error.

Buccofacial apraxia

Buccofacial apraxia implies a completely different process and lesion; it is tested separately. Unlike limb apraxia, in which a patient cannot perform skilled movements with the limbs, in buccofacial apraxia (also called oral apraxia), patients cannot perform skilled actions involving the lips, mouth, and tongue, despite the absence of paresis. Localization also is unique.

In buccofacial apraxia, the lesion is usually in or near area 44 (ie, the Broca area). To test for buccofacial apraxia, the patient should be asked to perform tasks with his or her mouth, such as blowing out a match, kissing, or brushing his or her teeth.

Constructional apraxia

Constructional apraxia refers to the inability to draw or copy quality pictures, such as interlocking pentagons, or complex figures, such as the Rey-Osterreith figure. Constructional apraxia can localize damage to several brain regions, including the frontal or left or right parietal area.

Patients with frontal damage tend to perseverate on or repeat elements of the figure or to transform elements into familiar elements, such as transforming the circle with 3 dots into a face. Patients with right hemisphere damage (especially parietal) on the whole do worse than patients with left hemisphere damage at integrating the basic elements of the diagram, although left hemisphere ̶ damaged patients can also make many errors. [9]

Corticobasal degeneration

Unilateral apraxia may be the presenting sign of corticobasal degeneration; memory is typically unaffected early. (Rarely, Alzheimer disease, progressive supranuclear palsy, Pick disease, and nonspecific degenerative dementia can present with that phenotype.) In addition to apraxia, patients may develop a truly useless limb and bizarre behaviors with the limb, including magnetic responses, forced grasping, and levitation of the limb. These clinical features are common, but they are not absolutely necessary for the diagnosis. The pathology described in this condition, balloon cells with neuronal achromasia, is unique.

Other diagnostic considerations

The nature of the patient’s response is important. Additional tests for apraxia can include the ability to imitate commands (in aphasic patients), the ability to select by choice correct and incorrect movements, and the ability to perform commands with each hand. Patients may be asked to use a tool or to perform an act when viewing a tool.

In a report, Goldenberg hypothesized that “imitation of meaningless gestures and use of tool and objects depend on left parietal lobe integrity because of their demands on categorical apprehension of spatial relationships between multiple objects or between multiple parts of objects.” [10]

Sometimes, testing the patient in a more practical setting may be necessary. For example, a patient may perform well by imitating movements without the use of tools. However, if a dinner tray with a fork, a pencil, and a toothbrush is presented, selection of the wrong tool may be more obvious and evident.

Rothi has described a number of apraxia error types. These include errors of orientation of the hand around the object, errors of external spatial orientation, and movement errors. Other error types include perseverative errors (ie, repeating a previously made movement), body-part-as-tool errors (ie, using the hand as the hammer rather than holding a hammer), and body-part-as-object errors (ie, hand as the object of the action). While these errors can confirm that apraxia is present, no correlation can be made between lesion site and error type.

In a recent study by Whitwell et al, differences between primary progressive apraxia of speech and progressive supranuclear palsy were compared. All progressive supranuclear palsy subjects had typical oculomotor/gait impairments, but none had speech apraxia. Both syndromes showed gray matter loss in supplementary motor areaa, white matter loss in posterior frontal lobes, and degeneration of the body of the corpus callosum. While lateral gray matter loss was focal, involving superior premotor cortex, in primary progressive apraxia of speech, loss was less focal and extended into the prefrontal cortex in progressive supranuclear palsy. [11]

Comorbidities

When evaluating patients with apraxia, neighborhood signs also should be checked. For example, buccofacial apraxia usually occurs with Broca aphasia, whereas limb apraxia due to a parietal lesion may co-occur with Wernicke aphasia if the temporal lobe also is involved, or conduction aphasia or features of Gerstmann syndrome (ie, acalculia, right-left confusion, alexia with agraphia) if the angular gyrus also is involved.

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Differential Diagnosis

The differential diagnosis for ideomotor apraxia includes the following:

  • Hemiparesis
  • Movement disorders such as Parkinson disease and dystonia [12]
  • Deafferentation
  • Hysteria
  • Malingering

The differential diagnosis for corticobasal ganglionic degeneration includes the following:

  • Alzheimer disease
  • Progressive supranuclear palsy
  • Pick disease
  • Other frontotemporal dementias
  • Nonspecific progressive gliosis

The differential diagnosis for the cause of ideomotor apraxia includes the following:

  • Stroke
  • Dementia
  • Other mass lesions
  • Central nervous system (CNS) infection and inflammation
  • Multiple sclerosis
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Workup

Imaging studies

A patient with suspected apraxia should undergo neuroimaging—either computed tomography (CT) scanning or magnetic resonance imaging (MRI)—to exclude a mass lesion and to evaluate for possible atrophy suggestive of a degenerative condition.

In a study by Whitwell et al aimed to determine the neuroanatomical and metabolic correlates of progressive apraxia of speech (AOS) and aphasia, correlations between the Western Aphasia Battery and Token Test to assess Aphasia, an AOS rating scale (ASRS), 3-Tesla MRI, and 18-F fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging were assessed. The only region that correlated to ASRS was left-superior promotor volume. [13]

Histologic findings

The histologic findings in apraxia depend on whether the underlying cause is stroke, degenerative disease, or tumor. Specific histologic findings most often can be found in degenerative diseases. In Alzheimer disease, for example, amyloid plaques and neuritic tangles are found. In Pick disease, Pick bodies are seen. In corticobasal ganglionic degeneration, balloon neurons with neuronal achromasia are characteristic.

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Rehabilitation

Physical and occupational therapy are important as part of the patient’s assessment and treatment. However, patients may not request such therapy, because they may be unaware of their deficits.

Occupational therapy, if appropriate, must be considered to assist the patient in using the affected limb and in attaining maximum independence. [4]

Physical therapy is appropriate for patients with diseases that are considered high risk for falls. Such therapy is useful not only to provide the patient with training or exercises designed to increase his or her safety but also to modify the individual’s environment, to provide assistive devices, and to teach the caregivers. Therefore, therapy may be beneficial even for patients who are demented and incapable of a great amount of new learning.

Patients with childhood apraxia of speech (CAS) are at risk for persistent reading and spelling disorder in addition to their spoken communication difficulties. [14] A potential benefit has been shown in an integrated approach involving the simultaneous improvement of speech, phonologic awareness, and decoding ability. However, a Cochrane database review by Morgan and Vogel demonstrated a significant lack of well-controlled treatment studies addressing the efficacy of therapies for CAS. [15, 16]

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Pharmacologic Therapy

Medicines are not known to be effective for the treatment of ideomotor apraxia.

Carbidopa-levodopa (Sinemet) and dopamine agonist medications (eg, ropinirole [Requip], pramipexole [Mirapex]), typically are not effective for corticobasal ganglionic degeneration, although they are tried frequently.

Antispasticity treatments, such as baclofen (Lioresal), tizanidine (Zanaflex), and botulinum toxin (Myobloc), can be tried for patients with a clenched fist due to a useless limb. Cholinesterase inhibitors, such as donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne), and memantine (Namenda), may be used for progressive dementia syndromes, especially Alzheimer disease.

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Diet and Activity

Patients with apraxia may have difficulty knowing how or what to eat. If a patient is losing weight or nutritional deficiencies are suspected, nutritional supplements or dietary assistance may be provided. Patients with certain types of dementia may have a high risk of falling. Patients with corticobasal ganglionic degeneration or progressive supranuclear palsy may have a high fall rate relatively early in the disease, whereas patients with Alzheimer are more likely to fall in the middle to late stages. Patients with a useless upper limb may develop a clenched, painful fist that severely limits activity.

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Prognosis

In general, patients with apraxia become dependent for their activities of daily living and require at least some degree of supervision; skilled nursing care may be required. Patients with degenerative diseases or tumors usually progress to increased levels of dependence.

Patients with stroke may have a stable course and may even improve somewhat. Persistence of apraxia of speech after 12 months is associated with larger volume of the left hemispheric stroke involving Broca's area.

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