Apraxia

Apraxia is a brain and nervous system disorder that is characterized by the inability to perform skilled or learned (familiar) movements on command, even though the command is understood and there is a willingness to perform the movement ¹. Both the desire and the capacity to move are present but the person simply cannot execute the act ². Person with apraxia is unable to perform tasks or movements when asked, even though:

• The request or command is understood
• They are willing to perform the task
• The muscles needed to perform the task work properly
• The task may have already been learned

Patients with apraxia cannot use tools or perform such acts as tying shoelaces or button shirts etc. The requirements of daily living are difficult to meet. Apraxia is sometimes also referred to a motor speech disorder that makes it hard to move the mouth in the way needed to produce sounds and words to speak. Apraxia of speech is often present along with another speech disorder called aphasia. Depending on the cause of apraxia, a number of other brain or nervous system problems may be present.

Apraxia is seen in various neurological disorders, including stroke and neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and atypical Parkinsonism [common examples are corticobasal syndrome (CBS); previously termed corticobasal degeneration, or progressive supranuclear palsy (PSP)] ³, ⁴. In patients with left hemispheric stroke, apraxia has been reported to be prevalent in approximately one-third of this population ⁵. In clinical practice, it is not uncommon that more than one type of apraxia is present in a single affected patient ⁶.

Childhood apraxia of speech is sometimes called apraxia of speech, verbal dyspraxia or developmental verbal dyspraxia. A child with childhood apraxia of speech knows what they want to say. The problem is not how the child thinks but how the brain tells the mouth muscles to move. In order for speech to occur, messages need to go from your brain to your mouth. These messages tell the muscles how and when to move to make sounds. When a child has apraxia of speech, the messages do not get through correctly. The child might not be able to move their lips or tongue in the right ways, even though their muscles are not weak. Sometimes, the child might not be able to say much at all.

Apraxia is believed to be caused by a lesion in the neural pathways of the brain that contain the learned patterns of movement ². Apraxia is often a symptom of neurological, metabolic, or other disorders that can involve the brain.

Childhood apraxia of speech or apraxia of speech treatment involves working with a speech therapist to learn how to form the right sounds. The earlier the therapy starts, the better. Treatment works best if done several times a week by a therapist who has experience in apraxia of speech. As time goes on, the person may need therapy less often.

There are different types of therapy programs, depending on the age of the person with apraxia of speech. The treatment aims to teach them how to make certain sounds, words or phrases more clearly. For example, they might be taught to put a finger on their lips when they say the sound ‘p’ to remind them to close their lips.

People with apraxia must practise a lot to get better at speaking. It can be very tiring and frustrating for a child. Seeing a counselor or psychologist might help. People with apraxia may also be seen by a physiotherapist or occupational therapist.

In severe cases, someone with apraxia of speech might need to learn different ways of communicating, such as sign language, using a computer or pointing to a book.

Apraxia and Aphasia

Apraxia is a disorder of the brain and nervous system that is characterized by the inability to perform skilled or learned (familiar) movements on command, even though the command is understood and there is a willingness to perform the movement ¹. Both the desire and the capacity to move are present but the person simply cannot execute the act ². Person with apraxia is unable to perform tasks or movements when asked, even though:

• The request or command is understood
• They are willing to perform the task
• The muscles needed to perform the task work properly
• The task may have already been learned

Aphasia also called dysphasia, is a disturbance in the ability to comprehend or use language caused by damage to the temporal and the frontal lobes of the brain. Aphasia may make it hard for you to understand, speak, read, or write ⁷. Aphasia usually occurs as a result of injury to the language centers of the brain (cerebral cortex). Aphasia is always due to injury to the brain-most commonly from a stroke, particularly in older individuals. However, any type of brain damage can cause aphasia. This includes brain tumors, traumatic brain injury, brain infections and brain disorders that get worse over time. Symptoms vary with the location and extent of the brain tissues involved. Damage to the frontal lobe may result in Broca aphasia. Individuals with this form of aphasia are able to comprehend speech but have great difficulty expressing their thoughts. People with Broca aphasia speak in short phrases that include only nouns and verbs (telegraphic speech). Individuals with Wernicke aphasia, which may result from damage to the temporal lobe, speak in long, garbled sentences (word salad) and have poor speech comprehension. Global aphasia may result from extensive brain damage. Individuals with global aphasia exhibit symptoms of both Broca and Wernicke aphasia.

Brain damage can also cause other problems along with aphasia. You may have muscle weakness in your mouth, called dysarthria. Dysarthria occurs when the muscles used to breath and speak are weakened or paralysed, making speech slurred and hard to understand. You may have trouble getting the muscles of your mouth to move the right way to say words, called apraxia. You can also have swallowing problems, called dysphagia.

Your brain has two halves. Language skills are in the left half of the brain in most people. Damage on the language centers of the brain (left half of the brain in most people) may lead to language problems. Aphasia does not make you less smart or cause problems with the way you think. On the other hand, damage on the right side of your brain may cause other problems, like poor attention or memory.

A person with aphasia may select the wrong words in conversing and may have problems interpreting verbal messages ⁸. Children born with aphasia may not talk at all. Aphasia can be so severe as to make communication with the patient almost impossible, or it can be very mild. Aphasia may affect mainly a single aspect of language use, such as the ability to retrieve the names of objects, or the ability to put words together into sentences, or the ability to read. More commonly, however, multiple aspects of communication are impaired, while some channels remain accessible for a limited exchange of information.

Talking problem in aphasia

You may find that you:

• Can’t think of the words you want to say.
• Say the wrong word. Sometimes, you may say something related, like “fish” instead of “chicken.” Or you might say a word that does not make much sense, like “radio” for “ball.”
• Switch sounds in words. For example, you might say “wish dasher” for “dishwasher.”
• Use made-up words.
• Have a hard time saying sentences. Single words may be easier.
• Put made-up words and real words together into sentences that do not make sense.

Understanding problem in aphasia

You may:

• Not understand what others say. This may happen more when they speak fast, such as on the news. You might have more trouble with longer sentences, too.
• Find it hard to understand what others say when it is noisy or you are in a group.
• Have trouble understanding jokes.

Reading and writing problem in aphasia

You may have trouble with the following things:

• Reading forms, books, and computer screens.
• Spelling and putting words together to write sentences.
• Using numbers or doing math. For example, it may be hard to tell time, count money, or add and subtract.

Generally, aphasia can be divided into four broad categories:

1. Expressive aphasia also called Broca’s aphasia – involves difficulty in conveying thoughts through speech or writing. The person knows what she/he wants to say, but have trouble saying or writing.
2. Receptive aphasia also called Wernicke’s aphasia – involves difficulty understanding spoken or written language. The individual hears the voice or sees the print but cannot make sense of the words.
3. Global aphasia – results from severe and extensive damage to the language areas of the brain. People lose almost all language function, both comprehension and expression. They cannot speak or understand speech, nor can they read or write.
4. Anomic aphasia also called amnesia aphasia – the least severe form of aphasia, have difficulty in using the correct names for particular objects, people, places, or events.

A speech therapist may assess the quality and extent of the Aphasia, and help to educate those people who most commonly interact with the affected individual in methods to help communication.

How does apraxia relate to aphasia?

Both aphasia and apraxia are speech disorders, and both can result from brain injury most often to areas in the left side of the brain. However apraxia is different from aphasia in that it is not an impairment of linguistic capabilities but rather of the more motor aspects of speech production. People with aphasia who also have apraxia may be further limited in their ability to compensate for the speech impairment by using informative gestures.

Types of apraxia

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 ⁹, ¹⁰. Liepmann further classified apraxia into the following major subtypes; ideomotor apraxia, ideational apraxia and limb-kinetic apraxia. Apraxias have also been viewed with regard to task-specificity; task-specific apraxias such as dressing apraxia, sitting apraxia, apraxia of eyelid opening and gait apraxia have been noted ¹¹, ¹², ¹³. However, apraxia of eyelid opening and apraxia of gait are now more strictly considered to be disorders misclassified as apraxia ⁴. Apraxia of eyelid opening is characterized as difficulty with voluntary eye opening. One can test for this by having the patient voluntarily close their eyes, and open instantaneously when the examiner shouts “open!” The patient with apraxia of eyelid opening will not be able to open the eyes immediately. This disorder can be misdiagnosed as focal eye dystonia or blepharospasm, conditions where there is forceful eye closure. Apraxia of gait is a somewhat nonspecific term often used to refer to various gait patterns, including gait ignition failure and freezing of gait. The pathophysiology of these disorders is not well understood, although some studies have found brain regions relevant in other types of apraxia to be involved in apraxia of eyelid opening, suggesting that these disorders may share common neural systems.

Apraxia comes in several different forms:

Limb-kinetic apraxia

Limb-kinetic apraxia is the inability to make precise or exact movements with a finger, an arm or a leg, resulting in inaccurate or clumsy movements ¹⁴. An example is the inability to use a screwdriver, buttoning or coin rotation notwithstanding that the person affected understands what is to be done and has done it in the past ¹⁵.

Ideomotor apraxia

Ideomotor apraxia is a subtype of apraxia that is commonly seen in patients with stroke or neurodegenerative disorders ¹. Ideomotor apraxia is the inability to carry out a command from the brain to mimic limb or head movements performed or suggested by others, 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”).

Conceptual apraxia

Conceptual apraxia is much like ideomotor ataxia but infers a more profound malfunctioning in which the function of tools is no longer understood.

Ideational apraxia

Ideational apraxia is the inability to create a plan for a specific movement. Ideational apraxia 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.

Buccofacial apraxia

Buccofacial apraxia also known as facial-oral apraxia, is the inability to coordinate and carry out facial and lip movements such as whistling, winking, coughing etc on command. This form includes verbal or speech developmental apraxia, perhaps the most common form of apraxia.

Constructional apraxia

Constructional apraxia affects the person’s ability to draw or copy simple diagrams or to construct simple figures.

Oculomotor apraxia

Oculomotor apraxia is a condition in which patients find it difficult to move their eyes.

Apraxia of eyelid opening

Apraxia of eyelid opening is defined as “nonparalytic inability to open the eyes at will in the absence of visible contraction of the orbicularis oculi muscle” ¹⁶. There is an inability of voluntary eye reopening without an orbicularis oculi spasm despite sustained frontalis contraction. It is most commonly associated with blepharospasm (persistent focal dystonia, with eyelid muscle contraction). Very rarely, it can occur as an isolated idiopathic phenomenon ¹⁷. Apraxia of eyelid opening patients typically presents with the inability to open the eyelids following either voluntary or involuntary lid closure. Eye opening is, however, typically normal after reflex blinking ¹⁸. Additionally, forceful contraction of the frontalis muscle upon attempted opening has been reported as a feature of apraxia of eyelid opening, though it is not present in all cases. Apraxia of eyelid opening is often accompanied by blepharospasm, though case reports do exist of isolated apraxia of eyelid opening without the presence of blepharospasm. In patients with essential blepharospasm, the combination of spasmodic closure of the eyelids and levator inhibition cause difficulty with opening the lids after forced closure ¹⁶.

Elevation of the eyelid involves simultaneous activation of the levator palpebrae superioris muscle and inhibition of the orbiculares oculi muscle ¹⁹. Apraxia of eyelid opening can result from involuntary inhibition of levator function, prolonged contraction of the orbicularis, or both ²⁰. The classic finding of inability to open the lids after closure is postulated to be caused by persistent contraction of the activated orbicularis oculi muscle ²¹.

Tozlovanu et al ²² studied the role of orbicularis contraction in apraxia of eyelid opening by using electromyography to measure orbicularis activity and latency of lid opening. This study demonstrated a strong correlation between time to orbicularis oculi inhibition and the completion of lid opening in both the control group and the study group (patients with apraxia of eyelid opening), with an abnormal persistence of orbicularis oculi function present in 10 of the 11 patients with apraxia of eyelid opening ²².

Though apraxia of eyelid opening has been described in isolation, it is also associated with other conditions such as benign essential blepharospasm, progressive supranuclear palsy, dystonic parkinsonian syndrome/parkinsonism, motor neuron disease, and Shy-Drager syndrome ²³, ²⁴, ²⁵. Apraxia of eyelid opening has also been associated with central nervous system (CNS) lesions in various locations, including the non-dominant hemisphere, medial frontal lobe, basal ganglia, and rostral brain stem ²⁶, ²⁷, ²⁸, ²⁹, ³⁰. Additionally, isolated case reports of medication-induced apraxia of eyelid opening (including lithium, sulpiride, and MPTP), as well as sleep-induced apraxia of eyelid opening, exist in the literature ²⁹, ³⁰, ³¹, ³².

Historically, the mainstay of treatment for apraxia of eyelid opening (with or without concurrent blepharospasm) has been injection of botulinum toxin into the pre-tarsal orbicularis oculi muscle ³³. Other treatment options including levodopa ³⁴, trihexyphenidyl ³⁵ and valproic acid ³⁶ have been described in the literature, although results are limited.

Several reports exist detailing the successful use of frontalis suspension ³⁷, ³⁸ and upper eyelid myectomy ³⁹ as surgical alternatives for some patients with apraxia of eyelid opening. These procedures have also been described in combination with medical therapy ⁴⁰.

Apraxia of speech

Apraxia of speech is a rare type of speech disorder that makes it difficult to move the mouth in the way needed to produce sounds and words. Apraxia of speech is a neurological disorder that affects the brain pathways involved in planning the sequence of movements involved in producing speech. The brain knows what it wants to say, but cannot properly plan and sequence the required speech sound movements. Apraxia of speech is defined as a “neurologic speech disorder that reflects an impaired capacity to plan or program sensorimotor commands necessary for directing movements that result in phonetically and prosodically normal speech” ⁴¹. Apraxia of speech occurs when the brain can’t move the mouth, lips, jaw and tongue properly. Even though they know what they want to say, people with apraxia of speech have problems pronouncing sounds, syllables and words.

Apraxia of speech has also been referred to in the clinical literature as acquired apraxia of speech, verbal apraxia, dyspraxia or childhood apraxia of speech (CAS) when diagnosed in children ⁴².

The severity of apraxia of speech varies from person to person. It can be so mild that it causes trouble with only a few speech sounds or with pronunciation of words that have many syllables. In the most severe cases, someone with apraxia of speech might not be able to communicate effectively by speaking, and may need the help of alternative communication methods.

Apraxia of speech can be divided into two types based on what caused the condition:

1. Childhood apraxia of speech. Childhood apraxia of speech is present from birth. This condition is also known as developmental apraxia of speech, developmental verbal apraxia, or articulatory apraxia. Childhood apraxia of speech is not the same as developmental delays in speech, in which a child follows the typical path of speech development but does so more slowly than is typical. The causes of childhood apraxia of speech are not well understood. Imaging and other studies have not been able to find evidence of brain damage or differences in the brain structure of children with apraxia of speech. Children with apraxia of speech often have family members who have a history of a communication disorder or a learning disability. This observation and recent research findings suggest that genetic factors may play a role in the disorder. Childhood apraxia of speech appears to affect more boys than girls.
   
2. Acquired apraxia of speech. Acquired apraxia of speech can affect someone at any age, although it most typically occurs in adults. Acquired apraxia of speech is caused by damage to the parts of the brain that are involved in speaking and involves the loss or impairment of existing speech abilities. It may result from a stroke, head injury, tumor, or other illness affecting the brain. Acquired apraxia of speech may occur together with other conditions that are caused by damage to the nervous system. One of these is dysarthria, as mentioned earlier. Another is aphasia, which is a language disorder. 
   

Apraxia of speech is not caused by weakness or paralysis of the speech muscles (the muscles of the jaw, tongue, or lips). Weakness or paralysis of the speech muscles results in a separate speech disorder, known as dysarthria. Some people have both dysarthria and apraxia of speech, which can make diagnosis of the two conditions more difficult.

Apraxia is differentiated from dysarthria in that it is not due to problems in strength, speed, and coordination of the articulatory musculature. The primary behavioral characteristics of apraxia of speech are slowed speech, abnormal prosody, distortions of speech sounds such as sound substitutions and highly inconsistent errors. Individuals with apraxia of speech often appear to be groping for the right way to position their mouth, tongue and lips (articulators) when producing words and sounds.

Apraxia of speech is usually noticed when a child is first learning to talk, but it can continue into adulthood. In adults, it can be caused by a brain injury or dementia.

At present, the diagnosis of apraxia of speech remains purely behavioral, based primarily on perceptual evaluation of speech characteristics without evaluation of brain tissue damage. This sometimes may result in confounding disorders with shared behavioral symptoms. However, in future apraxia evaluation may change as more is understood about what type of brain damage causes apraxia of speech and diagnosis may rely more heavily on evaluation of specific damage to brain regions important for speech.

There are no reliable data on the incidence and prevalence apraxia of speech in adults due to challenges associated with the common co-occurrence of apraxia of speech with aphasia and dysarthria ⁴³. Collection of data is also challenging due to difficulty distinguishing among those disorders—particularly in distinguishing between apraxia of speech characteristics and phonological errors that can occur in aphasia ⁴⁴.

McNeil et al. ⁴⁵ suggest that isolated apraxia of speech (i.e., apraxia of speech in the absence of dysarthria or aphasia) is very uncommon. Duffy ⁴⁶ observed that apraxia of speech was documented as the primary, but not necessarily the only, communication disorder for 6.9% of all motor speech disorders in the Mayo Clinic Speech Pathology practice. This percentage would undoubtedly increase drastically if the data included cases in which apraxia of speech was a secondary communication disorder (e.g., less severe than aphasia or dysarthria) ⁴⁶.

Types and causes of apraxia of speech

There are two main types of apraxia of speech:

1. Acquired apraxia of speech
2. Childhood apraxia of speech.

Childhood apraxia of speech

Childhood apraxia of speech is sometimes called verbal dyspraxia or developmental verbal dyspraxia. A child with childhood apraxia of speech knows what they want to say. The problem is not how the child thinks but how the brain tells the mouth muscles to move. Apraxia of speech is very rare, and only affects 1 or 2 children in every 1,000 who visit a speech pathologist.

Even though the word “developmental” is used, childhood apraxia of speech is not a problem that children outgrow. A child with childhood apraxia of speech will not learn speech sounds in typical order and will not make progress without treatment. It can take a lot of work, but the child’s speech can improve.

A speech therapist with experience evaluating and treating children with apraxia can test your child’s speech and language. The speech therapist will test how well your child understands language (receptive language) as well as the type and length of utterance he/she uses (expressive language). To test for childhood apraxia of speech, the speech therapist will look at your child’s oral-motor skills, motor speech skills, and speech melody (prosody).

Childhood apraxia of speech causes

Most of the time, the cause of childhood apraxia of speech is unknown. In some cases, damage to the brain causes childhood apraxia of speech. Damage may be caused by a genetic disorder or syndrome, or by a stroke or traumatic brain injury. Apraxia of speech has been linked to some disorders, including Down syndrome, autism spectrum disorder, Koolen de Vries syndrome, floating harbour syndrome and 16p11.2 deletion syndrome.

Childhood apraxia of speech signs and symptoms

Not all children with childhood apraxia of speech are the same. Your child may show some or all of the signs below. You should talk to your doctor and see an speech language pathologist if your child is older than 3 years and:

• does not always say words the same way every time;
• tends to put the stress on the wrong syllable or word;
• distorts or changes sounds; or
• can say shorter words more clearly than longer words.

Children with childhood apraxia of speech may have other problems, including:

• problems feeding as a baby;
• babbling less than other babies;
• not learning to talk as quickly as other babies their own age;
• difficulty with fine motor skills;
• being very hard to understand, even by their own families;
• delayed language;
• speaking more slowly than other children of their age;
• visibly struggling to move their lips or tongue when trying to make a sound;
• emphasizing the wrong part of a word;
• problems with reading, spelling, and writing;
• dropping or adding sounds to words (like ‘umbararella’ for ‘umbrella’);
• having a very limited vocabulary;
• struggling to form words or sounds;
• making different mistakes when they try to say the same words;
• having difficulty with intonations (speaking in a monotone or stressing the wrong part of words)

Apraxia of speech can be very frustrating because it prevents people from communicating properly. Children with the condition are more likely to have reading and spelling difficulties, and may also have problems controlling both their small and large muscle movements. Sometimes they may also have other learning difficulties.

Childhood apraxia of speech treatment

Children with apraxia of speech will not outgrow the problem on their own. Children with apraxia of speech also do not acquire the basics of speech just by being around other children, such as in a classroom. Therefore, speech-language therapy is necessary for children with apraxia of speech as well as for people with acquired apraxia of speech who do not spontaneously recover all of their speech abilities.

A child with childhood apraxia of speech should work with a speech-language pathologist. Speech-language pathologists use different approaches to treat apraxia of speech, and no single approach has been proven to be the most effective. Therapy is tailored to the individual and is designed to treat other speech or language problems that may occur together with apraxia of speech. Frequent, intensive, one-on-one speech-language therapy sessions are needed for both children and adults with apraxia of speech. The repetitive exercises and personal attention needed to improve apraxia of speech are difficult to deliver in group therapy. Children with severe apraxia of speech may need intensive speech-language therapy for years, in parallel with normal schooling, to obtain adequate speech abilities.

Your child may begin with therapy 3–5 times per week. As speech improves, treatment may be less often. Individual or group therapy may be appropriate at different stages of treatment.

The goal of treatment is to help your child say sounds, words, and sentences more clearly. Your child will learn how to:

• plan the movements needed to say sounds and
• make those movements the right way at the right time.

Doing exercises to make the mouth muscles stronger will not help. Mouth muscles are not weak in children with childhood apraxia of speech. Working on how to move those muscles to say sounds will help.

Your child must practice speaking to get better at it. It helps to use all the senses when learning how to say sounds. Your child may use:

• “touch” cues, like putting their finger on their lips when saying the “p” sound as a reminder to close the lips;
• “visual” cues, like looking into a mirror when making sounds; or
• “listening” cues, like practicing sounds with a recorder and then listening to hear if the sounds were made correctly.

In order to communicate, your child may learn sign language or may learn to use picture boards or computers that talk. This is called augmentative and alternative communication (AAC).

Some parents are afraid that their child will only want to use augmentative and alternative communication (AAC) systems and not try to talk. There is no evidence to support this idea. Augmentative and alternative communication systems support communication and help your child as they work on their speech with the speech-language pathologist.

Childhood apraxia of speech treatment takes time, and your child will need your support. Practice what your child learns with the speech-language pathologist to help them make progress. Take breaks when your child is tired and make practice as much fun as possible. Tell your child’s speech-language pathologist what happens at home so you can all work together to help your child succeed.

Acquired apraxia of speech

Acquired apraxia of speech typically results from brain injury in people who have already learned how to speak. Acquired apraxia of speech can affect someone at any age, although it most typically occurs in adults. Damage to a wide range of brain areas has been associated with the disorder, mostly in the left hemisphere.

Developmental apraxia of speech begins very early in life and in many cases may be genetic. As a result, developmental apraxia of speech is characterized not only by symptoms seen in acquired apraxia of speech, but also by a multitude of other developmental issues.

Acquired apraxia of speech is caused by any process or condition that compromises the structures and pathways of the brain responsible for planning and programming motor movements for speech. Acquired apraxia of speech most common causes often include:

• stroke,
• traumatic brain injury (TBI),
• brain tumor,
• surgical trauma (e.g., brain tumor resection), or
• progressive disease.

Occasionally, apraxia of speech is the first, only, or most prominent symptom in degenerative conditions (e.g., corticobasal degeneration, progressive supranuclear palsy). The term primary progressive apraxia of speech is used in such cases ⁴⁷.

Primary progressive apraxia of speech

Primary progressive apraxia of speech can be defined broadly as apraxia of speech due to a neurodegenerative condition that can occur in isolation or with various combinations and degrees of aphasia, nonaphasic cognitive impairments, and sensorimotor deficits that do or do not meet criteria for a more specific neurodegenerative condition (e.g., corticobasal syndrome, progressive supranuclear palsy) ⁴⁷. Primary progressive apraxia of speech can be more narrowly defined as apraxia of speech of insidious onset and gradual progression, in the absence of more than equivocal evidence of aphasia, nonaphasic cognitive impairments or sensorimotor deficits that meet criteria for another specific neurodegenerative disease or other explanatory condition at the time of diagnosis ⁴⁷. Dysarthria can be present but cannot be more severe than the apraxia of speech at presentation. There is no clear consensus about diagnostic labeling when different degrees of both apraxia of speech and aphasia are present, or when a patient with primary progressive apraxia of speech eventually evolves to meet criteria for another neurodegenerative disease ⁴⁷. If aphasia emerges in someone with primary progressive apraxia of speech, or both disorders are initially present but the apraxia of speech predominates, the designation dominant apraxia of speech (DAOS) has been used ⁴⁸; this seems justified by neuroimaging in which dominant apraxia of speech (DAOS) appears more like that associated with primary progressive apraxia of speech than nonfluent variant of primary progressive aphasia, with or without apraxia of speech ⁴⁸.

Diagnosis of primary progressive apraxia of speech is not always easy and can range from confident, probable, or possible to recognition of a not-otherwise-specifiable neurological communication disorder, to a misdiagnosis of primary progressive aphasia, with or without apraxia of speech, dysarthria, or psychogenic disturbance ⁴⁷. Misdiagnoses can occur across the severity spectrum but are more common when speech difficulty is mild. Evaluation over time may be necessary before a confident diagnosis can be made.

Apraxia signs and symptoms

The major symptom of apraxia is a person’s inability to perform movement in the absence of any physical paralysis. A person with apraxia is unable to put together the correct muscle movements. Commands to move are understood, but cannot be executed. When movement is initiated, it is usually very clumsy, uncontrolled and inappropriate. In some cases, movement may occur unintentionally. The person is often aware of the mistake. Apraxia is sometimes accompanied by a person’s loss of ability to comprehend or use words (Aphasia).

People with either form of apraxia of speech may have a number of different speech characteristics, or symptoms:

• Distorted, repeated, or left out speech sounds or words. People with apraxia of speech may have difficulty pronouncing words correctly. Sounds, especially vowels, are often distorted. Because the speaker may not place the speech structures (e.g., tongue, jaw) quite in the right place, the sound comes out wrong. Longer or more complex words are usually harder to say than shorter or simpler words. Sound substitutions might also occur when apraxia of speech is accompanied by aphasia. The person also has difficulty putting words together in the correct order.
• Struggling to pronounce the right word
• Groping for sounds. People with apraxia of speech often appear to be groping for the right sound or word, and may try saying a word several times before they say it correctly.
• More difficulty using longer words, either all the time, or sometimes
• Making inconsistent errors in speech. For example, someone with apraxia of speech may say a difficult word correctly but then have trouble repeating it, or may be able to say a particular sound one day and have trouble with the same sound the next day.
• Ability to use short, everyday phrases or sayings (such as “How are you?”) without a problem
• Making errors in tone, stress, or rhythm. Another common characteristic of apraxia of speech is the incorrect use of prosody. Prosody is the rhythm and inflection of speech that you use to help express meaning. Someone who has trouble with prosody might use equal stress, segment syllables in a word, omit syllables in words and phrases, or pause inappropriately while speaking.
• Better writing ability than speaking ability
• Children with apraxia of speech generally understand language much better than they are able to use it. Some children with the disorder may also have other speech problems, expressive language problems, or motor-skill problems.

Specific types of apraxia are characterized by an inability to perform particular movements on command. For example, in Buccofacial Apraxia or orofacial apraxia, an affected individual is unable to cough, whistle, licking the lips, sticking out the tongue or wink when asked. In Constructional Apraxia, an individual is unable to reproduce simple patterns or copy simple drawings.

Other forms of apraxia include ⁴⁹:

• Ideational apraxia. Inability to carry out learned, complex tasks in the proper order, such as putting on socks before putting on shoes.
• Ideomotor apraxia. Inability to voluntarily perform a learned task when given the necessary objects. For instance, if given a screwdriver, the person may try to write with it as if it were a pen.
• Limb-kinetic apraxia. Difficulty making precise movements with an arm or leg. It becomes impossible to button a shirt or tie a shoe. In gait apraxia, it becomes impossible for a person to take even a small step. Gait apraxia is commonly seen in normal pressure hydrocephalus.

Apraxia causes

Apraxia is caused by damage to the brain, a defect in the brain pathways that contain memory of learned patterns of movement. The lesion may be the result of certain metabolic, neurological or other disorders that involve the brain, particularly the frontal lobe (inferior parietal lobule) of the left hemisphere of the brain. In this region, complex, 3-dimensional representations of previously learned patterns and movements are stored. Patients with apraxia cannot retrieve these models of stored skilled movements.

When apraxia develops in a person who was previously able to perform the tasks or abilities, it is called acquired apraxia.

The most common causes of acquired apraxia are:

• Brain tumor
• Condition that causes gradual worsening of the brain and nervous system (neurodegenerative illness)
• Dementia
• Stroke
• Traumatic brain injury
• Hydrocephalus

Apraxia may also be seen at birth. Symptoms appear as the child grows and develops. The cause is unknown.

Oculomotor apraxia is a dominant genetic trait. The gene for this condition has been mapped to chromosome 2p13. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 2p13” refers to band 13 on the short arm of chromosome 2. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

Genetic diseases are determined by two genes, one received from the father and one from the mother. Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

Tissue or cellular damage (lesions) to other specific parts of the brain, whether as a result of stroke or wounds, tumors, or dementias, may also cause apraxia. These other locations include the so-called supplementary motor area (premotor cortex) or corpus callosum.

Since apraxia may accompany dementia or stroke, it is more frequently diagnosed among older persons. If apraxia is the result of a stroke it usually abates within weeks.

Some cases of apraxia are congenital. When a child is born with apraxia it is usually the result of malformations of the central nervous system. At the other extreme, individuals with deteriorating intellectual functioning (degenerative dementia) may also develop apraxia.

Individuals with a condition of deteriorating intellectual functioning (degenerative dementia) may also develop apraxia.

Apraxia neurophysiology

Much of today’s fundamental knowledge on apraxia is based on classic observations made in clinical practice ¹. As apraxia is present in patients with chronic left hemispheric strokes and Alzheimer’s disease, these patient populations are often targets of study with regard to this phenomenon ⁵⁰, ⁵¹, ⁵². Some patients with lesions involving the corpus callosum such as those following a callosotomy, have been noted to be apraxic with regard to the left hand, but not the right. These observations indicate that the left hemisphere is relevant for praxis, and that it may be due to retrieval of representations stored in this hemisphere ⁶. Patients may also be differentially affected depending on the type of neurological disorder. For example, patients with left hemispheric stroke have been noted to have more difficulties with pantomiming and transitive movements, and less with imitating gestures and intransitive movements. Other studies report that whereas patients with left brain damage appear to have difficulties with tool use but intact knowledge regarding function and gestures, patients with Alzheimer’s disease show deficits in function and gestures but preserved tool use ⁵⁰, ⁵³, ⁵⁴.

Praxis movements are complex, involving different aspects of cognition and movement; consequently, several brain regions are considered to be relevant. The conceptual knowledge for actions appears to involve brain regions such as the left premotor, prefrontal, middle temporal and parietal areas ⁵⁵. Neuroimaging studies such as those using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have probed the neural correlates of praxis, with studies widely varying in which aspect of praxis to focus on. Functional neuroimaging studies have shown that the left temporal lobe is involved in retrieval of semantic memory that plays a role in praxis ⁵⁶, ⁵⁷. Evidence also suggests that the left premotor cortex is also involved in retrieval of knowledge regarding tools and their actions ⁵⁸, ⁵⁹. The left inferior and/or superior parietal lobule have also been shown to be involved in grasping movements aimed at tools ⁶⁰, ⁶¹. The parietal cortex appears to be relevant in the integration of perceptual spatiotemporal information as well, such as estimating whether two objects of different sizes may collide with each other, or selecting which grasp to use when a particular object can be used in various ways (e.g., knife to stab, or slice bread) ⁶², ⁶⁰. Functional imaging studies suggest that there is a stronger left lateralization in posterior parietal and premotor cortices for planning intransitive movements ⁶³, ⁶⁴.

Anatomical studies have further shown interconnections between these praxis-relevant brain regions, such as connections among the supramarginal gyrus with the ventral premotor cortex, inferior frontal gyrus, middle temporal gyrus and intraparietal areas ⁶⁵, ⁶⁶. Moreover, electroencephalography (EEG) studies have confirmed parietal and sensorimotor activity to occur prior to the onset of praxis movements, in contrast with premotor and sensorimotor activity seen prior to simple movements ⁶⁷, ⁶⁸.

Reports on the location of brain lesions in specific subtypes of apraxia are available, allowing one to ponder on the underlying pathophysiology of various major subtypes of apraxia. For example, ideomotor apraxia has been found to occur in left hemispheric stroke patients with injury to the premotor cortex, supplementary motor cortex, inferior parietal lobe or corpus callosum. Relevant brain regions for ideational apraxia, a disorder characterized by difficulty with conceptualization and sequencing deficits, are likely comprised of the left premotor, prefrontal, middle temporal and parietal areas ⁵⁵. Investigations on patients with limb-kinetic apraxia have found that brain region relevant to grasp, chiefly, the contralateral premotor cortex, is affected ⁶⁹. Studies on healthy human subjects performing precision grip also complement these findings, supporting the theoretical notion that the contralateral premotor cortex, specifically, the ventral portion, is relevant in the pathophysiology of limb-kinetic apraxia ⁷⁰. In essence, the findings obtained from functional, anatomical and neurophysiological studies collectively suggest that the parieto-premotor-frontal network appears to be critical for both preparation and the execution of praxis movements ⁷¹.

Investigation of praxis-relevant brain areas has also been conducted using noninvasive brain stimulation. Disruption of neural activity using repetitive transcranial magnetic stimulation (rTMS) has been found to alter semantic knowledge, an essential component of praxis. In healthy human subjects, low-frequency repetitive transcranial magnetic stimulation (rTMS) (1 Hz for 10 minutes at 120% motor threshold) delivered to the anterior temporal lobe resulted in a category-general impairment (slowed performance for picture naming in both living and nonliving objects), whereas inferior parietal lobule stimulation induced a category-specific deficit for objects (slowed performance for nonliving objects only) ⁷². Therefore, these study results support that brain regions are differentially involved in praxis, and are likely relevant in patients with apraxia who are selectively impaired with regard to category-specific or category-general knowledge. Such patients with sematic impairment have been identified in those with mild cognitive impairment or Alzheimer’s disease ⁷³, ⁷⁴.

Apraxia has also been identified in movement disorders where the basal ganglia are involved such as Parkinson’s disease, corticobasal degeneration and progressive supranuclear palsy ⁷⁵, ⁷⁶. Even in the early stages of Parkinson’s disease, difficulty with praxis has been identified, which appear to correlate with an activation shift from left parietal to left frontal areas shown on fMRI ⁷⁷. The limb-kinetic apraxia found in patients with Parkinson’s disease appears to be largely independent from bradykinesia or other symptoms, once again indicating that the problem appears to be one concerning dexterity ¹⁴. These findings imply that the basal ganglia also play a role in praxis, and that it is not only cortical structures that are involved in this process. Corticobasal degeneration and progressive supranuclear palsy, both types of atypical Parkinsonism, are tauopathies, with pathological cells present mainly in the cortex in corticobasal degeneration and subcortically in progressive supranuclear palsy ⁷⁵. In corticobasal degeneration, ideomotor and/or limb-kinetic apraxia have been reported, whereas ideomotor apraxia has been identified in progressive supranuclear palsy ⁷⁵, ⁷⁸, ⁷⁹. These reports support the theoretical notion that both cortical and subcortical brain regions play a role in praxis.

Apraxia prevention

Reducing your risk of stroke and brain injury may help prevent conditions that lead to apraxia ⁸⁰.

Apraxia complications

Having apraxia may lead to:

• Learning problems
• Low self-esteem
• Social problems

Apraxia diagnosis

You should see a doctor if you or your child is having trouble speaking or understanding what people say. A doctor will determine if there is a medical cause for your problem. Professionals known as speech-language pathologists play a key role in diagnosing and treating apraxia of speech. A speech-language pathologist will test your speech and language skills. Because there is no single symptom or test that can be used to diagnose apraxia of speech, the person making the diagnosis generally looks for the presence of several of a group of symptoms, including those described earlier. Ruling out other conditions, such as muscle weakness or language production problems (e.g., aphasia), can help with the diagnostic process.

The speech-language pathologist will ask you about the problems you have and what you want to work on. The speech-language pathologist will test how well you:

• Understand words, questions, directions, and stories.
• Say words and sentences. The speech-language pathologist will ask you to name objects, describe pictures, and answer questions.
• Read and write. The speech-language pathologist will have you write letters, words, and sentences. You will also read short stories and answer questions about them.
• Find other ways to share your ideas when you have trouble talking. This may include pointing or using other gestures and drawing pictures.

In formal testing for both acquired and childhood apraxia of speech, a speech-language pathologist may ask the patient to perform speech tasks such as repeating a particular word several times or repeating a list of words of increasing length (for example, love, loving, lovingly). For acquired apraxia of speech, a speech-language pathologist may also examine the patient’s ability to converse, read, write, and perform nonspeech movements. To diagnose childhood apraxia of speech, parents and professionals may need to observe a child’s speech over a period of time.

The following tests may be done if the cause of the disorder is not known:

• CT or MRI scans of the brain may help show a tumor, stroke, or other brain injury.
• An electroencephalogram (EEG) may be used to rule out epilepsy as a cause of the apraxia.
• A spinal tap or lumbar puncture may be done to check for inflammation or an infection that affects the brain.

Standardized language and intellectual tests should be done if apraxia of speech is suspected. Testing for other learning disabilities may also be needed.

Apraxia treatment

When apraxia is a symptom of an underlying disorder, that disease or condition must be treated. To date, there is no standardized treatment for apraxia that is available ¹. Therapeutic efforts have been mostly concentrated in affected stroke patients with or without concomitant aphasia, as the relative frequency of limb apraxia has been reported to be approximately 51% in patients with left hemispheric stroke ⁸¹, ⁸². In these studies, rehabilitative treatment for apraxia was conducted three times weekly, each lasting 50 minutes and conducted over 30 sessions ⁸¹. 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 ⁸². 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 ⁸³. 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.

Physical and occupational therapy may be of benefit to stroke and head injured patients. When apraxia is a symptom of another neurological disorder, the underlying condition must be treated. In some cases, children with apraxia may learn to compensate for deficits as they grow older with the help of special education and physical therapy programs.

Speech therapy and special education may be particularly helpful in treating patients with developmental apraxia of speech.

During treatment, speech therapists will focus on:

• Repeating sounds over and over to teach mouth movements
• Slowing down the person’s speech
• Teaching different techniques to help with communication

Recognition and treatment of depression is important for people with apraxia.

To help with communication, family and friends should:

• Avoid giving complex directions.
• Use simple phrases to avoid misunderstandings.
• Speak in a normal tone of voice. Speech apraxia is not a hearing problem.
• Do not assume that the person understands.
• Provide communication aids, if possible, depending on the person and condition.

Other tips for daily living include:

• Maintain a relaxed, calm environment.
• Take time to show someone with apraxia how to do a task, and allow enough time for them to do so. Do not ask them to repeat the task if they are clearly struggling with it and doing so will increase frustration.
• Suggest other ways to do the same things. For example, buy shoes with a hook and loop closure instead of laces.

If depression or frustration is severe, mental health counseling may help.

Apraxia of speech treatment

In some cases, people with acquired apraxia of speech recover some or all of their speech abilities on their own. This is called spontaneous recovery.

Children with apraxia of speech will not outgrow the problem on their own. They also do not acquire the basics of speech just by being around other children, such as in a classroom. Therefore, speech-language therapy is necessary for children with apraxia of speech as well as for people with acquired apraxia of speech who do not spontaneously recover all of their speech abilities.

Speech-language pathologists use different approaches to treat apraxia of speech, and no single approach has been proven to be the most effective. Therapy is tailored to the individual and is designed to treat other speech or language problems that may occur together with apraxia of speech. Frequent, intensive, one-on-one speech-language therapy sessions are needed for both children and adults with apraxia of speech. The repetitive exercises and personal attention needed to improve apraxia of speech are difficult to deliver in group therapy. Children with severe apraxia of speech may need intensive speech-language therapy for years, in parallel with normal schooling, to obtain adequate speech abilities.

In severe cases, adults and children with apraxia of speech may need to find other ways to express themselves. These might include formal or informal sign language; a notebook with pictures or written words that can be pointed to and shown to other people; or an electronic communication device—such as a smartphone, tablet, or laptop computer—that can be used to write or produce speech. Such assistive communication methods can also help children with apraxia of speech learn to read and better understand spoken language by stimulating areas of the brain involved in language and literacy.

Some adults and children will make more progress during treatment than others. Support and encouragement from family members and friends and extra practice in the home environment are important.

Transcranial direct current stimulation

In two double-blind studies, Marangolo et al ⁸⁴, ⁸⁵ showed that using transcranial direct current stimulation as an add-on to speech production therapy increased production accuracy, beyond the gains made from the therapy with sham stimulation. However, both studies were limited in sample size (three and eight individuals) and gains varied across participants. Moreover, these studies tested individuals with chronic apraxia of speech. There are no published studies that have investigated the use of transcranial direct current stimulation in early phases of apraxia of speech recovery, though the few that have considered transcranial direct current stimulation for early stages of stroke recovery suggest that its use is promising for improving plasticity at the subacute stage ⁸⁶, ⁸⁷.

Self-administered computer treatment

The ubiquitous use of smartphones and tablet devices has resulted in the development of applications that patients can download and use in addition to (or following discharge from) speech-language rehabilitation services. There is some positive evidence for the use of computerized treatment to improve naming and repetition in individuals with apraxia of speech and concomitant aphasia. Using a randomized controlled trial that included 50 participants, Varley et al ⁸⁸ showed gains in naming and repetition that were directly proportional to the amount of time participants used the program. This study provides support for the use of computerized treatment for apraxia of speech; however, at this time, there are no studies that have evaluated whether research-backed approaches for apraxia of speech (e.g., articulatory/kinematic) can be successfully delivered via computer or tablet. Further, no studies have assessed the efficacy of computerized treatment for apraxia of speech at the acute or subacute stage, when stamina for treatment may be complicated by other factors. Nevertheless, using commercially available apps to deliver speech-language therapy may be a feasible supplement to traditional speech therapy in early phases of recovery ⁸⁹.

Apraxia prognosis

Many people with apraxia are no longer able to be independent and may have trouble performing everyday tasks. Ask the health care provider which activities may or may not be safe. Avoid activities that may cause injury and take the proper safety measures.

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