Apraxia

Apraxia is a diagnosis strongly associated with motor planning .  It primarily affects one’s ability to perform muscle movements.  If you see any type of movement or thought as the result of sequential firing of neurons, then you understand that apraxia is a disorder of neurological sequencing.  Sequencing is a key concept in understanding this.  In order to produce the simplest coherent action, the brain must activate muscles in a certain order.   Without such sequencing, the result is spastic movement; tremors, tics, “loops” and other forms neuromuscular pathology.

Apraxia is not due to problems with the muscles themselves.  It has to do with the messages that the brain sends to the muscles.  In other words, apraxia is a neurological disorder rather than a muscle disorder (see dysarthria).  Apraxia can involve specific types of acts – like speech, but it is more correctly understood in terms of the sequencing of any voluntary movement.  In common usage among specialists who diagnose this disorder (namely, Speech, Occupational, and Physical Therapists, Neuropsychologists, and Neurologists), apraxia refers to the more severe forms, and the term “dyspraxia” refers to milder forms.

Apraxia can be differentiated from autism in that the apraxia can be acquired through brain injury or stroke.  Autism then is associated with a subcategory of this motor sequencing disorder called, “developmental apraxia.”  Actually, there are several diagnoses related to specific sites of apraxia in the body.  Here are a few of the types of apraxias identified so far:

From the National Academy of Neuropsychology

Ideomotor Apraxia

This apraxia is associated with great difficulty in the sequencing and execution of movements. A common test of apraxia is to request the patient to demonstrate the use of a tool or household implement (e.g., “Show me how to cut with scissors”). Difficulties are apparent when the patient moves the hand randomly in space or uses the hand as the object itself, such as using the forefinger and middle finger as blades of the scissors. They have additional trouble sequencing the correct series of movements and make errors in orienting their limbs in space consistent with the desired action. Imitation of the movements of others will usually improve performance but it is still usually defective.

Memories for skilled acts are probably stored in the angular gyrus of the parietal lobe in the left hemisphere. Lesions of this area result in impairment of the execution of motor acts and the patients cannot recognize the correct motor expressions of others. However, the motor execution of skilled acts is mediated by the motor control areas of the frontal lobes. If these areas are lesioned or disconnected from the motor memories in the angular gyrus then the patient also has difficulty expressing the actions but can recognize the correct motor expressions of others. This results in two manifestations of ideomotor apraxia.

Ideational Apraxia

Patients with ideational apraxia cannot perform a series of acts although they may be able to perform the individual components of the series. For example, making coffee requires filling the coffee maker with coffee, adding water then turning on the coffee maker. Patients with ideational apraxia may correctly perform each step but place them out of order, such as turning on the coffee maker first. This disorder results from loss of the conceptual knowledge associated with objects and the overall goal of the activity sequence. Ideational apraxia does not have clear localizing significance and is most often observed among patients with dementia related illnesses.[1]

Buccofacial Apraxia

Patients with this apraxia have difficulty performing skilled movements with the lips, face, tongue, larynx, and pharynx. When asked to blow out a match, suck on a straw or blow a kiss, they appear unable to make the movements or make uncoordinated movements. They may substitute incorrect movements or perseverate. They may also substitute verbal expressions for the movement. For example, when asked to blow out a match, the patient might say “Blow”. Face and mouth motor control areas in the frontal lobes probably mediate these actions. Broca’s aphasia and buccofacial apraxia can exist independently, indicating that control of language expression is independent of simple movement control of the muscles in the vocal apparatus. However, to make matters more confusing, oral apraxia can exist with Wernicke’s aphasia, suggesting that it is more complex than an incoordination of simple motor programs residing in the frontal lobes.

Kinetic Limb Apraxia

Patients who have this form of apraxia cannot make fine motor movements with the limb contralateral to a brain lesion. They have great difficulty performing fine movements, such as picking a coin from a table surface, but will correctly perform gross movements. Lesions of the primary sensory and motor cortex, secondary motor cortex and pyramidal tracts may cause this disorder.

Although individuals with PDDs and ASDs experience apraxias in multiple, gross and fine-motor domains, one of the most readily observable forms of apraxia is verbal apraxia, sometimes called “developmental apraxia of speech” (DAS), or developmental verbal apraxia (DVD).  They are the same thing, and have to do with the sequencing of speech sounds.  Underlying this might be a more basic form called “oral-motor apraxia,” which affects the individual’s ability to coordinate the muscles related to speech (which involves the synchrony of sucking, swallowing and breathing muscles, as well as subordinate processes such as postural support).

There are a few points to keep in mind.  First, apraxia deals mainly with voluntary behavior.  A child may say something, but if asked to do it again, cannot do it.  There is something about the affective information then – the intent or desire to do something, that can fatally complicate the messages the brain sends to the muscles.[2]

The second point has to do with the scope of what praxis (from the Greek meaning an ‘act’ or ‘deed’) is.  The sequencing of perceptions and ideas is incredibly important, and trouble with either of these systems can limit the potential of an individual (severely in the case of ASD) to act spontaneously.  The sequencing of perceptions for example might have to do with knowing what you saw first, and then after that and so on.  A similar type of knowledge can be formed in any sensory input modality.  This is how dynamic tracking works.  The individual observes how actions produce consequences (change; cause and effect) in the environment.  This understanding can involve the linear relationship between a cause and its effect, or it can take into account multiple sources of information, including subjective forms.

Any action or sequence of actions occurs in continuous ongoing feedback loops with perception.  This is how you know how far to reach or how hard you have to swing the hammer.  When walking or riding a bike, your motor and perceptual systems are operating in such a loop – no longer require conscious attention.  Individuals with PDDs and ASDs can have as much difficulty with perceptual distortion as with motor coordination, meaning that the reason for praxis problems may emanate in some or whole part from problems with perception.

And the same is true the other way around: actions influence perceptions.  Orienting towards a stimulus involves motor action.  The iris of the eye opens and closes the lens to control light levels inside the eye, similar to the aperture on a camera.  The saccadic movements of the eyes allow visual tracking. Tiny muscles inside the middle ear control the position of the tiny bones (malleus, incus, and stapes) like tiny satellite dishes orienting to the direction of the signal.  Proprioreceptors and vestibuloreceptors provide ongoing information, so the brain can see something in its correct position, even when one turns her head at an angle (compare this to how a camera works).

Third, as part of the scope of praxis, I include thinking sequentially.  This involves figuring out and executing stepwise actions.  It can be a lot more than simple ideational praxis described above and include the making of long term plans.   For instance, getting a driver’s license involves passing the written and driving tests.  But passing the tests requires learning individual skills, and for each of the skills, there are sequences of steps involved in that learning and so on.

Fourth, figuring out steps and their potential consequences involves recruiting information from multiple sources of memory (perceptual memory [memory of perceptions], procedural memory [memory of muscle actions to the point of automaticity] sequential memory [memory for the order of events], biographical memory [knowledge of other] or autobiographical memory [memory of one’s experience and feelings about things], episodic memory [DS4] [memory of specific scenarios], etc.).  We base what we expect to happen on our past experience – using mental representations from the past and projecting them into the present or future.  For instance, if you were to reach out to pick up your cup for a drink, you would base the amount of force to apply (to manage the weight of the cup) based on your previous experience with that or similar objects.  Too much force might get you splashed in the face and too little might not lift the cup.

And finally, praxis involves the shifting of information in and out of conscious attention and the ongoing search for relevant stimuli.  This is why individuals with ASDs are “captured” by their actions and thoughts, tracking their own movements as if they’re having trouble coordinating them – as we would do in a first dance or ski lesson.

How do we treat Apraxia at SCS?

A very important goal of treatment we have for children is to break the yoke of attention and ongoing motor action.  In other words, children have to learn to track events around them even while they are doing something or thinking about something.  We have methods for getting children to reference information apart from their own actions, the object they have in their hands, the topic they can’t seem to get off of, or the ballistic course of action[DS5]  they may be on, etc.

We also recognize that there are always subordinate perceptual/motor processes underlying what seem like simple skills.  The child who has trouble with postural support will have trouble learning hand/object manipulation, for instance.  Since we use a developmental analysis to get started, and look at how these processes are working, we can bring along skills in the neurologically correct way (and not out of sequence – according to some contrived scale of behaviors to learn).

From National Association of Neurological Disorders and Stroke (NINDS)
www.ninds.nih.gov

What is Apraxia?

Apraxia (called “dyspraxia” if mild) is a neurological disorder characterized by loss of the ability to execute or carry out skilled movements and gestures, despite having the desire and the physical ability to perform them. Apraxia results from dysfunction of the cerebral hemispheres of the brain, especially the parietal lobe, and can arise from many diseases or damage to the brain.

There are several kinds of apraxia, which may occur alone or together. The most common is buccofacial or orofacial apraxia, which causes the inability to carry out facial movements on command such as licking lips, whistling, coughing, or winking. Other types of apraxia include limb-kinetic apraxia (the inability to make fine, precise movements with an arm or leg), ideomotor apraxia (the inability to make the proper movement in response to a verbal command), ideational apraxia (the inability to coordinate activities with multiple, sequential movements, such as dressing, eating, and bathing), verbal apraxia (difficulty coordinating mouth and speech movements), constructional apraxia (the inability to copy, draw, or construct simple figures), and oculomotor apraxia (difficulty moving the eyes on command). Apraxia may be accompanied by a language disorder called aphasia. Corticobasal ganglionic degeneration is a disease that causes a variety of types of apraxia, especially in elderly adult.

Is there any treatment?

Generally, treatment for individuals with apraxia includes physical, speech, or occupational therapy. If apraxia is a symptom of another disorder, the underlying disorder should be treated.

What is the prognosis?

The prognosis for individuals with apraxia varies and depends partly on the underlying cause. Some individuals improve significantly while others may show very little improvement

What research is being done?

The NINDS supports research on movement disorders and conditions such as apraxia. The goals of this research are to increase scientific understanding of these disorders, and to find ways to prevent, treat, and cure them

Article: Childhood Apraxia of Speech
By Shelley L. Velleman
Associate Professor; Communication Disorders, University of Massachusetts at Amherst

General Information for Parents

Childhood apraxia of speech (CAS, also known as DVD — developmental verbal dyspraxia, and DAS — developmental apraxia of speech) is a disorder that is more easily defined by what it is not. It is not a muscle disorder. It is not a cognitive disorder (although it may have some impact on language as well as speech). The problem occurs when the brain tries to tell the muscles what to do — somehow that message gets scrambled. It’s like trying to watch cable t.v. stations without the right descrambler. There is nothing wrong with the t.v. station, and nothing wrong with your set. It’s just that your set can’t read the signal that the station is sending out. The child’s language-learning task is to figure out how to somehow unscramble the mixed message her/his brain is sending to her/his muscles. The visible results (symptoms) of CAS are:

  • little or no babbling in infancy; few consonants
  • understanding of language much better than production of language
  • slow, effortful, or halting speech; sometimes seems to struggle
  • very hard to understand
  • may make slow progress in therapy

CAS has much more effect on volitional (voluntary, creative) speech than on automatic speech. This means that the more your child wants to communicate a particular message, the harder it will be! So, if you happen to hear her/him say something once when there is no pressure, and you say, “Say it again!”, you are guaranteeing that she/he won’t be able to. It is vital to put a minimum of communication pressure on the child. (NOTE: Your child’s speech- language pathologist will need to put communication pressure on the child.) Low-pressure verbal activities are the most important thing a parent can do to help. These include: songs (especially repetitive songs, like Old MacDonald and finger-plays), poems, verbal routines (pat-a-cake, Willoughby Walloby Woo, etc.), repetitive books (such as some of the Mercer-Mayer books, Little Bear, etc.) and daily routines (prayers, social greetings, salute to the flag, etc.). You can make other activities into verbal routines: make up little sayings or poems that you say every time you do the same thing, label instead of counting objects in counting books (“Three dogs: dog, dog, dog”), verbalize repetitive activities (e.g., setting the table: “Plate, plate, plate, plate; fork, fork, fork, fork..”), and so on. Don’t make a big fuss about whether or not your child is talking or singing along; just provide a supportive environment for her/him to do so. Don’t ever say “You can’t have it unless you say it first” — that’s sheer torture for a child with CAS. If your child is unable to communicate effectively right now, the use of sign language or a communication board to supplement speech temporarily not only decreases the frustration but also even seems to help with speech development. Don’t be afraid to try it! Dyspraxia may affect other motor functions (e.g., fine motor control, gross motor planning) and other language functions (e.g., learning grammatical function words like “the, “is”, “or”, etc.; learning more complex grammatical forms like passive; spelling; putting words together into a sentence or sentences together into a paragraph, etc.). Occupational therapy, physical therapy, and learning disabilities assistance are often helpful for children who have these difficulties. CAS can be a very frustrating disorder at times. It is common for children to make progress in “fits and starts” — good progress for a little while, then none, then more, etc. Don’t get discouraged! The therapy is helping, even if you don’t see the effects immediately.

From Pediatric Occupation Therapy Consultants

http://www.kidz-potc.com.sg/2002_01_02.htm

The suck-swallow-breathe synchrony (SSB),[3] serving as the earliest primary motor mechanism, is the rhythmical, coordinated pattern of sucking, swallowing and breathing (Oetter et al., 1993). Being the first motoric pattern that requires timing and sequenced movements, the development of an intact SSB is an important precursor for further sensorimotor and cognitive development including speech and language development, state regulation, postural control, feeding, eye/hand coordination and social/emotional tone (Oetter et al., 1993). Continued clinic work and ad hoc studies has led to increasing awareness of the implications of an inefficient synchrony. Subtle disruptions to the suck-swallow-breathe synchronous pattern are now known to have far reaching impacts on overall sensorimotor development inclusive of postural mechanisms(i.e. midline stability, joint mobility, muscle tone), socio-emotional state, state regulation, eye hand coordination, speech & language(breath support, articulation), and form & space perception. Hence, all assessment and treatment planning should include the evaluation and utilization of SSB components to ensure integrated sensorimotor functioning and behaviour.

The SSB and Postural Development: The progression of coordinated motor skill and movement are dependent upon the foundation/development of a stable base from which to move. That is, without inherent stability or a stable base from which to move, efficient mobility can not take place. Developmentally, as well, the progression of motor function starts proximally (i.e. trunk) before moving distally (i.e. limbs). This is why toddlers first master an awareness of central/midline (truncal) stability before beginning to explore and utilize their hands and legs. With the ability to maintain a stable centered base, the toddler can then orient and move through space with smooth three-dimensional movement patterns in a controlled and graded manner. Mobility patterns such as hopping, running, jumping and even writing are some examples of motor skills requiring mobility superimposed on inherent stability. How does the SSB relate to the development of these?

Take a deep breath and take note of the musculature involved in breathing. Make note of the same when sucking (i.e. sucking a milkshake through a straw) and then blowing (i.e. blowing out candles on a cake). It should be noticed that all three components (suck, blow, breathe) utilized the same musculature that is required for posture and upper extremity function. Therefore, anatomically, it is found that the development of a strong and graded suck helps facilitate jaw, neck and shoulder stability. Similarly, examining the swallow component of the SSB reveals that some of the same musculature used in swallowing is also used in stabilizing the jaw and neck for function. Finally, looking at the breathe component in turn displays the intricate involvement and anatomical attachment of the head, shoulder girdle, ribs and sternum needed for functional respiratory patterns. Therefore, a functional SSB is important for the achievement of mobility superimposed on stability patterns seen in postural and movement patterns (Oetter et al., 1993).

The SSB and Self Regulation: As previously defined, self regulation is the ability to achieve, maintain and change state to match environmental and situational demands. Oral motor means and respiration are inexplicably linked to arousal functionally, anatomically and neurologically. Functionally, many common strategies utilized by adults and children alike to effect changes to their arousal states involve the mouth. While the baby calms him/herself by sucking on the pacifier or thumb, adults choose to chew gum, mouth pens and bite their nails in an attempt to self regulate. Another consideration is one’s breathing patterns. Notice that when one becomes aroused and stressed, respiratory patterns are shallow and fast. To reorganize or calm oneself, it is usually understood that the respiratory rate and depth must be changed. Hence the use of the old adage, “take a deep breath and relax” becomes a familiar phrase during stressful events.

For children that have disrupted SSB synchronies, self regulation difficulties persist resulting in extreme fluctuations in their state of arousals. As such, it is reflected in their disruption of sleep/wake cycles, hyperactivity/hyper-alertness, irritability, inconsolability, restlessness, inattention and behaviour. These often translate to ineffectiveness in and impact on interaction skills, attention, motivation and perception of experiences. Therefore, for these children, the SSB synchrony should be carefully evaluated and considered for treatment purposes.

The SSB and other implications: Survival and growth are obvious functions in the newborn as the mouth plays an integral part in their interaction with the world (communication and exploration) and for survival functions (feeding, state regulation). However, it is also noted that through cranial nerve interaction, the SSB also has influences in the health of one’s eyes and ears. For the eyes, postural implications of a functioning SSB results in the needed neck and midline stability necessary for a stable base from which oculomotor motor control is derived. Through cranial nerve interactions, sucking and blowing also have been noted to contribute strongly to binocular coordination, convergence and accommodation.

With respect to the relation of a proper functioning SSB to a healthier auditory system, the vulnerability to ear and upper respiratory infections are concurrent with those with weak suck/seal/vacuum ability since a strong suck helps in clearing and draining the eustachian tubes in the ears. Without a strong suck, there is limited and infrequent clearing of fluid leading to buildup and bacteria growth that results in chronic ear infections.
Therefore, a by-product of treatment emphasizing improved SSB strength and organization is the reduction in susceptibility to ear and upper respiratory infection and hence general well being.

Conclusion: Pervasive in its implications, the SSB synchrony and its development is now an essential component in assessment and treatment protocols. With clinical foundations supporting the importance of the development of this primitive sensorimotor synchrony and its effects on overall sensorimotor development, its concepts now form an important component in the realm of sensory integration and specifically sensory modulation. Although the understanding of the relationship of the SSB synchrony to other areas of sensorimotor development is still emerging and evolving, its contribution is assured as an important treatment principle for a variety of individuals with sensory integration and/or neuromotor problems.

By Alvin Chan OT(c), OTR
References:

Oetter, P., Richter, E.W., & Frick, S.M. (1993). MORE: Integrating the Mouth With Sensory and Postural Functions. Hugo, MN: PDP Press, Inc.

Ayres, A.J. (1972). Sensory Integration and Learning Disorders. Los Angeles, CA: Western Psychological Services.



[1] Most experts would agree that this is common in developmental disorders as well.

[2] This is why I believe there is a difference between volitional and response oriented suites of circuitry in the brain, that work quite differently in many respects.  I call it the “volition” system, as opposed to a purely response system where learned responses are produced in relationship to specific stimuli or even classes of stimuli.  It is also why I believe that therapies that rely on teaching specific responses (e.g., ABA) may actually ignore voluntary or “self-initiated” and creative types of action.  They are teaching to different systems in the brain, and unless the child is performing in a specific, static form of action or interaction, the volition system must be at least equally addressed (if not more) by the therapy.

[3]     Oetter, P., Richter, E.W., & Frick, S.M. (1993). MORE: Integrating the Mouth With Sensory and Postural Functions. Hugo, MN: PDP Press, Inc.