Apraxia in Dementia: Jumbled Movements

Apraxia can be further classified into 3 subtypes:

1. Ideomotor
2. Ideational
3. Limb-kinetic apraxia.

Dementia and Apraxia

Apraxia is found in a variety of neurological disorders including dementia.

Apraxia has been shown to negatively affect quality of life. Therefore, recognition and treatment of this disorder is critical. This article provides an overview of apraxia and highlights studies dealing with the use of motor training and noninvasive brain stimulation as treatment.

Skills and Learned Movements

A typical daily life involves carrying out a variety of movements. Movements can be divided into those requiring use of tools and those that do not.¹ 

Food preparation and housework are examples of the former, often requiring the use of kitchen tools and home appliances. Dressing, cleansing and grooming require multi-step sequential actions and at times, fine movements of the upper limb. Needless to say, the ability to perform such actions essential to daily living is integral to one’s functional independence.

Praxis is defined as the ability to perform such skilled or learned movements. Apraxia refers to the inability to carry out such praxis movements in the absence of elementary motor, sensory or coordination deficits that could serve as the primary cause.

Knowledge on the subject of apraxia has expanded. New insights very likely open up possibilities for the use of neuromodulation as a way to treat this disorder, in conjunction with motor training that has also been attempted as treatment.

History and Classification

Much of the conceptual knowledge of apraxia was established by Hugo Liepmann, a pioneer in the field of cognitive neurology who described this phenomenon in a stroke patient after studying his manual gestures. Liepmann studied a 48-year-old man who had sustained a left hemispheric stroke and found that he was unable to button a shirt or light a cigar, even after the paresis had largely resolved. However, Liepmann noted that the patient was able to carry out spontaneous movements such using a spoon while eating, perform simple gestures on command, or pantomime. He also made the observation that patients with left hemispheric lesions but not those with right hemispheric lesions were unable to perform praxis movements. (Fig. 1).²

Fig. 1: Reproduction of Liepmann’s schema of the motor engram. Adapted from Roby-Brami et al. Philos Trans R Soc Lond B Biol Sci 2012;367:144-160, with permission of Royal Society Publishing.² 1: limb-kinetic apraxia, 2: ideomotor apraxia, 3: ideational apraxia.

Liepmann further classified apraxia into the following major subtypes; ideomotor, ideational and limb-kinetic apraxia. Apraxias have also been noted⁸ with regard to task-specificity, such as:

• dressing apraxia
• sitting apraxia
• apraxia of eyelid opening
• apraxia of gait

3 Main Types of Apraxia in Dementia

1. Ideomotor apraxia is a subtype of apraxia that is commonly seen in patients with dementia. It is defined as a disorder of gesture performance upon verbal command, despite having intact knowledge of tasks. For example, the patient might be able to describe how to use a spoon, but not able to demonstrate the actual use. This typically results in the patient failing to pantomime a transitive act (“Show me how you would use a screwdriver”).
2. Ideational apraxia, on the other hand, is characterized by inability to conceptualize a task, despite intact identification of the tools. When presented with a stamp and an envelope, one might be able to name the objects, but unable to demonstrate how to mail an envelope using those objects. In this situation, the examiner finds that the patient is unable to correctly sequence a series of actions required in a specific type of activity.
3. Limb-kinetic apraxia is another major subtype of apraxia that indicates the loss of the ability to make precise, independent but coordinated finger and hand movements, resulting in inaccurate or clumsy movements.⁹ Examples of tasks requiring fine motor performance including buttoning or coin rotation, the latter of which has been proposed as a test of motor dexterity.¹⁰

Diagnosing Apraxia

Apraxia is seen in various dementias such as Alzheimer’s, Parkinson’s dementia corticobasal syndrome (CBS) or progressive supranuclear palsy (PSP)].^1,13 In clinical practice, it is not uncommon that more than one type of apraxia is present in a single affected patient.¹⁵

Despite the relatively straightforward recognition of apraxia, several testing methods for apraxia have been developed, but are not quick to use, and therefore not commonly applied in the clinical setting.

• The De Renzi ideomotor apraxia test is a 24-item scale tested in patients with left or right brain damage, developed for the assessment of ideomotor apraxia.¹⁹ 
• More recently, a comprehensive test termed the Test of Upper Limb Apraxia (TULIA) was developed, which includes non-symbolic (meaningless), intransitive (communicative) and transitive (tool-related) gestures.²⁰ This 48-item test was found to have good reliability and validity, and a more concise, bedside 12-item test based on TULIA was further developed (Apraxia Screen of TULIA; AST), shown to have high specificity and sensitivity (Refer to Appendix 2 of http://jnnp.bmj.com/content/82/4/389.long).

Such bedside tests may allow for a quick and reliable apraxia assessment, which may be clinically applicable and therefore useful for assessing the severity of ideomotor apraxia. These apraxia tests include tasks involving imitation, which can be disturbed in either left or right brain damage. In left brain damage, imitation of hand postures is often disturbed, whereas imitation of finger or foot postures is disturbed in those with right brain damage.¹⁸ There is still a need for tests that test other elements of praxis, such as the actual use of tool and selection of the appropriate task for a given tool, particularly when having more than one to choose from (for example, a knife to cut bread can also be used to stab).

In addition to having the subject perform buttoning or coin-rotation tasks, limb-kinetic apraxia can be assessed by having one perform a pegboard test. This test is sometimes used in neuropsychological testing, and involves lifting one peg at a time, placing it in a hole, and moving on to the next peg, repeating this action.⁸

Treatment: Rehabilitation vs. Noninvasive Brain Stimulation

To date, there is no standardized treatment for apraxia that is available.

In studies, rehabilitative treatment for apraxia was conducted three times weekly, each lasting 50 minutes and conducted over 30 sessions.⁶⁰ Treatment for apraxia consisted of a behavioral training program comprised of gesture-production exercises, made up of three sections dedicated to the treatment of gesture with or without symbolic value and related or nonrelated to the use of objects.⁶¹ Patients who received treatment for apraxia were found to improve in both praxis and activities of daily living (ADL), compared to patients who received conventional treatment for aphasia. Training comprised of 24 communicative gestures was also used in patients with left hemispheric stroke with severe aphasia, resulting in substantial improvement of practiced gestures, and some improvement of unpracticed gestures.⁶² However, based on these reports, the sustainability of such improvement is unclear. Therefore, although rehabilitative training involving practical gestures may be useful in the treatment of patients with apraxia, training alone is likely insufficient for sustained benefit.

Conclusions

Apraxia is a higher-order disorder of sensorimotor integration, commonly seen in dementias such as Alzheimer’s. Praxis requires multiple aspects of cognition and movement to be brought together; to name a few, appreciation of tools as well as the posture of one’s body parts with relation to time and space, sequence of necessary actions, and planning of grasp. As a result, key components of praxis that one should test for include the following: performance using tools, performance in a given situation (such as waving hello), and pantomiming to verbal command and imitation.

Despite its apparent subtleness, apraxia has been noted to cause impairment of daily activities.^9,73 Therefore, while apraxia may not always be immediately evident, it is important to test for as it has been found to have considerable impact on patients’ quality of life.⁷⁴ Advances in neurophysiological techniques allow investigators to probe specific brain areas and obtain more specific information, in contrast to the clinical setting where it is difficult to properly assess the function of each brain area, when multiple regions are lesioned.

Evidence from the aforementioned functional brain imaging studies suggests that praxis requires for appropriate transformation of visual and somatosensory information into movements, such as posture and grasping. Semantic knowledge of objects is also an essential component in praxis. The research indicates that the deficits found in apraxia are likely due to affected networks rather than a specific brain area.

Future exploration of treating apraxia, using different methods of noninvasive brain stimulation are necessary to investigate whether praxis-relevant brain areas can be modulated, and possibly serve as potential targets for treatment. Furthermore, complementing the potential therapeutic effects of noninvasive brain stimulation with rehabilitative training comprised of practical gestures may be a synergistic and useful approach for the treatment of apraxia. Most importantly, with increased recognition of apraxia, proper assessment using available scales, and better ways to treat this disorder, we may be able to lessen the amount of disability these patients suffer from by helping them to ultimately gain functional independence.