Apraxia

Apraxia is a neurological disorder as a non-motor abnormality characterized by the patient’s difficulty in eyelid elevation bilaterally inability of voluntary eye reopening without an orbicularis oculi spasm despite sustained frontalis contraction characterized by the inability to perform learned (familiar) movements on command, even though the command is understood and there is a willingness to perform the movement. Both the desire and the capacity to move are present but the person simply cannot execute the act.

Apraxia of speech (AOS)—also known as acquired apraxia of speech, verbal apraxia, or childhood apraxia of speech (CAS) when diagnosed in children—is a speech sound disorder. Someone with AOS has trouble saying what he or she wants to say correctly and consistently. AOS 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.

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. Patients whose ability to speak is interrupted (aphasia) but who are unaffected by apraxia can live a relatively normal life; those with significant apraxia are almost invariably dependent.

Types

Apraxia comes in several different forms:

Limb-kinetic apraxia – is the inability to make precise movements with a finger, an arm, or a leg. An example is the inability to use a screwdriver notwithstanding that the person affected understands what is to be done and has done it in the past.
Ideomotor apraxia – is the inability to carry out a command from the brain to mimic limb or head movements performed or suggested by others.
Conceptual apraxia – is much like ideomotor ataxia but infers a more profound malfunctioning in which the function of tools is no longer understood.
Buccofacial apraxia – (sometimes called 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 the disorder.
Constructional apraxia – affects the person’s ability to draw or copy simple diagrams or to construct simple figures.
Apraxia of speech (AOS) – Difficulty planning and coordinating the movements necessary for speech (e.g. Potato=Totapo, Topato).^[rx] AOS can independently occur without issues in areas such as verbal comprehension, reading comprehension, writing, articulation, or prosody.^[rx]
Orofacial apraxia 0 This is the most common type of apraxia and is the inability to carry out facial movements on demand. For example, an inability to lick one’s lips, wink, or whistle when requested to do so. This suggests an inability to carry out volitional movements of the tongue, cheeks, lips, pharynx, or larynx on command.^[rx]^[rx]
Constructional apraxia 0 The inability to draw, construct or copy simple configurations, such as intersecting shapes. These patients have difficulty copying a simple diagram or drawing basic shapes.^[7]
Gait apraxia – The loss of ability to have normal function of the lower limbs such as walking. This is not due to loss of motor or sensory functions.^[rx]
Ideational/conceptual apraxia – Patients cannot conceptualize a task and impaired ability to complete multistep actions. This form of apraxia consists of an inability to select and carry out an appropriate motor program. For example, the patient may complete actions in incorrect orders, such as buttering bread before putting it in the toaster or putting on shoes before putting on socks. There is also a loss of ability to voluntarily perform a learned task when given the necessary objects or tools. For instance, if given a screwdriver, the patient may try to write with it as if it were a pen, or try to comb their hair with a toothbrush.^[rx]^[rx]
Ideomotor apraxia – These patients have deficits in their ability to plan or complete motor actions that rely on semantic memory. They can explain how to act, but are unable to “imagine” or act out a movement such as “pretend to brush your teeth” or “pucker as though you bit into a sour lemon.” However, when the ability to activate automatically when cued remains intact, this is known as automatic-voluntary dissociation. For example, they may not be able to pick up a phone when asked to do so but can act without thinking when the phone rings.^[rx]^[rx]
Limb-kinetic apraxia – The inability to perform precise, voluntary movements of extremities. For example, a person affected by limb apraxia may have difficulty waving hello, tying their shoes, or typing on a computer.^[rx^] This type is common in patients who have experienced a stroke, some type of brain trauma, or have Alzheimer’s disease.^[rx]
Oculomotor apraxia 0 Difficulty moving the eye on command, especially with saccade movements that direct the gaze to targets. This is one of the 3 major components of Balint’s syndrome.^[rx]

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

Causes

Apraxia is caused by a defect in the brain pathways that contain a 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.

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.
Blepharospasm or focal dystonia of the eyelids – idiopathic (also known as benign essential blepharospasm), infectious (keratitis, blepharitis, dacryocystitis, conjunctivitis), toxic exposure (extensive sunlight), autoimmune (keratoconjunctivitis sicca from Sjogren’s disease), neurodegenerative (Parkinson’s and Huntington’s disease)
Face or eyebrow ptosis – severe levator palpebrae dysfunction from abnormal development, vascular injury, neuromuscular disease (myasthenia gravis), neuroimmunological (multiple sclerosis), trauma, iatrogenic (eye surgery). Ptosis can easily be corrected by tightening the muscle’s tendon that raises the eyelids.
Dermatochalasis – refers to excess upper or lower eyelid skin, or both. These are merely baggy eyelids and can be fixed by removing the excess baggage and skin in the eyelids.
Psychogenic– photophobia, fatigue

Several disorders will present like apraxia of eyelid opening and must be excluded to treat them appropriately.

Idiopathic
- Benign essential blepharospasm with or without sensory features including eye-burning pain, keratoconjunctivitis sicca, sensory trick, and photophobia[rx][rx]
- Meige’s syndrome: a triad of blepharospasm, oromandibular dystonia, and cervical dystonia
- Brueghel’s syndrome: blepharospasm, oromandibular dystonia, +/- torticollis, +/- dystonic writer’s cramp, appendicular dystonic posturing of the arms, dystonic respiration, and spasmodic torticollis[rx][rx]
Iatrogenic
- Drug-induced: associated with tardive dyskinesias with the use of mood stabilizers (antidepressants, antipsychotics, antiepileptics), antimicrobials, and antiarrhythmics[rx]
- Levodopa and apomorphine in progressive supranuclear palsy[rx]
- Deep brain stimulation on the subthalamic nucleus and the globus pallidus internus for Parkinson’s disease patients[rx][rx]
Genetic
- Primary blepharospasm and dystonias: can be accompanied by cervical dystonia. Torsion family 1 member A polymorphism with mutation on dystonia 1 protein,[rx][rx][rx] guanine nucleotide-binding protein,[rx] anoctamin 3,[rx] tubulin beta4A,[rx] and zinc finger protein 1[rx][rx]
Structural
- Vascular or traumatic injury of the midbrain, basal ganglia, thalamus, cerebellum, and motor cortex[rx]
- Hemifacial spasm: spasmodic unilateral facial contractions including eyelid blepharospasm due to facial nerve irritation
Neuroinflammatory
- Bell’s palsy: unilateral facial hemiparesis, constitutional symptoms (fever, chills), headaches, neck rigidity, retro auricular or jaw pain, hypersalivation, hyper acoustic phonophobia, dysgeusia, keratoconjunctivitis sicca
- Myasthenia gravis: oculomotor fatigue[rx][rx]
Neurodegenerative
- Parkinson’s disease[26][27]
- Focal, segmental, or generalized dystonia: uncontrolled hyperkinetic movements, including blepharospasm

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.

Related Disorders

The following disorder may be associated with Apraxia as a secondary characteristic. It is not necessary for a differential diagnosis:

Aphasia is a disturbance in the ability to comprehend or use language. It usually occurs as a result of injury to the language centers of the brain (cerebral cortex). Affected individuals may select the wrong words in conversing and may have problems interpreting verbal messages. Children born with Aphasia may not talk at all. 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.

Symptoms

The major symptom of Apraxia is a person’s inability to perform the movement in the absence of any physical paralysis. 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. Apraxia is sometimes accompanied by a person’s loss of ability to comprehend or use words (Aphasia).

Specific types of Apraxia are characterized by an inability to perform particular movements on command. For example, in Buccofacial Apraxia, an affected individual is unable to cough, whistle, lick one’s lips, or wink when asked. In Constructional Apraxia, an individual is unable to reproduce simple patterns or copy simple drawings.
Distorting sounds. People with AOS 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 AOS is accompanied by aphasia.
Making inconsistent errors in speech. For example, someone with AOS 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.
Groping for sounds. People with AOS often appear to be groping for the right sound or word and may try saying a word several times before they say it correctly.
Making errors in tone, stress, or rhythm. Another common characteristic of AOS is the incorrect use of prosody. Prosody is the rhythm and inflection of speech that we 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.

Diagnosis

History and Physical

Patients describe difficulty opening the eyes voluntarily and feeling persistent periorbital contractions. Most of the time, it occurs after the patient voluntarily closes their eyes. Patients show compensatory behaviors, which may include thrusting the head backward, manually opening the eyes with their fingers, and rubbing the eyebrows.

It is crucial to ascertain the historical progression of symptoms. A thorough past medical and ocular history may reveal risk factors associated with the condition. A focal ocular exam is essential, including visual acuity and field testing, ocular pressure testing, pupillary reflexes, extraocular movements, dilated fundoscopic examination, and slit-lamp examination. The examination can help narrow the etiology of the symptoms.

An external evaluation of the eyelids and facial muscles is essential to assess eyebrow and eyelid ptosis, dermatochalasis, and spasms of the orbicularis oculi, procerus, and corrugator muscles. Assessing mental status, language skills, and other cranial exams may be useful if central causes are suspected.

This condition is a clinical diagnosis; therefore, a thorough medical history and physical, ocular history, and focused visual exam are essential. Historical inquiry of progression and risk factors can narrow the differential. There have been clinical criteria established by Defazio and Berardelli for the identification of clinical and physical exam phenomenology, with validation from expert neurologists and neuro-ophthalmologists.[5] These include orbicularis oculi involuntary spastic eyelid narrowing/closure, bilateral laterality, synchronous spasm frequency, stereotypical spasm pattern, alleviation with a sensory trick, inability to suppress spasms, and high-frequency blink count at rest. A combination of them had a 93% sensitivity and 90% specificity for blepharospasm. A focal physical and ocular exam can help identify and confirm the clinical diagnosis.

If a central nervous system cause is suspected, a head computed tomographic (CT) scan or brain magnetic resonance imaging (MRI) with and without contrast is performed.

Extensive serum laboratories and cerebrospinal fluid analysis, including systemic immune, autoimmune, and infectious causes, may be useful to exclude secondary causes of blepharospasm.

Treatment

Treatment for individuals with apraxia includes speech therapy, occupational therapy, and physical therapy. Currently, there are no medications indicated for the treatment of apraxia, only therapy treatments. 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.

Children with AOS 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 AOS as well as for people with acquired AOS who do not spontaneously recover all of their speech abilities.

Speech-language pathologists use different approaches to treat AOS, 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 AOS. Frequent, intensive, one-on-one speech-language therapy sessions are needed for both children and adults with AOS. (The repetitive exercises and personal attention needed to improve AOS are difficult to deliver in group therapy.) Children with severe AOS 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 AOS 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 AOS learn to read and better understand spoken language by stimulating areas of the brain involved in language and literacy.

For refractory cases, myectomy with tightening of the levator tendon that elevates the eyelids (also called aponeurotic ptosis repair) and blepharoplasty can be considered. Myectomy of fibers of orbicular muscle in the central portion of the eyelid can be performed if botulinum toxin does not produce good results. Frontalis suspension is performed as a last resort, by placing a suture between the forehead muscle and the eyelids.

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