The effects of myoclonus in an individual can vary depending on the form and the overall health of the individual. In severe cases, particularly those indicating an underlying disorder in the brain or nerves, movement can be extremely distorted and limit ability to normally function, such as in eating, talking, and walking. In these cases, treatment that is usually effective, such as clonazepam and sodium valproate, may instead cause adverse reaction to the drug, including increased tolerance and a greater need for increase in dosage. However, the prognosis for more simple forms of myoclonus in otherwise healthy individuals may be neutral, as the disease may cause few to no difficulties. Other times the disease starts simply, in one region of the body, and then spreads.

Research on myoclonus is supported through the National Institute of Neurological Disorders and Stroke (NINDS). The primary focus of research is on the role of neurotransmitters and receptors involved in the disease. Identifying whether or not abnormalities in these pathways cause myoclonus may help in efforts to develop drug treatments and diagnostic tests. Determining the extent that genetics play in these abnormalities may lead to potential treatments for their reversal, potentially correcting the loss of inhibition while enhancing mechanisms in the body that would compensate for their effects.

Many drugs used to treat myoclonus dystonia do not have a significant impact individually, but when combined, can work on different brain mechanisms to best alleviate symptoms. The method of treatment used depends on the severity of the symptoms presented in the individual, and whether the underlying cause of the syndrome is known.

Deep brain stimulation (DBS) has been found to be an effective and safe treatment for myoclonus dystonia patients, whose severe and debilitating symptoms are resistant to drug treatments. Electrical stimulation within the brain is a common treatment for many movement disorders because of the ability to excite or inhibit neurons within the brain. Deep brain stimulation patients have electrodes inserted into the brain and then an electrical signal is sent from an external source to elicit a response. The frequency and intensity of this signal can be changed to monitor the effects on neuronal activity using voltage recordings or neuroimaging, like functional MRIs. By re-positioning the electrodes in different areas or changing the size or timing of the stimulus, varying effects can be seen on the patient depending on the origin of the disorder.

In one study, five patients with genetically determined epsilon sarcoglycan protein deficiency underwent deep brain stimulation of the internal pallidum. Each patient’s movement and disability symptoms were assessed before and after treatment using the Burke-Fahn-Marsden Dystonia Rating Scale and the Unified Myoclonus Rating Scale. Upon completion of the surgery, both the myoclonus and dystonia symptoms of the disorder had decreased by 70%, with no report of unfavorable side effects. Therefore, deep brain stimulation has been shown to effectively improve both myoclonus and dystonia, unlike many drug treatments which may improve one or the other.

Other studies examined the effects of DBS to both the ventrointermediate nucleus of the thalamus, Vim, and the globus pallidus interna, GPi. Following deep brain stimulation of GPi and Vim, the Unified Myoclonus Rating Scale disability score improved 61-66%. In addition, the Dystomia Rating Scale score improved by 45-48%. While there was no significant difference in improvement between GPi-Vim stimulation and GPi stimulation, GPi-Vim stimulation was significantly more effective than Vim deep brain stimulation alone. Overall, Deep brain stimulation shows promise as a viable treatment for myoclonus dystonia.

Although myoclonus and dystonia are present in myoclonus dystonia patients, optimum treatment for myoclonus dystonia differs from the treatment for myoclonus or dystonia alone. Myoclonus improved significantly more than dystonia when Deep brain stimulation was applied. In addition, myoclonus improved regardless of whether Deep brain stimulation was applied to GPi or Vim. However, GPi stimulation was more effective at reducing the symptoms of dystonia than Vim stimulation.

Treatment of primary dystonia is aimed at reducing symptoms such as involuntary movements, pain, contracture, embarrassment, and to restore normal posture and improve the patient’s function. This treatment is therefore not neuroprotective. According to the European Federation of Neurological Sciences and Movement Disorder Society, there is no evidence-based recommendation for treating primary dystonia with antidopaminergic or anticholinergic drugs although recommendations have been based on empirical evidence. Anticholinergic drugs prove to be most effective in treating generalized and segmental dystonia, especially if dose starts out low and increases gradually. Generalized dystonia has also been treated with such muscle relaxants as the benzodiazepines. Another muscle relaxant, baclofen, can help reduce spasticity seen in cerebral palsy such as dystonia in the leg and trunk. Treatment of secondary dystonia by administering levodopa in dopamine-responsive dystonia, copper chelation in Wilson’s disease, or stopping the administration of drugs that may induce dystonia have been proven effective in a small number of cases. Physical therapy has been used to improve posture and prevent contractures via braces and casting, although in some cases, immobilization of limbs can induce dystonia, which is by definition known as peripherally induced dystonia. There are not many clinical trials that show significant efficacy for particular drugs, so medical of dystonia must be planned on a case-by-case basis. Botulinum toxin B, or Myobloc, has been approved by the US Food and Drug Administration to treat cervical dystonia due to level A evidential support by the scientific community. Surgery known as GPi DBS (Globus Pallidus Pars Interna Deep Brain Stimulation) has come to be popular in treating phasic forms of dystonia, although cases involving posturing and tonic contractions have improved to a lesser extent with this surgery. A follow-up study has found that movement score improvements observed one year after the surgery was maintained after three years in 58% of the cases. It has also been proven effective in treating cervical and cranial-cervical dystonia.

The diagnosis can be confirmed when the characteristic centrotemporal spikes are seen on electroencephalography (EEG). Typically, high-voltage spikes followed by slow waves are seen. Given the nocturnal activity, a sleep EEG can often be helpful. Technically, the label "benign" can only be confirmed if the child's development continues to be normal during follow-up. Neuroimaging, usually with an MRI scan, is only advised for cases with atypical presentation or atypical findings on clinical examination or EEG.

The disorder should be differentiated from several other conditions, especially centrotemporal spikes without seizures, centrotemporal spikes with local brain pathology, central spikes in Rett syndrome and fragile X syndrome, malignant Rolandic epilepsy, temporal lobe epilepsy and Landau-Kleffner syndrome.

Treatment of tics present in conditions such as Tourette’s syndrome begins with patient, relative, teacher and peer education about the presentation of the tics. Sometimes, pharmacological treatment is unnecessary and tics can be reduced by behavioral therapy such as habit-reversal therapy and/or counseling. Often this route of treatment is difficult because it depends most heavily on patient compliance. Once pharmacological treatment is deemed most appropriate, lowest effective doses should be given first with gradual increases. The most effective drugs belong to the neuroleptic variety such as monoamine-depleting drugs and dopamine receptor-blocking drugs. Of the monoamine-depleting drugs, tetrabenazine is most powerful against tics and results in fewest side effects. A non-neuroleptic drug found to be safe and effective in treating tics is topiramate. Botulinum toxin injection in affected muscles can successfully treat tics; involuntary movements and vocalizations can be reduced, as well as life-threatening tics that have the potential of causing compressive myelopathy or radiculopathy. Surgical treatment for disabling Tourette’s syndrome has been proven effective in cases presenting with self-injury. Deep Brain Stimulation surgery targeting the globus pallidus, thalamus and other areas of the brain may be effective in treating involuntary and possibly life-threatening tics.

Benign neonatal sleep myoclonus (BNSM) is the occurrence of myoclonus (jerky movements) during sleep. It is not associated with seizures.

Occurs in the first few weeks of life, usually resolves in first 2–3 months of life. Often worries parents because they appear like seizures, but they are not. Features that can help distinguish this condition from seizures include: The myoclonic movements only occur during sleep, when baby is woken up the myoclonic movements stop, normal EEG, normal neurological examination, normal developmental examination. The myoclonic jerks occur during non-REM sleep

Myoclonic epilepsy refers to a family of epilepsies that present with myoclonus. When myoclonic jerks are occasionally associated with abnormal brain wave activity, it can be categorized as myoclonic seizure. If the abnormal brain wave activity is persistent and results from ongoing seizures, then a diagnosis of myoclonic epilepsy may be considered.

The prognosis for Rolandic seizures is invariably excellent, with probably less than 2% risk of developing absence seizures and less often GTCS in adult life.

Remission usually occurs within 2–4 years from onset and before the age of 16 years. The total number of seizures is low, the majority of patients having fewer than 10 seizures; 10–20% have just a single seizure. About 10–20% may have frequent seizures, but these also remit with age.

Children with Rolandic seizures may develop usually mild and reversible linguistic, cognitive and behavioural abnormalities during the active phase of the disease. These may be worse in children with onset of seizures before 8 years of age, high rate of occurrence and multifocal EEG spikes.

The development, social adaptation and occupations of adults with a previous history of Rolandic seizures were found normal.

The most commonly effective treatment is clonazepam, which leads to the increased efficacy of another inhibitory neurotransmitter, GABA. There are anecdotal reports of the use of Levetiracetam in genetic and acquired hyperekplexia. During attacks of hypertonia and apnea, the limbs and head may be flexed towards the trunk in order to dissipate the symptoms. This is named the Vigevano maneuver after the doctor who invented it.

Because OMS is so rare and occurs at an average age of 19 months (6 to 36 months), a diagnosis can be slow. Some cases have been diagnosed as having been caused by a virus. After a diagnosis of OMS is made, an associated neuroblastoma is discovered in half of cases, with median delay of 3 months.

The interictal EEG pattern is usually normal.

SPS is diagnosed by evaluating clinical findings and excluding other conditions. There is no specific laboratory test that confirms its presence. Underdiagnosis and misdiagnosis are common.

The presence of antibodies against GAD is the best indication of the condition that can be detected by blood and cerebrospinal fluid (CSF) testing. Anti-GAD65 is found in about 80 percent of SPS patients. Anti-thyroid, anti-intrinsic factor, anti-nuclear, anti-RNP, and anti-gliadin are also often present in blood tests. Electromyography (EMG) demonstrates involuntary motor unit firing in SPS patients. EMG can confirm the diagnosis by noting spasms in distant muscles as a result of subnoxious stimulation of cutaneous or mixed nerves. Responsiveness to diazepam helps confirm that the patient is suffering from SPS, as this decreases stiffness and motor unit potential firing.

The same general criteria are used to diagnose paraneoplastic SPS as the normal form of the condition. Once SPS is diagnosed, poor response to conventional therapies and the presence of cancer indicate that it may be paraneoplastic. CT scans are indicated for SPS patients who respond poorly to therapy to determine if this is the case.

A variety of conditions have similar symptoms to SPS, including myelopathies, dystonias, spinocerebellar degenerations, primary lateral sclerosis, neuromyotonia, and some psychogenic disorders. Tetanus, neuroleptic malignant syndrome, malignant hyperpyrexia, chronic spinal interneuronitis, serotonin syndrome, Multiple sclerosis, Parkinson's disease, and Isaacs syndrome should also be excluded.

Patients' fears and phobias often incorrectly lead doctors to think their symptoms are psychogenic, and they are sometimes suspected of malingering. It takes an average of six years after the onset of symptoms before the disease is diagnosed.

PLMD is often treated with anti-Parkinson medication; it may also respond to anticonvulsants, benzodiazepines, and narcotics. Patients must stay on these medications in order to experience relief, because there is no known cure for this disorder.

PLMs tend to be exacerbated by tricyclic antidepressants, SSRIs, stress, and sleep deprivation. It is also advised not to consume caffeine, alcohol, or antidepressants as these substances could worsen the PLMD symptoms.

Other medications aimed at reducing or eliminating the leg jerks or the arousals can be prescribed. Non-ergot derived dopaminergic drugs (pramipexole and ropinirole) are preferred. Other dopaminergic agents such as co-careldopa, co-beneldopa, pergolide, or lisuride may also be used. These drugs decrease or eliminate both the leg jerks and the arousals. These medications are also successful for the treatment of restless legs syndrome.

In one study, co-careldopa was superior to dextropropoxyphene in decreasing the number of leg kicks and the number of arousals per hour of sleep. However, co-careldopa and, to a lesser extent, pergolide may shift the leg movements from the nighttime to the daytime.

Clonazepam (Klonopin), in doses of 1 mg has been shown to improve objective and subjective measures of sleep.

Currently there are no clinically established laboratory investigations available to predict prognosis or therapeutic response.

Tumors in children who develop OMS tend to be more mature, showing favorable histology and absence of n-myc oncogene amplification than similar tumors in children without symptoms of OMS. Involvement of local lymph nodes is common, but these children rarely have distant metastases and their prognosis, in terms of direct morbidity and mortality effects from the tumor, is excellent. The three-year survival rate for children with non-metastatic neuroblastoma and OMS was 100% according to Children’s Cancer Group data (gathered from 675 patients diagnosed between 1980 and 1994); three-year survival in comparable patients with OMS was 77%. Although the symptoms of OMS are typically steroid-responsive and recovery from acute symptoms of OMS can be quite good, children often suffer lifelong neurologic sequelae that impair motor, cognitive, language, and behavioral development.

Most children will experience a relapsing form of OMS, though a minority will have a monophasic course and may be more likely to recover without residual deficits. Viral infection may play a role in the reactivation of disease in some patients who had previously experienced remission, possibly by expanding the memory B cell population. Studies have generally asserted that 70-80% of children with OMS will have long-term neurologic, cognitive, behavioral, developmental, and academic impairment. Since neurologic and developmental difficulties have not been reported as a consequence of neuroblastoma or its treatment, it is thought that these are exclusively due to the immune mechanism underlying OMS.

One study concludes that: ""Patients with OMA and neuroblastoma have excellent survival but a high risk of neurologic sequelae. Favourable disease stage correlates with a higher risk for development of neurologic sequelae. The role of anti-neuronal antibodies in late sequelae of OMA needs further clarification"."

Another study states that: ""Residual behavioral, language, and cognitive problems occurred in the majority"."

PME accounts for less than 1% of epilepsy cases at specialist centres. The incidence and prevalence of PME is unknown, but there are considerable geography and ethnic variations amongst the specific genetic disorders. One cause, Unverricht Lundborg Disease, has an incidence of at least 1:20,000 in Finland.

Treatment of Ramsay Hunt Syndrome Type 1 is specific to individual symptoms. Myoclonus and seizures may be treated with drugs like valproate.

Some have described this condition as difficult to characterize.

PLMD is estimated to occur in approximately 4% of adults (aged 15–100), but is more common in the elderly, especially females, with up to 11% experiencing symptoms. PLMD appears to be related to restless legs syndrome (RLS) - a study of 133 people found that 80% of those with RLS also had PLMD. However the opposite is not true: many people who have PLMD do "not" also have restless legs syndrome.

Non-epileptic seizures are paroxysmal events that mimic an epileptic seizure but do not involve abnormal, rhythmic discharges of cortical neurons. They are caused by either physiological or psychological conditions. The latter is discussed more fully in psychogenic non-epileptic seizures.

[Please could somebody add an actual description of what happens when somebody has a seizure or 'paroxysmal event'?!]

A wide array of phenomena may resemble epileptic seizures, which may lead to people who do not have epilepsy being misdiagnosed. Indeed, a significant percentage of people initially diagnosed with epilepsy will later have this revised. In one study, the majority of children referred to a secondary clinic with "fits, faints and funny turns" did not have epilepsy, with syncope (fainting) as the most common alternative. In another study, 39% of children referred to a tertiary epilepsy centre did not have epilepsy, with staring episodes in mentally challenged children as the most common alternative. In adults, the figures are similar, with one study reporting a 26% rate of misdiagnosis.

Differentiation of a non-epileptic attack from an epileptic seizure includes the patient keeping their eyes closed and rarely causing themselves harm (both more common in non-epileptic attacks)

The three main signs of hyperekplexia are generalized stiffness, excessive startle beginning at birth and nocturnal myoclonus. Affected individuals are fully conscious during episodes of stiffness, which consist of forced closure of the eyes and an extension of the extremities followed by a period of generalised stiffness and uncontrolled falling at times. Initially, the disease was classified into a "major" and a "minor" form, with the minor form being characterized by an excessive startle reflex, but lacking stiffness. There is only genetic evidence for the existence of the major form.

Other signs and symptoms of hyperekplexia may include episodic neonatal apnea, excessive movement during sleep and the head-retraction reflex. The link to some cases of Sudden Infant Death remains controversial.

The only currently available method to diagnose Unverricht–Lundborg disease is a genetic test to check for the presence of the mutated cystatin B gene. If this gene is present in an individual suspected of having the disease, it can be confirmed. However, genetic tests of this type are prohibitively expensive to perform, especially due to the rarity of ULD. The early symptoms of ULD are general and in many cases similar to other more common epilepsies, such as juvenile myoclonic epilepsy. For these reasons, ULD is generally one of the last options doctors explore when looking to diagnose patients exhibiting its symptoms. In most cases, a misdiagnosis is not detrimental to the patient, because many of the same medications are used to treat both ULD and whatever type of epilepsy the patient has been misdiagnosed with. However, there are a few epilepsy medications that increase the incidence of seizures and myoclonic jerks in patients with ULD, which can lead to an increase in the speed of progression, including phenytoin, fosphenytoin, sodium channel blockers, GABAergic drugs, gabapentin and pregabalin.

Other methods to diagnose Unverricht–Lundborg disease are currently being explored. While electroencephalogram (EEG) is useful in identifying or diagnosing other forms of epilepsy, the location of seizures in ULD is currently known to be generalized across the entire brain. Without a specific region to pinpoint, it is difficult to accurately distinguish an EEG reading from an individual with ULD from an individual with another type of epilepsy characterized by generalized brain seizures. However, with recent research linking ULD brain damage to the hippocampus, the usefulness of EEG as a diagnostic tool may increase.

Magnetic Resonance Imaging (MRI) is also often used during diagnosis of patients with epilepsy. While MRIs taken during the onset of the disease are generally similar to those of individuals without ULD, MRIs taken once the disease has progressed show characteristic damage, which may help to correct a misdiagnosis.

While ULD is a rare disease, the lack of well defined cases to study and the difficulty in confirming diagnosis provide strong evidence that this disease is likely under diagnosed.

Since lateral medullary syndrome is often caused by a stroke, diagnosis is time dependent. Diagnosis is usually done by assessing vestibular-related symptoms in order to determine where in the medulla that the infarction has occurred. Head Impulsive Nystagmus Test of Skew (HINTS) examination of oculomotor function is often performed, along with computed tomography (CT) or magnetic resonance imaging (MRI) to assist in stroke detection. Standard stroke assessment must be done to rule out a concussion or other head trauma.

A detailed family history should be obtained from at least three generations. In particularly a history to determine if there has been any neonatal and childhood deaths: Also a way to determine if any one of the family members exhibit any of the features of the multi-system disease. Specifically if there has been a maternal inheritance, when the disease is transmitted to females only, or if there is a family member who experienced a multi system involvement such as: Brain condition that a family member has been record to have such asseizures, dystonia, ataxia, or stroke like episodes.The eyes with optic atrophy, the skeletal muscle where there has been a history of myalgia, weakness or ptosis. Also in the family history look for neuropathy and dysautonomia, or observe heart conditions such ascardiomyopathy. The patients history might also exhibit a problem in their kidney, such as proximal nephron dysfunction. An endocrine condition, for example diabetes and hypoparathyroidism. The patient might have also had gastrointestinal condition which could have been due to liver disease, episodes of nausea or vomiting. Multiple lipomas in the skin, sideroblastic anemia and pancytopenia in the metabolic system or short stature might all be examples of patients with possible symptoms of MERRF disease.

The progression of SPS depends on whether it is a typical or abnormal form of the condition and the presence of comorbidities. Early recognition and neurological treatment can limit its progression. SPS is generally responsive to treatment, but the condition usually progresses and stabilizes periodically. Even with treatment, quality of life generally declines as stiffness precludes many activities. Some patients require mobility aids due to the risk of falls. About 65 percent of SPS patients are unable to function independently. About ten percent of SPS patients require intensive care at some point; sudden death occurs in about the same number of patients. These deaths are usually caused by metabolic acidosis or an autonomic crisis.