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Surgery, such as the denervation of selected muscles, may also provide some relief; however, the destruction of nerves in the limbs or brain is not reversible and should be considered only in the most extreme cases. Recently, the procedure of deep brain stimulation (DBS) has proven successful in a number of cases of severe generalised dystonia. DBS as treatment for medication-refractory dystonia, on the other hand, may increase the risk of suicide in patients. However, reference data of patients without DBS therapy are lacking.
An occurrence of Todd's paralysis indicates that a seizure has occurred. The prognosis for the patient depends upon the effects of the seizure, not the occurrence of the paralysis.
The cause of Todd's paresis been attributed to the affected cortex being ‘exhausted’ or silenced due to increased inhibition, but these conjectures are not supported. It has been observed that the impairments that follow seizures are similar to those that follow strokes, where for a period of time blood flow to certain areas of the brain is restricted and these areas are starved of oxygen.
Paroxysmal Dyskinesia is not a fatal disease. Life can be extremely difficult with this disease depending on the severity. The prognosis of PD is extremely difficult to determine because the disease varies from person to person. The attacks for PKD can be reduced and managed with proper anticonvulsants, but there is no particular end in sight for any of the PD diseases. PKD has been described to cease for some patients after the age of 20, and two patients have reported to have a family history of the disease where PKD went into complete remission after the age of 23. With PNKD and PED, at this time, there is no proper way to determine an accurate prognosis.
All PD associated subtypes have genetic contributions and are likely to run in a families genetic history due to dominant allele mutations. Mutations of identified genes have been leading areas of research in the study and treatment of paroxysmal dyskinesia. PKD, PNKD, and PED are classified as separate subtypes because they all have different presentations of symptoms, but also, because they are believed to have different pathologies.
Interestingly, studies on diseases that are similar in nature to PD have revealed insights into the causes of movement disorders. Hypnogenic paroxysmal dyskinesia is a form of epilepsy affecting the frontal lobe. Single genes have been identified on chromosomes 15, 20, and 21, which contribute to the pathology of these epilepsy disorders. Utilizing new knowledge about pathologies of related and similar disease can shed insight on the causal relationships in paroxysmal dyskinesia.
Drugs that can trigger an oculogyric crisis include neuroleptics (such as haloperidol, chlorpromazine, fluphenazine, olanzapine), carbamazepine, chloroquine, cisplatin, diazoxide, levodopa, lithium, metoclopramide, lurasidone, domperidone, nifedipine, pemoline, phencyclidine ("PCP"), reserpine, and cetirizine, an antihistamine. High-potency neuroleptics are probably the most common cause in the clinical setting.
Other causes can include postencephalitic Parkinson's, Tourette's syndrome, multiple sclerosis, neurosyphilis, head trauma, bilateral thalamic infarction, lesions of the fourth ventricle, cystic glioma of the third ventricle, herpes encephalitis, kernicterus and juvenile Parkinson's.
Patients who develop PSH after traumatic injury have longer hospitalization and longer durations in intensive care in cases where ICU treatment is necessary. Patients often are more vulnerable to infections and spend longer times on ventilators, which can lead to an increased risk of various lung diseases. PSH does not affect mortality rate, but it increases the amount of time it takes a patient to recover from injury, compared to patients with similar injuries who do not develop PSH episodes. It often takes patients who develop PSH longer to reach similar levels of the brain activity seen in patients who do not develop PSH, although PSH patients do eventually reach these same levels.
Pisa syndrome is predominantly caused by a prolonged administration or an overly dosed administration of antipsychotic drugs. Although antipsychotic drugs are known to be the main drugs that are concerned with this syndrome, several other drugs are reported to have caused the syndrome as well. Certain antidepressants, psychoactive drugs, and antiemetics have also been found to cause Pisa syndrome in patients.
Drugs found to have caused Pisa Syndrome:
- Atypical antipsychotic drugs- ex. clozapine, aripiprazole
- Tricyclic antidepressants- ex. clomipramine
- Psychoactive drugs
- Antiemetic drugs
- Cholinesterase inhibitors
- Galantamine
Based on the drugs that caused Pisa syndrome, it has been implicated that the syndrome may be due to a dopaminergic-cholinergic imbalance or a serotonergic or noradrenergic dysfunction. For the development of Pisa syndrome that cannot be alleviated by anticholinergic drugs, it has been considered that asymmetric brain functions or neural transmission may be the underlying mechanism. How these drugs interact with the biochemistry of the brain to cause the syndrome is unknown and a topic of current research.
Paroxysmal kinesigenic choreathetosis (PKC) also called paroxysmal kinesigenic dyskinesia (PKD) is a hyperkinetic movement disorder characterized by attacks of involuntary movements, which are triggered by sudden voluntary movements. The number of attacks can increase during puberty and decrease in a person's 20s to 30s. Involuntary movements can take many forms such as ballism, chorea or dystonia and usually only affect one side of the body or one limb in particular. This rare disorder only affects about 1 in 150,000 people with PKD accounting for 86.8% of all the types of paroxysmal dyskinesias and occurs more often in males than females. There are two types of PKD, primary and secondary. Primary PKD can be further broken down into familial and sporadic. Familial PKD, which means the individual has a family history of the disorder, is more common, but sporadic cases are also seen. Secondary PKD can be caused by many other medical conditions such as multiple sclerosis (MS), stroke, pseudohypoparathyroidism, hypocalcemia, hypoglycemia, hyperglycemia, central nervous system trauma, or peripheral nervous system trauma. PKD has also been linked with infantile convulsions and choreoathetosis (ICCA) syndrome, in which patients have afebrile seizures during infancy (benign familial infantile epilepsy) and then develop paroxysmal choreoathetosis later in life. This phenomenon is actually quite common, with about 42% of individuals with PKD reporting a history of afebrile seizures as a child.
Anticholinergic drugs have been reported to be extremely effective in 40% of the patients with the Pisa syndrome. Patients with Pisa syndrome that is resistant to anticholinergic drugs is mostly resolved by the reduction of the administration of the antipsychotic drugs as previously mentioned. While the specific pathology underlying idiopathic Pisa syndrome is unknown, the administration of anticholinergic drugs has provided resolution in known cases.
Epilepsy is a relatively common disorder, affecting between 0.5-1% of the population, and frontal lobe epilepsy accounts for about 1-2% of all epilepsies. The most common subdivision of epilepsy is symptomatic partial epilepsy, which causes simple partial seizures, and can be further divided into temporal and frontal lobe epilepsy. Although the exact number of cases of frontal lobe epilepsy is not currently known, it is known that FLE is the less common type of partial epilepsy, accounting for 20-30% of operative procedures involving intractable epilepsy. The disorder also has no gender or age bias, affecting males and females of all ages. In a recent study, the mean subject age with frontal lobe epilepsy was 28.5 years old, and the average age of epilepsy onset for left frontal epilepsy was 9.3 years old whereas for right frontal epilepsy it was 11.1 years old.
Oculogyric crisis (OGC) is the name of a dystonic reaction to certain drugs or medical conditions characterized by a prolonged involuntary upward deviation of the eyes. The term "oculogyric" refers to the bilateral elevation of the visual gaze, but several other responses are associated with the crisis.
Epilepsy can manifest as oculogyric seizures, also called versive seizures.
Spasmodic torticollis is one of the most common forms of dystonia seen in neurology clinics, occurring in approximately 0.390% of the United States population in 2007 (390 per 100,000). Worldwide, it has been reported that the incidence rate of spasmodic torticollis is at least 1.2 per 100,000 person years, and a prevalence rate of 57 per 1 million.
The exact prevalence of the disorder is not known; several family and population studies show that as many as 25% of cervical dystonia patients have relatives that are undiagnosed. Studies have shown that spasmodic torticollis is not diagnosed immediately; many patients are diagnosed well after a year of seeking medical attention. A survey of 59 patients diagnosed with spasmodic torticollis show that 43% of the patients visited at least four physicians before the diagnosis was made.
There is a higher prevalence of spasmodic torticollis in females; females are 1.5 times more likely to develop spasmodic torticollis than males. The prevalence rate of spasmodic torticollis also increases with age, most patients show symptoms from ages 50–69. The average onset age of spasmodic torticollis is 41.
Paroxysmal kinesigenic dyskinesia has been shown to be inherited in an autosomal dominant fashion. In 2011, the PRRT2 gene on chromosome 16 was identified as the cause of the disease. The researchers looked at the genetics of eight families with strong histories of PKD. They employed whole genome sequencing, along with Sanger sequencing to identify the gene that was mutated in these families. The mutations in this gene included a nonsense mutation identified in the genome of one family and an insertion mutation identified in the genome of another family. The researchers then confirmed this gene as the cause of PKD when it was not mutated in the genome of 1000 control patients. Researchers found PRRT2 mutations in 10 of 29 sporadic cases affected with PKD, thus suggests PRRT2 is the gene mutated in a subset of PKD and PKD is genetically heterogeneous. The mechanism of how PRRT2 causes PKD still requires further investigation. However, researchers suggest it may have to do with PRRT2's expression in the basal ganglia, and the expression of an associated protein, SNAP25, in the basal ganglia as well.
The number of events that can lead to the development of PSH symptoms is many. The exact pathways or causes for the development of the syndrome are not known. Traumatic brain injury, hypoxia, stroke, anti-NMDA receptor encephalitis (although further associations are being explored), injury of the spinal cord, and many other forms of brain injury can cause onset of PSH. Even more obscure diseases such as intracranial tuberculoma have been seen to cause onset of paroxysmal sympathetic hyperactivity. It is observed that these injuries lead to the development of PSH or are seen in conjunction with PSH, but the pathophysiology behind these diseases and the syndrome is not well understood.
When other conditions lead to spasmodic torticollis, it is said that the spasmodic torticollis is secondary. A variety of conditions can cause brain injury, from external factors to diseases. These conditions are listed below:
- Perinatal (during birth) cerebral injury
- Kernicterus
- Cerebrovascular diseases
- Drug induced
- Central nervous system tumor
- Peripheral or central trauma
- Infectious or post infectious encephalopathies
- Toxins
- Metabolic
- Paraneoplastic syndromes
- Central pontine myelinolysis
Secondary spasmodic torticollis is diagnosed when any of the following are present: history of exogenous insult or exposure, neurological abnormalities other than dystonia, abnormalities on brain imaging, particularly in the basal ganglia.
There is a group called myoclonic dystonia where some cases are hereditary and have been associated with a missense mutation in the dopamine-D2 receptor. Some of these cases have responded well to alcohol.
Other genes that have been associated with dystonia include CIZ1, GNAL, ATP1A3, and PRRT2. Another report has linked THAP1 and SLC20A2 to dystonia.
Two other types, primary ciliary dyskinesia and biliary dyskinesia, are caused by specific kinds of ineffective movement of the body, and are not movement disorders.
Spastic thrusting of hip area can occur in Sodemytopic Parkinson's.
Epilepsy has a substantial impact on the quality of life of the individuals that are afflicted with it. Physicians and researchers are coming to understand that the impact on the quality of life of the patient is as important as the effects of the seizures. Quality of life questionnaires and other assessment tools have been created to help quantify quality of life for individual patients. They consider such factors as physical health (including numbers and severity of seizures, medication side effects etc.), mental health, social relationships, lifestyle, role activities and life fulfillment. A Center for Disease Control study reported that seizure sufferers were more likely to have lower education levels, higher unemployment, higher levels of pain, hypersomnia/insomnia, increased psychological distress and social isolation/connection issues. Some of the issues which impact quality of life for people with epilepsy are: ability to drive and travel, the ability to date, marry and have children, the ability to have a job and independence, the ability to have an education and learn, and the ability to have good health and mental functioning. Future research is needed to find ways of not only controlling frontal lobe seizures, but of also addressing the specific quality-of-life issues that plague those with frontal lobe epilepsy.
- Driving and transportation restrictions
- Driving and travel restrictions are one of the greatest limitations that epileptic patients experience. Laws restricting driving privileges vary greatly in the United States as well as across the world. In the United States, 28 states require a patient to be seizure free for fixed periods of time ranging from 3–12 months. However, research done by Johns Hopkins University showed that there was no difference in seizure-related fatal crash rates in states with 3-month restrictions versus states with 6-12 month seizure-free restrictions. In 23 states, the restrictions and seizure free periods vary depending on the type of epilepsy and the individual case and in 13 states physicians were responsible for determining whether their patients should be allowed to drive. In 6 of those 13 states physicians could be held legally liable for their decisions regarding their epileptic patients’ driving capabilities. In many states, patients can also be legally liable for accidents, injury, damage and death caused by seizure related accidents.
- One of the major arguments in favor of restricting the licensing of epileptic drivers is the concern for public safety. However, the Johns Hopkins study showed that in a particular 2 year timeframe only 0.2% of fatal crashes occurred as a result of seizures. Alcohol related crash fatalities caused 156 times more driver deaths than seizure related crashes and young drivers between the ages of 16 and 24 were 123 times more likely to die in a fatal crash caused by their inexperience than an epileptic driver was to die in a crash that resulted from a seizure.
- Frontal lobe epileptic seizures unlike other epileptic seizures create symptoms that are as dangerous as loss of consciousness and much more difficult to discern from other problems such as drug and alcohol abuse, psychiatric disorders and disobedience. Jerking movements/lack of motor control, pedaling, pelvic thrusting, lapses in cognitive functioning and other hallmark symptoms of frontal lobe epileptic seizures all create dangerous behavior behind the wheel. Studies have not been done to date to determine the differential risk posed by drivers with frontal lobe epilepsy relative to the general epileptic population.
- Hormones and pregnancy issues
- Hormonal changes and pregnancy can shift seizure activity and the use of antiepileptic drugs can alter the efficacy of hormones as well as cause congenital malformations in fetuses. Seizure control in pregnant women is very important to the welfare of both the developing fetus and the mother. Hormonal shifts at puberty, with birth control and at menopause can also cause changes in the frequency and severity of seizures and must be closely monitored. Increased seizure activity is reported by 50% of women during the course of the pregnancy due to changing levels of hormones, fluids, salts and absorption and elimination of medications.
- Employment
- A report by the Epilepsy Foundation noted that the unemployment rate amongst people with epilepsy is 25% and in patients whose seizures are poorly controlled the rate jumps to 50%. Even though people with epilepsy are protected under The Americans with Disabilities Act, employment discrimination and high rates of unemployment due to employer attitudes still exist. A study in the UK showed that 16% of employers surveyed felt there were no jobs in their company suitable for people with epilepsy and that 21% felt that employing an epileptic would be a “major issue”. Fifty percent of the employers said they had a high concern regarding employing people with epilepsy with most citing safety concerns/workplace accidents as their major issue. Patients with frontal lobe epilepsy may be particularly prone to being discriminated against in employment and subject to higher rates of termination due to the unusual motor symptoms, speech, vocal outbursts and cognitive/judgment symptoms displayed during frontal lobe seizures. Frontal lobe seizures also tend to come on suddenly and progress rapidly making it difficult for an employer to control the exposure of the seizure to others.
- Education, learning and cognitive function
- Patients with frontal lobe epilepsy will likely also experience issues with learning and education. Many factors contribute to these issues including the impact of anticonvulsant medications. Anticonvulsant medications cause patients to feel “foggy” and sluggish. Drugs such as Topiramate cause problems such as mental blunting, word retrieval difficulties and irritability. Phenobarbital, Primidone and Vigabatrin can cause depression and suicidal tendencies. Stress and lack of sleep during exam periods can trigger seizures and many school sports teams restrict or ban people with epilepsy from sports for safety and liability reasons. Frontal lobe epilepsy sufferers also exhibit dysfunctional cognitive skills and memory issues which can make learning challenging. Research has shown that frontal lobe epilepsy has a greater negative impact than other forms of epilepsy on cognitive functioning. People with frontal lobe epilepsy show decreased cognitive capabilities in the following areas: humor appreciation, recognition of emotional expressions, response selection/initiation and inhibition, hyperactivity, conscientiousness, obsession, addictive behavior, motor coordination and planning, attention span, performance speed, continuous performance without intrusion and interference errors, copying and recall, concept formation, anticipatory behavior, memory span, working memory, executive planning, visuo-spatial organization, mental flexibility, conceptual shift, problem solving, programming of complex motor sequences, impulse control, judgment and forecasting of consequences.
- Physical health and risk of other conditions
- Patients with epilepsy face a greater risk of accidents, injury and other medical conditions than the general population. A European study showed that people with epilepsy were at greater risk for accidental injuries related to seizures such as concussions, abrasions and wounds and reported more hospitalizations and medical action than the general population. Other studies have shown that people with epilepsy are at a greater risk of seizure related drowning, suffocation, broken bones and burns and more likely to die in a fatal automobile crash.
- Epilepsy Ontario reports that people with epilepsy are also more likely to have other conditions than the general population such as: 30% of autistic children have epilepsy, 33% of cerebral palsy patients have epilepsy, 15-20% of fragile X syndrome patients have epilepsy, 50% of children with learning disabilities will have some form of epilepsy, 3-10% of patients with Lennox-Gastaut syndrome will have epilepsy, 80% of children with Rett syndrome will have epilepsy and 80% of patients with Tuberous Sclerosis will have epilepsy.
- Mental and emotional health
- Epileptic patients are more prone to suffer psychological and social dysfunction than individuals that do not have epilepsy. They report higher levels of anxiety and stress due to social isolation, discrimination, the unpredictability of their seizures and people’s reactions to them as well as fear of injury, death and brain damage from their seizures. Anticonvulsants can also result in lower functioning, depression, sluggishness and suicidal thoughts. Approximately 20% of people with epilepsy are depressed and the rate of suicide amongst people with epilepsy is 5 times the rate in the general population.
- People with frontal lobe epilepsy experience more significant social effects because the manifested symptoms are more unusual. Symptoms such as screaming, bicycling limbs, pelvic thrusting, inhibition control and other outbursts can be particularly embarrassing and isolating for the patient.
Tremor can be a symptom associated with disorders in those parts of the brain that control muscles throughout the body or in particular areas, such as the hands. Neurological disorders or conditions that can produce tremor include multiple sclerosis, stroke, traumatic brain injury, chronic kidney disease and a number of neurodegenerative diseases that damage or destroy parts of the brainstem or the cerebellum, Parkinson's disease being the one most often associated with tremor. Other causes include the use of drugs (such as amphetamines, cocaine, caffeine, corticosteroids, SSRIs) or alcohol, mercury poisoning, or the withdrawal of drugs such as alcohol or benzodiazepine. Tremors can also be seen in infants with phenylketonuria (PKU), overactive thyroid or liver failure. Tremors can be an indication of hypoglycemia, along with palpitations, sweating and anxiety.
Tremor can also be caused from lack of sleep, lack of vitamins, or increased stress. Deficiencies of magnesium and thiamine have also been known to cause tremor or shaking, which resolves when the deficiency is corrected. See magnesium in biology. Some forms of tremor are inherited and run in families, while others have no known cause. Tremors can also be caused by some spider bites, e.g. the redback spider of Australia.
Characteristics may include a rhythmic shaking in the hands, arms, head, legs, or trunk; shaky voice; and problems holding things such as a fork or pen. Some tremors may be triggered by or become exacerbated during times of stress or strong emotion, when the individual is physically exhausted, or during certain postures or movements.
Tremor may occur at any age but is most common in middle-age and older persons. It may be occasional, temporary, or occur intermittently. Tremor affects men and women equally.
Current medical science does not precisely describe the causes of dystonia. Misfiring of neurons in the sensorimotor cortex, a thin layer of neural tissue that covers the brain, is thought to cause contractions. This misfiring may result from impaired inhibitory mechanisms during muscle contraction. When the brain tells a given muscle to contract, it simultaneously silences muscles that would oppose the intended movement. It appears that dystonia interferes with the brain's ability to inhibit those surrounding muscles, leading to loss of selectivity.
The sensorimotor cortex is organized as discrete "maps" of the human body. Under normal conditions, each body part (such as individual fingers) occupies a distinct area on these cortical maps. In dystonia, these maps lose their distinct borders and overlap occurs. Exploration of this initially involved over-training particular finger movements in non-human primates, which resulted in the development of focal hand dystonia. Examination of the primary somatosensory cortex in the trained animals showed grossly distorted representations of the maps pertaining to the fingers when compared to the untrained animals. Additionally, these maps in the dystonic animals had lost the distinct borders that were noted in the untrained animals.
Imaging studies in humans with focal dystonia have confirmed this finding. Also, synchronous afferent stimulation of peripheral muscles induces organizational changes in motor representations, characterized both by an increase in map size of stimulated muscles and a reduction in map separation, as assessed using transcranial magnetic stimulation.
The cross-connectivity between areas that are normally segregated in the sensory cortex may prevent normal sensorimotor feedback and so contribute to the observed co-contraction of antagonist muscle groups, and inappropriately timed and sequenced movements that underlie the symptoms of focal dystonia. It is hypothesized that a deficit in inhibition caused by a genetically mediated loss of inhibitory interneurons may be the underlying cause of the deficits observed in dystonia.
While usually painless, in some instances the sustained contraction and abnormal posturing in dystonia cause pain. Focal dystonia most typically affects people who rely on fine motor skills—musicians, writers, surgeons, etc. It is thought that the excessive motor training those skills require may contribute to the development of dystonia as their cortical maps become enlarged and begin to overlap. Focal dystonia is generally "task-specific," meaning that it is only problematic during certain activities.
Late-onset dyskinesia, also known as tardive dyskinesia, occurs after long-term treatment with an antipsychotic drug such as haloperidol (Haldol) or amoxapine (Asendin). The symptoms include tremors and writhing movements of the body and limbs, and abnormal movements in the face, mouth, and tongue including involuntary lip smacking, repetitive pouting of the lips, and tongue protrusions.
Rabbit syndrome is another type of chronic dyskinesia, while orofacial dyskinesia may be related to persistent replication of Herpes simplex virus type 1.
This condition is often treated with injections of botox, a commercially prepared form of botulinum toxin. Botox reduces the symptoms of the disorder but it is not a cure for dystonia. Since the root of the problem is neurological, doctors have explored sensorimotor retraining activities to enable the brain to "rewire" itself and eliminate dystonic movements. The work of several doctors such as Nancy Byl and Joaquin Farias has shown that sensorimotor retraining activities and proprioceptive stimulation can induce neuroplasticity, making it possible for patients to recover substantial function that was lost to focal dystonia.
Anticholinergics such as Artane can be prescribed for off-label use, as some sufferers have had success.
Bass guitarist and instructor Scott Devine said that he wears a glove while playing bass guitar because of the condition. He finds that the glove stops the involuntary finger movements. He says it works for him but does not suggest that it may work for everyone with the condition.
Eliminating tremor “triggers” such as caffeine and other stimulants from the diet is often recommended.
Essential tremor may benefit from slight doses of ethanol, but the potential negative consequences of regular ethanol intake need to be taken into account. Beta blockers have been used as an alternative to alcohol in sports such as competitive dart playing and carry less potential for addiction.
Physical therapy and occupational therapy may help to reduce tremor and improve coordination and muscle control for some patients. A physical therapist and/or occupational therapist will evaluate the patient for tremor positioning, muscle control, muscle strength, and functional skills. Teaching the patient to brace the affected limb during the tremor or to hold an affected arm close to the body is sometimes useful in gaining motion control. Coordination and balancing exercises may help some patients. Some occupational therapists recommend the use of weights, splints, other adaptive equipment, and special plates and utensils for eating.
The medical treatment of essential tremor at the Movement Disorders Clinic at Baylor College of Medicine begins with minimizing stress and tremorgenic drugs along with recommending a restricted intake of beverages containing caffeine as a precaution, although caffeine has not been shown to significantly intensify the presentation of essential tremor. Alcohol amounting to a blood concentration of only 0.3% has been shown to reduce the amplitude of essential tremor in two-thirds of patients; for this reason it may be used as a prophylactic treatment before events during which one would be embarrassed by the tremor presenting itself. Using alcohol regularly and/or in excess to treat tremors is highly unadvisable, as there is a purported correlation between tremor and alcoholism. Alcohol is thought to stabilize neuronal membranes via potentiation of GABA receptor-mediated chloride influx. It has been demonstrated in essential tremor animal models that the food additive 1-octanol suppresses tremors induced by harmaline, and decreases the amplitude of essential tremor for about 90 minutes.
Two of the most valuable drug treatments for essential tremor are propranolol, a beta blocker, and primidone, an anticonvulsant. Propranolol is much more effective for hand tremor than head and voice tremor. Some beta-adrenergic blockers (beta blockers) are not lipid-soluble and therefore cannot cross the blood–brain barrier (propranolol being an exception), but can still act against tremors; this indicates that this drug’s mechanism of therapy may be influenced by peripheral beta-adrenergic receptors. Primidone’s mechanism of tremor prevention has been shown significantly in controlled clinical studies. The benzodiazepine drugs such as diazepam and barbiturates have been shown to reduce presentation of several types of tremor, including the essential variety. Controlled clinical trials of gabapentin yielded mixed results in efficacy against essential tremor while topiramate was shown to be effective in a larger double-blind controlled study, resulting in both lower Fahn-Tolosa-Marin tremor scale ratings and better function and disability as compared to placebo.
It has been shown in two double-blind controlled studies that injection of botulinum toxin into muscles used to produce oscillatory movements of essential tremors, such as forearm, wrist and finger flexors, may decrease the amplitude of hand tremor for approximately three months and that injections of the toxin may reduce essential tremor presenting in the head and voice. The toxin also may help tremor causing difficulty in writing, although properly adapted writing devices may be more efficient. Due to high incidence of side effects, use of botulinum toxin has only received a C level of support from the scientific community.
Deep brain stimulation toward the ventral intermediate nucleus of the thalamus and potentially the subthalamic nucleus and caudal zona incerta nucleus have been shown to reduce tremor in numerous studies. That toward the ventral intermediate nucleus of the thalamus has been shown to reduce contralateral and some ipsilateral tremor along with tremors of the cerebellar outflow, head, resting state and those related to hand tasks; however, the treatment has been shown to induce difficulty articulating thoughts (dysarthria), and loss of coordination and balance in long-term studies. Motor cortex stimulation is another option shown to be viable in numerous clinical trials.