Movement Disorders

Overview

From raising a hand to laughing, every physical movement includes a complicated interplay between the central nervous system (brain and spinal cord), nerves, and muscles. Any of these components that is damaged or malfunctioning may cause a movement issue.

Movement disorders are neurological diseases that result in erratic movements. It is estimated that 42 million people in the United States suffer from some sort of movement problem.

 

What are Movement Disorders?

Parkinson disease (PD), tremor, tics, and dystonia are clinically, pathologically, and genetically diverse movement diseases defined by impairment in movement planning, control, or execution.

First and foremost, the right classification of the kind of movement disorder serves as the foundation for the ensuing diagnostic procedure. Most illnesses lack a particular biological signature that may reliably diagnose the underlying condition. Many diagnostic tests are available, but they are frequently costly, time-consuming, and, in some cases, intrusive. Furthermore, the diagnostic utility of these tests is frequently restricted, particularly in the early stages of the disease.

Because of the wide variety of probable diagnoses, hiding clinical uncertainty behind a comprehensive battery of ancillary investigations is often unrewarding. Once the kind of movement disorder has been accurately recognized, the exploratory work-up may be substantially streamlined since the approach to each type of movement disorder becomes more concentrated.

 

Ataxia

Ataxia is a neurological condition characterized by a loss of coordination in the action of various muscles throughout the body. It is a clinical finding, not a disease, characterized by gait abnormalities, speech changes such as scanning speech, and abnormal eye movements such as nystagmus. It is caused by a malfunction of the brain regions involved for movement coordination, most often the cerebellum. Ataxia is classified into three kinds based on its location: cerebellar, sensory, and vestibular.

Ataxia is further classified as 

• Sporadic (no family history of ataxia and developing in maturity), 
• Hereditary (caused by a gene abnormality and manifesting in childhood), and 
• Acquired (due to structural or demyelinating conditions, toxicity, paraneoplastic, inflammatory or infections, and autoimmune conditions). 

Friedreich ataxia is the most prevalent genetic type of ataxia and is autosomal recessive.

 

Ataxia causes

Ataxia can be caused by abnormalities in various areas of the nervous system, including the brain, spinal cord, nerves, and nerve roots. In the same patient, several kinds of ataxia might have similar or overlapping origins.

• Focal lesions - due to tumors, stroke, multiple sclerosis, or inflammation
• Metabolic - due to substances such as alcohol, antidepressant drugs, and antiepileptic drugs
• Poisoning - due to radiation
• Vitamin B12 deficiency
• Thyroid disease - Hypothyroidism
• Head injury
• Coeliac disease (gluten ataxia)
• Hereditary 

 

Ataxia symptoms  

A thorough history and examination are essential in evaluating, determining the site of the lesion, and treating individuals with ataxia. Age, gender, neurological, pharmacological, toxin, and occupational exposures should all be included in the medical history. Family history is critical. The existence of constitutional symptoms such as fever, weight loss, and night sweats should be assessed during the systems evaluation. A history of diabetes, hypertension and neurological disorders is required.

Clinicians should question patients if any of the symptoms and indicators are present, as well as their level of functional handicap in daily activities, start, and progression. Abnormalities in gait, slurred speech, trouble walking, irregular eye movements, difficulty eating, increased tiredness, incoordination in fine motor activities such as handwriting, buttoning shirts, typing, tremors, vertigo, and cognitive impairments are common indications and symptoms.

 

Ataxia diagnosis

Clinical presentation and clinical suspicion guide the necessary tests. Blood tests for deficiencies, drugs, and toxins may be required. Urinalysis can be used to detect mercury levels.

A computed tomographic scan is used as the first investigation in brain imaging, but MRI is required to reveal structural lesions, strokes, and congenital or acquired abnormalities. If a spine lesion is suspected, MRI imaging of the spinal cord is recommended.

 

Ataxia Treatment 

There is currently no curative therapy for inherited ataxia. If the ataxia is caused by a stroke, toxic chemicals, hypothyroidism, or other modifiable risk factors, therapy is directed on the specific condition causing the ataxia. Some curable reasons, such as vitamin E deficiency, coenzyme Q10 deficiency, and episodic ataxia type two, are reversible with medicine.

Patients may utilize walking aids, canes, wheelchairs, and walkers to lessen functional impairment. Physical, verbal, and symptomatic treatments are available to patients. Tremors, muscular stiffness, and sleeping difficulties can all be treated with medication. Physical and mental workouts have been shown to enhance the lives of persons with ataxia.

 

Dystonia

Dystonia is characterized by involuntary sustained contraction of agonist and antagonist muscles, resulting in aberrant posture, twisting, and repetitive motions, or tremulousness, and can be triggered or exacerbated by attempted movement.

Dystonia is a dynamic condition whose severity varies depending on activities and posture. Dystonia can manifest as overextension or overflexion of the hand, foot inversion, lateral flexion or retroflexion of the head, torsion of the spine with arching and twisting of the back, forced closing of the eyelids, or a permanent grimace. It may come to an end when the body is in motion or while sleeping.

Dystonia can range from mild to severe, with noticeable swings in individual patients. Severe instances are characterized by ugly and twisted motions. The level of severity varies.

Because of its varied course and widespread manifestation, it is commonly misdiagnosed. People with dystonia can usually lead quite normal lives, while others require support with all daily tasks.

 

Dystonia Causes

Dystonia is a complex condition with several etiologies and clinical manifestations. One of the most helpful dystonia classifications is by etiology: primary and secondary dystonia.

Dytonia is the only neurologic symptom in primary dystonia (familial or sporadic, also known as idiopathic torsion dystonia), when other causes of dystonia, such as acquired or neurodegenerative diseases, have been ruled out. Even in the absence of a family history of dystonia, primary dystonia is regarded to have a stronger genetic influence. Primary dystonia's exact etiology is unknown. There is some hereditary predisposition, as well as environmental variables.

Secondary dystonias are brought on by an environmental insult and are brought on by some known causes, such as head injury, pharmacological side effects (e.g., tardive dyskinesia), or neurological illness (e.g., Wilson disease).

 

Dystonia Symptoms

It is critical to differentiate between idiopathic and symptomatic dystonia. Idiopathic dystonia can be hereditary, has a slow beginning, and appears first during the performance of a certain, repeated, well-learned activity. Symptomatic (secondary) dystonia, on the other hand, comes as a result of a stroke, tumor, infection, hypoxia-ischemia, encephalitis, neurodegenerative illness (e.g., hepato-lenticular degeneration or Wilson's disease), or toxins.

In dystonia, the clinical examination may reveal involuntary writhing/twisting motions triggered by particular voluntary activities such as walking or writing. When writing, focal task-specific limb dystonia might manifest as painful hand cramping or involuntary wrist/finger spasms, whereas torticollis manifests as an uncontrolled head-turning when driving or watching television.

• Oro-mandibular dystonia can appear as nighttime bruxism (jaw spasms resulting in forced jaw closure) and can occur as a result of dental treatments, oro-mandibular-facial trauma, or temporomandibular joint dysfunction.
• Spasmodic dysphonia might start with a strained voice. Despite the term, the tone of afflicted limbs at rest is generally normal at the start of dystonia. Deep tendon reflexes are also possible.
• A tremor in a dystonia patient (dystonic tremor) can be recognized from other tremor types by the existence of a null point (e.g., a neutral position at which the tremor attenuates).
• Head tremor in cervical dystonia occasionally diminishes when the head is maintained in a certain posture, and movement away from that position, such as moving the head to one side, may aggravate it.
• Dystonic tremor is characterized by nonuniform amplitude and frequency, is associated with myoclonus (jerk-like motions), and fades during sleep. In spasmodic torticollis, dystonia can produce hypertrophy and discomfort in afflicted muscles such as the sternocleidomastoid.

 

Dystonia Diagnosis

The kind of dystonia is used to determine examination and treatment, with clinical presentation remaining the most important factor. Clinical assessment and genetic testing can aid in the diagnosis of primary dystonia.

Secondary dystonia is defined as a condition that arises as a result of environmental influences that impact the brain, particularly the basal ganglia. Dystonia can also be caused by spinal cord or peripheral nerve damage. So, a history of possible head trauma, encephalitis, toxin and drug exposure, perinatal anoxia, as well as the presence of neurologic abnormality apart from dystonia, such as Parkinsonism, dementia, seizures, ocular symptoms, ataxia, neuropathy, spasticity, with abnormal brain imaging, will help to guide the diagnosis of secondary dystonia.

Because many neurodegenerations are caused by genetic defects, this group is known as Heredodegenerative dystonia. Dystonia is a significant characteristic of Neurodegeneration. A few examinations worth noting include MRI of the brain, ceruloplasmin level, slit-lamp exam, lysosomal screen, peripheral blood smear, nerve conduction tests, creatine kinase (CK) level, and vitamin E. Imaging tests can detect central lesions, bleeding, and hypoxic damage.

 

Dystonia Treatment

Anticholinergics (trihexyphenidyl), GABA agonists (baclofen and benzodiazepines), and dopaminergic medicines are the most effective treatments for dystonia. These medications work by altering dopaminergic and cholinergic neurotransmission and decreasing GABA-mediated inhibition in the dystonic central nervous system (CNS)

Trihexyphenidyl is the first-line drug for the treatment of primary generalized or segmental dystonia in children. Botulinum toxin injections can successfully cure focal dystonia. The toxin inhibits the vesicular release of acetylcholine into the neuromuscular junction, resulting in brief local chemo-denervation and muscle weakening, as well as a reduction in the excessive activity of the afflicted dystonic muscles.

Botulinum toxin is the first-line therapy for cervical dystonia and blepharospasm, as well as laryngeal dystonia (spasmodic dysphonia) and focal limb dystonia. Botulinum toxin injections may diminish afferent signals from damaged muscles, potentially restoring the aberrant plastic changes in the CNS, in addition to their immediate peripheral action of weakening affected muscles.

 

Huntington's Disease

Huntington's disease (HD), a neurological autosomal dominant condition, is characterized by involuntary choreatic movements as well as cognitive and behavioral problems. It is caused by cytosine, adenine, and guanine (CAG) trinucleotide repeats in the Huntingtin (HTT) gene on the short arm of chromosome 4p16.3. This mutation causes an excessively lengthy polyglutamine expansion in the HTT protein, resulting in neurodegeneration.

The enlargement also makes the HTT protein more susceptible to aggregation and accumulation, which reduces protein folding. HD most typically affects adults between the ages of 30 and 50. The longer the CAG repetitions, however, the sooner the development of symptoms. Juvenile HD is defined as the start of sickness before the age of 20 and is marked by learning problems as well as behavioral disorders at school.

 

Huntington disease Causes

Huntington's disease is an autosomal dominant illness caused by the extension of CAG repeats in the HTT gene on the short arm of chromosome 4p16.3. The gene encodes the HTT protein, which is involved in synaptic function and is also important in the post-embryonic stage. It is considered to have anti-apoptotic properties as well as the ability to defend against the toxic mutation HTT.

Some data suggests that the mutant protein causes both an addition and a loss of function. Several parts of the brain include intranuclear and intracytoplasmic inclusions. It is uncertain, however, whether the inclusions themselves play a role in the pathogenesis or are harmful in and of themselves. It is generally known that brain atrophy, particularly in the striatum, is accompanied with substantial neuronal loss.

 

Huntington disease Symptoms 

Patients between the ages of 30 and 50 are most commonly affected by the condition. Motor, cognitive, and mental problems are common indications and symptoms. Weight loss, sleep problems, and autonomic nervous system dysfunction are some of the less frequent symptoms.

• Motor disturbances: 

These include the typical undesired involuntary movements that originate in the distal extremities and are of a lesser degree but can impact the face muscles as well. The motions then gradually extend to the more proximal and axial muscles, becoming larger in amplitude. Motor complaints are usually progressive. 

The balance of chorea and hypokinesia varies from patient to patient and ranges from overwhelming rigidity in younger patients, also known as the Westphal variant, to older patients who are severely affected in the later stages of the disease with rigidity and contractures in the extremities, causing them to be bedridden. During the course of the disease, dysarthria and dysphagia develop, which can lead to aspiration in patients, with pneumonia being a major cause of death.

Dystonia, which is characterized by increased muscle tone and slower movements, causes aberrant posture such as torticollis and is the earliest evidence of motor involvement in HD. Tics and cerebellar symptoms such as ataxia are examples of involuntary characteristics. There are pyramidal signs, such as the Babinski sign. The motor disturbance in daily tasks worsens over time, resulting in difficulty walking, standing, and frequent falls.

• Behavioral and psychiatric symptoms: 

These appear relatively early in the illness, typically before motor symptoms appear. Frontal lobe impairment is frequently associated with behavioral and psychiatric disorders. Patients may first exhibit poor concentration, impulsivity, and impatience. The irritation is frequently intense, resulting in outbursts of wrath and hostility. Later in the disease, there is emotional blandness, apathy, lack of intuition, and inventiveness.

Psychosis might develop later in the disease's progression, sometimes in conjunction with cognitive deterioration. Another notable trait is a lack of understanding about the nature of the symptoms they are experiencing. This involves a dearth of knowledge about all three aspects of the condition (motor, cognitive, and psychiatric). As a result, family members become an important source of knowledge and should be included in decision-making and evaluation.

• Cognitive disturbances:

One of the key characteristics of HD is cognitive decline, which may occur prior to the start of motor problems. Executive functions are more affected by cognitive alterations, with patients having trouble organizing, multitasking, and planning. These symptoms escalate to further cognitive abnormalities, eventually leading to dementia.

Dementia in HD is subcortical in nature, with memory loss resulting from an inefficient search for memory rather than a poor memory, and characteristics such as apraxia and aphasia, which are typical in cortical dementia, are avoided in HD. Psychomotor functions are greatly slowed.

 

Huntington disease diagnosis

Once the patient has been diagnosed with HD, he or she will experience both short-term and long-term reactions to living with the condition. Prior to providing the diagnosis, it is critical to recognize the status of the psychological reaction. In a subset of patients, psychological preparation lags behind symptomatology, potentially leading to serious adverse outcomes. As a result, recognizing the phases gives a framework for assessing their mental state and deciding their willingness to receive the diagnoses.

The diagnosis is based on clinical indications and symptoms in a patient who has a verified HD parent. The existence of motor symptoms, with or without mental or cognitive abnormalities, or generally a mix of all three, in the context of positive family history, is usually enough to make a diagnosis. The order of the physical, psychological, and cognitive disorders is vary, which can lead to a delay or misdiagnosis.

Prior to genetic testing, basic investigations should be carried out. Lab testing is very important in distinguishing HD from other progressive inherited HD-like disorders. Creatine kinase and liver enzyme levels are typically elevated in chorea-acanthocytosis and McLeod syndrome. Lipoprotein electrophoresis may be abnormal in patients with pantothenate kinase-associated neurodegeneration.

Magnetic resonance imaging (MRI) can help in diagnosis. MRI data are apparent before overt clinical manifestation; changes in brain volume and brain connectivity occur several years before clinical manifestation. Adult-onset HD is often characterized by caudate striatal atrophy.

Later in the illness, cerebellar and cortical atrophy is seen. MRI is useful in distinguishing HD from other types of spinocerebellar ataxia and in distinguishing juvenile HD from other metal accumulation illnesses such as Wilson's disease and aceruloplasminemia. However, MRI results are indistinguishable across numerous progressive HD-like disorders. Both chorea-acanthocytosis and McLeod's syndrome are characterized by caudate atrophy and dilatation of the anterior horns of the lateral ventricle.

 

Huntington disease Treatment 

There is no treatment for HD. However, there are several treatment choices for addressing signs and symptoms with the goal of enhancing quality of life. The treatment consists mostly of pharmaceutical as well as supportive measures. Surgical treatment has no significant function. Many pharmaceutical and surgical methods for chorea suppression have been studied, including dopamine antagonists, benzodiazepines, acetylcholinesterase inhibitors, lithium, deep brain stimulation, and glutamate antagonists.

 

Parkinson's Disease

Parkinson's disease is a degenerative ailment caused by nerve cell degeneration in the substantia nigra, a region of the brain that governs movement. These nerve cells die or become damaged, reducing the capacity to create dopamine, an essential neurotransmitter.

Parkinson's produces many common symptoms, including: 

• Tremor; 
• Muscle rigidity or stiffness of the limbs; 
• Gradual loss of spontaneous movement, often leading to decreased mental skill or reaction time, 
• Gradual loss of automatic movement, often leading to decreased blinking, 
• Voice changes or decreased facial expression;
• Depression or dementia
• Decreased frequency of swallowing, and
• Drooling; a stooped, flexed posture, with bending at the elbows, knees and hips; an unsteady walk or balance; and

According to the Parkinson's Disease Foundation, 60,000 new cases of Parkinson's condition are identified each year, adding to the seven to ten million individuals worldwide who have the disease. While the chance of developing Parkinson's disease grows with age, only 4% of individuals affected are diagnosed before the age of 50.

Most Parkinson's sufferers are given drugs to alleviate their symptoms. Dopamine precursors, dopamine agonists, and anticholinergics are some of the most often used drugs. When drugs have proven ineffectual, surgery is considered.

Deep Brain Stimulation (DBS) of the subthalamic nucleus or globus pallidus can be helpful in treating all of the basic motor symptoms of Parkinson's disease and can occasionally result in large reductions in medication dosages. Thalamotomy, which involves implanting a tiny lesion in a particular nucleus of the thalamus, can assist to alleviate tremor. 

 

Essential Tremor

Essential tremor is characterized by uncontrollable shaking or trembling of one or both hands or arms, which intensifies when simple motions are tried. Essential tremor affects around five million persons in the United States; essential tremors are most frequent in adults over the age of 65. It is caused by anomalies in brain regions that govern movement and is unrelated to an underlying condition (e.g., Parkinson's disease)

About half of the patients have a family history of the disease. This illness seldom causes major consequences, although it may certainly interfere with everyday tasks and cause distress.

Physical therapy or a change in lifestyle may help alleviate symptoms in certain circumstances. If a patient's ability to conduct everyday duties is impaired and their quality of life suffers, medication or surgery may be explored. Tremor is reduced in 50 to 75 percent of individuals who use medicines.

Anti-seizure drugs, beta-blockers, benzodiazepines, and carbonic anhydrase inhibitors are frequently recommended. Because beta-blockers can induce memory loss and disorientation in older people, they are often given for younger patients. Botox injections serve to disrupt nerve-muscle transmission, which may reduce tremor.

Surgery may be suggested if the tremor is severe enough to cause impairment. Thalamotomy is the deliberate destruction of a piece of the thalamus, a deep within the brain location that receives sensory impulses. Approximately 75% of people who have this treatment receive alleviation on one side of their body.

Due to the considerable risk of speech loss, surgery on both sides of the thalamus is seldom performed. In severe cases of essential tremor that have not responded to treatment, Deep Brain Stimulation is another surgical option. A hair-thin wire is inserted into the thalamus and linked to a neurostimulator inserted behind the collarbone. The neurostimulator transmits electrical impulses up the wire to the thalamus, disrupting tremor-causing signals.

 

Spasticity

Spasticity is defined as increased muscular contractions that cause muscle stiffness or tightness, which can impair with movement, speaking, and walking. Spasticity is typically caused by injury to the area of the brain or spinal cord that regulates voluntary movement. It can be caused by spinal cord injury, multiple sclerosis, cerebral palsy, stroke, brain damage caused by oxygen deprivation, severe head injury, and metabolic illnesses such as Lou Gehrig's disease (ALS).

Medications such as baclofen, diazepam, tizanidine, and clonazepam may be used in treatment. In order to assist minimize the intensity of symptoms, physical therapy with particular muscle exercises may be given. Surgery may be advised to release a tendon or to sever the nerve-muscle pathway. 

 

Conclusion 

Movement disorders are a set of hypokinetic and hyperkinetic neurologic conditions defined by impaired basal ganglia activity. Each of these illnesses has a unique appearance and natural history in terms of age of start, anatomic distribution, and severity. Even in the hands of seasoned movement disorder specialists, determining an accurate diagnosis can be challenging. However, precise identification based on clinical acumen is critical for a variety of reasons.