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Abnormal involuntary movement (AIM) are usually classified into hypokinesia and hyperkinesia group. Hyperkinesia-AIM includes myoclonus, chorea, ballism, dystonia, athetosis, and more. Of these, dystonia, myoclonus, and chorea are frequent movement disorders. From a neurophysiological point of view, the mechanism of motor control by the basal ganglia is thought to consist of three pathways: hyperdirect, direct, and indirect. Hyperkinetic-AIMs are likely caused by the dysfunction of any of these three pathways, leading to malfunction in either presurround inhibition, initiation of motor performance, or postsurround inhibition. These dysfunctions are assumed to stem from regions, such as the cerebral cortex, white matter, basal ganglia, brainstem, and cerebellum. Drug therapies that consider the pathogenesis mechanism are desirable. Here, we presented an overview of treatment methods for hyperkinetic-AIMs.

Stereotactic and functional neurosurgery(deep brain stimulation[DBS]and radiofrequency coagulation)is an established method of treatment for patients with Parkinson's disease, tremor, and/or dystonia. The surgery involves many pitfalls and is similar to other surgeries, requiring experience and skills. Here, we have discussed three categories of DBS-related complications, including surgical procedure-related and device-related complications, and stimulation-induced side effects. In addition, we have discussed the prevention and coping methods, including those not listed in the guidelines for stereotactic and functional neurosurgery.

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements or postures. Currently, dystonia is defined as a network disorder involving the basal ganglia, cerebellum, thalamus, and sensorimotor cortex. Considering that it is refractory to medical therapy, functional neurosurgery is indispensable in the treatment strategy for dystonia. Functional neurosurgery may improve dystonic symptoms by suppressing abnormal neuronal activity in the motor loop network. Deep brain stimulation(DBS)of the globus pallidus internus(GPi)is a useful surgical treatment for genetically defined and primary dystonia involving the axial musculature. Thalamic ventral oral(Vo)nucleus surgery is recommended for cases of peripheral dystonia, such as writer's cramp and other occupational types of dystonia. However, pallidal DBS is less effective in cases of secondary dystonia, with the exception of tardive dystonia. Recent studies have reevaluated that ablation surgery is the last-resort treatment when DBS must be discontinued for certain conditions. Magnetic resonance-guided focused ultrasound(MRgFUS), a novel, incision-free, ablation technique, is currently used for the treatment of focal hand dystonia.

Deep brain stimulation(DBS)is an effective therapy for conditions involving drug-resistant involuntary movements, such as Parkinson's disease, tremor, and dystonia. Programming of DBS, as well as strict surgical indications, appropriate target selection, and accurate electrode placement, is one of the most important factors in the success of DBS. To obtain effective stimulation for a long period, it is important to expand the therapeutic window and reduce side effects. Recent advances in DBS devices have dramatically expanded the variety of stimulus settings. While the indication criteria of DBS and surgical techniques have been established, the details of the programming algorithm are not yet unified. In this paper, we describe the features of each device, basic programming methods, management of DBS-related side effects, and advanced stimulus methods.

Six cases of dystonic tremor were treated with the Vercise TM deep brain stimulation(DBS)system, which has the multiple independent current control(MICC)technology. The mean preoperative score of Burke-Fahn-Marsden dystonia rating scale was 16.2±9.4, which was reduced to 6.1±4.6 at 5 months postoperatively. A 65-year-old male presented an intractable dystonic tremor of the jaw, neck, and shoulders due to tardive syndrome. He experienced the successful tremor relief after unipolar DBS in the globus pallidus internus(GPi)with Vercise TM but complained of dysarthria. Steering the current ventrally induced nausea without alleviating dysarthria, while steering the current dorsally alleviated dysarthria but a further dorsal current induced mandibular dyskinesia. The current steering with MICC enabled the simulation field in GPi with successful balance, maximizing tremor suppression, and minimizing the adverse effects. In a second case, 61-year-old male in whom cervical dystonia with rotatory tremor had been successfully treated with interleaving stimulation of GPi-DBS had needed to repeat the replacement of a non-rechargeable pulse generator in only 15-month interval. After the substitution of Vercise TM , the interleaving stimulation of 9.5mA in total was replaced by 8.5mA with the current steering of MICC, while the patient's symptomatic control was unchanged. The microlesion effects after lead implantation are unclear and therapeutic effects are often delayed in cases of dystonia;therefore, the submaximal stimulation intensities must be frequently applied in the early phase following the implantation of DBS. A fine current steering of Vercise TM DBS is very useful in both, the early and late phases of GPi-DBS for dystonic syndrome.

Identification of causative genes for hereditary dystonia and elucidation of their functions are crucial for better understanding of dystonia pathogenesis. As seen in other hereditary neurologic disorders, intra- and inter-familial clinical variations have been demonstrated in hereditary dystonia. Asymptomatic carriers can be found due to alterations in penetrance, generally reduced in succeeding generations. Current known dystonia genes include those related to dopamine metabolism, transcription factor, cytoskeleton, transport of glucose and sodium ion, etc. It has been reported that effects of deep brain stimulation can vary significantly depending on genotype. Accumulation of genotype-outcome correlations would contribute to treatment decisions for dystonia patients.

Deep brain stimulation (DBS) has been widely performed for various medically refractory movement disorders. For Parkinson disease (PD), target of DBS is subthalamic nucleus (STN) or globus pallidus internus (GPi). There are some evidences to demonstrate its effectiveness on motor function and QOL. DBS effectively improves levodopa-responsive motor symptoms, and significantly reduces dyskinesia and motor fluctuations. STN DBS particularly decreases the need for dopaminergic medication. A combination of medical treatment and DBS would provide longer relief of motor symptoms than medical treatment only. Currently new evidence supporting early introduction of DBS for better future outcome is published. DBS of Vim thalamus has been indicated for intractable tremor with various etiologies. Recently posterior subthalamic area (PSA) is introduced as an alternative target to Vim for tremor. GPi DBS is also effective treatment option for generalized dystonia.

Dystonia is defined as a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures. Its diagnosis is based on clinical characteristics. In dystonia, the pattern of abnormal posture or movement tends to be constant during the short term even if its severity fluctuates. This stereotypy often helps differentiate dystonia from psychogenic reaction. Dystonia may appear only during some specific task (task specificity) especially in its early phase, although it often becomes obscure during the long clinical course, resulting in persistent dystonic posture. Sensory trick or geste antagoniste means the change of severity triggered by some sensory input Overflow phenomenon is the activation of muscles unnecessary to a task, hampering purposeful movement. Symptoms tend to be milder in the morning, with large individual variation of its duration (morning benefit). Symptoms of dystonia may abruptly appear or disappear (flip-flop phenomenon). Cocontraction, believed as an essential feature of dystonia, reflects a loss of reciprocal inhibition of muscle activities, causing involuntary simultaneous contractions of agonists and antagonists. "Negative dystonia," still an unaccepted feature of dystonia, is defined as non-paretic loss of central driving of muscle activities necessary to a task. Apraxia of lid opening/closure, paretic form of hand dystonia, dropped head syndrome, camptocormia, Pisa syndrome, cervical dystonia with limited range of head movement, or mandibular dystonia without cocontractions of masticatory muscles, can be explained with this concept at least in a subset of cases. Treatment of dystonia includes medication, botulinum toxin injection, intrathecal baclofen, surgical intervention, acupuncture and other alternative therapies, rehabilitation, and psychotherapy. Oral medication is usually an adjunct to more potent therapeutic options except for some specific indications like dopa-responsive dystonia. Botulinum toxin is usually the treatment of choice for focal dystonia. Deep brain stimulation can be considered for both focal and non-focal phenotypes of dystonia.

Gait disturbance, one of the axial symptoms, is caused by various disorders, including basal ganglia disease. Deep brain stimulation (DBS) has widened the spectrum of therapeutic options for patients with gait disturbance due to Parkinson disease and dystonia. In gait disturbance caused by basal ganglia disease, the main targets of DBS are the subthalamic nucleus (STN) and globus pallidus internus (GPi). STN DBS is more than GPi DBS effective for treating levodopa-responsive parkinsonian symptoms, including gait disturbance. GPi DBS is effective for the treatment of primary segmental or generalized dystonia. The pedunculopontine tegmental nucleus (PPN), which is involved in locomotion, is one of the new targets for treating gait disturbance in Parkinson disease. We review DBS in the treatment of gait disturbance due to Parkinson disease and dystonia.

Deep brain stimulation (DBS) has proved highly effective in the treatment for Parkinson's disease and dystonia. Presently, many types of dopamine agonists, monoamine oxidase B (MAOB) inhibitors, catechol-O-methyltransferase (COMT) inhibitor or other antiparkinsonian drugs are being developed. However, it is still very difficult to medically treat motor complications associated with levodopa therapy. Surgical intervention using DBS was possible to stimulate the subthalamic nucleus as the treatment of Parkinson's disease. Stimulation of the subthalamic nucleus improves the cardinal parkinsonian symptoms and motor complication associated with levodopa treatment. DBS is a reversible treatment and the original status could be observed by turning off the stimulation. This procedure enables the observation of clinical outcomes or brain mechanisms under both the conditions of turned on and turned off stimulations. On the other hand, dystonia is heterogeneous and refractory and hence, it has been difficult to medically treat it. Since there was no effective treatment available for patients with generalized dystonia, these patients became disabled. However, recently, bilateral pallidal DBS has been shown to markedly improve the conditions of patients with generalized dystonia, and it has proven to be a reliable treatment. There are two characteristic clinical effects of pallidal DBS on dystonia. It improves primary hereditary generalized dystonia, particularly DYT 1, more prominently than secondary dystonia and its beneficial effects are observed over a period of time course. The beneficial effects of pallidal DBS in patients with dystonia are not immediate but progress over weeks to months. The brain mechanism underlying the improvement of pallidal DBS in dystonia has been unclear. Many studies on DBS in Parkinson's disease and dystonia have been carried out to elucidate the clinical outcomes and/or the underlying neurophysiological mechanisms. In this review, the clinical outcomes of DBS for Parkinson's disease and dystonia will be focused on.

Diagnosis of dystonia is not difficult by recognizing the pattern of clinical presentation. Dopa-responsive dystonia (DRD) and Wilson disease are important in differential diagnosis because of their specific treatment. The most common are the focal dystonias, including blepharospasm and spasmodic torticollis. Dystonia comprises mobile involuntary movements and abnormal postures, the latter is better described as hypokinetic disorder. The pathogenesis of dystonia is now being clarified, and includes abnormal neuroplasticity caused by the relative excess of dopamine in the matrix compartment of the striatum, the possible primary lesion being the striosome. In a dopa-responsive dystonia model, dopaminergic projection is more deficient to the striosome than to the matrix, which could produce imbalance between the direct versus. indirect pathway activities. The treatment options include trihexyphenidyl, minor tranquilizers, botulinum toxin injection, and deep brain stimulation.

It is very complex and stressful task to play musical instruments, creating fine music. Professional musical players often complain of difficulties in manipulating their instruments skillfully. In these cases the fingers are found to be hyperflexing, upper limbs are in abnormal posture. This phenomena is named as Musician's dystonia, due to abnormal sensory-motor integration concerning manipulation of musical instruments. It is a regret for the patients that few medical doctors pay attention to the disease and misdiagnose as psychiatric problem or others very often. The hyperactivity of finger muscle should be reduced precisely. Botulinum neurotoxin is effective to treat such hypercontraction of muscles, however, in case of musician's dystonia, too much amount of its effects are not beneficial for the players because of the risk to weaken or paralyze the finger/hand becomes higher. We are trying lidocaine injection into the muscles in charge of dystonic posture/movement successfully.

We performed acupuncture treatment on first consultation for a female 28-year-old patient with severe axial dystonia, causing involuntary movement and abnormal posture of the neck and body, which had developed during treatment for schizophrenia. Involuntary movement involving elevation of the right shoulder began to occur in October X-1. Drugs were prescribed by her doctor, but her involuntary movement worsened and spread to the whole body. Thereafter, she began receiving acupuncture treatment at the out patient clinic for dystonia at the Kansai Medical College Hospital in July X. Involuntary movements of her neck involved repeated left lateral bending or a rigidly straight posture while sitting and standing. Her neck also showed a left lateral bend and right rotation. Her body showed a left lateral bend and right shoulder elevation. The neck problems in this case were induced by a hypertonicity of the left sternocleidomastoid (SCM), which caused the left lateral bending and right rotation of the neck. Problems in her body involved left lateral bending due to hypotonicity of the left abdominal muscle and hypotonicity of the left back muscles, which were unable to control the left lateral bending of the body. The right shoulder elevation was caused by a hypertonicity of the right trapezius and this was another of her problems. Acupuncture treatments were given using a penetrating needle method. The treatment points were left LI4 to decrease the hypertonicity of the left SCM, left ST41 to increase the hypotonicity of the left abdominal muscles, right BL60 to increase the hypotonicity of the right back muscles and right TE5 to decrease the hypertonicity of the right trapezius. At the initial stage of acupuncture treatment, the patient was not able to attend the hospital regularly enough to obtain sufficient improvement by acupuncture. In December X+1, she started to receive acupuncture treatment weekly, and the posture of the neck and body improved. In May X+3, her neck and body postures remained erect while sitting and she did not show involuntary movement. For problems of dystonia, we perform acupuncture treatment, using meridian and acupressure points selected based on the oriental medicine system, and we achieved improvement of symptoms in this case. The patient also achieved improved stability with regard to the symptoms of schizophrenia. It is suggested that acupuncture treatment has had a positive effect on tardive dystonia including axial dystonia.

Dyskinesia and dystonia are common complications of long-term levodopa therapy. Because peak-dose dyskinesia is due to excessive dopaminergic stimulation by anti-parkinsonian drugs, it is solved by reducing the whole dose or by taking frequent small doses of levodopa in order to keep relatively stable serum levels. It may be attenuated by dopamine receptor agonists or amantadine which acts as an N-methyl-D-aspartate (NMDA) receptor agonist. On the other hand, since early morning dystonia is related to the decline in the level of levodopa, it is initially treated by adding a small dose of levodopa in bedtime. Other patterns of dystonia are often treated accordingly to the treatment of wearing-off phenomenon.

We present a case with walking-induced equinovarus caused by dystonic contraction of the left ankle. This abnormal motor behavior occurred only when the patient walked, more specifically when the left leg was at the end of the swing phase. Surface electromyography confirmed continuous abnormal discharges in the left gastrocnemius muscles during the swing phase of walking. Brain and spinal magnetic resonance imagings (MRIs) were normal. The patient was unresponsive to drug therapy. However, the symptom reduced by the attachment of the short leg brace. From the effectiveness of the brace in normalizing, the patient was diagnosed with task-specific focal dystonia of the left leg.

We report a 67-year-old hypertensive right-handed woman who developed severe pain and dystonia in her left upper and lower extremity after a thalamic infarction. She was well until 9 months prior to the present admission to our hospital, when she had an acute onset of left hemiparesis which turned out to have been caused by a thalamic infarct. Her hemiparesis showed nearly complete recovery during the next four months. She noted an onset of severe spontaneous pain and difficulty in using her left hand four months prior to the present admission. Neurologic examination on admission revealed an alert and well oriented Japanese woman. Cranial nerves were intact. Although she did not have weakness, her left hand showed thalamic posture, and upon standing, she showed a dystonic posture in which her left forearm took pronation and flexion at the elbow joint and her left lower extremity took extension in the knee joint and planter flexion in the ankle joint. Her dystonic posture increased during walking and disappeared in the supine position. She complained of severe spontaneous pain and tingling sensation in her left extremities. Position sense was diminished in her left leg. However other sensations were intact. She had slight ataxia on the left side. Deep tendon reflexes were symmetric, but the planter response was extensor on the left side. MRI revealed a small lacunar infarct involving the right posterolateral thalamic region. EMG with surface electrodes revealed non-reciprocal tonic discharges in the left biceps brachii and forearm flexor and extensor muscles. She responded poorly to various medications. Only trihexyphenidyl showed partial alleviation of her pain and dystonic posture. We thought her pain might be caused by dystonic contraction of the skeletal muscles, at least in part. We injected 25 IU of botulinus toxin as a total dose into her biceps brachii, triceps brachii, and wrist flexor muscles. A few days after the injection, her dystonic posture began to show marked improvement; as her dystonia improved, her pain also showed marked improvement. This patient appeared to represent a case of post-hemiplegic dystonia. Her pain was initially thought to be the thalamic pain. However, as her pain disappeared with improvement of her dystonia, her pain is most likely to have been caused by the dystonic muscle contraction. Botulinus toxin treatment appears to be useful for post-hemiplegic painful dystonia.

Pathophysiologies of disorders with dystonia or myoclonus were studied by evaluating the effects of treatment. Naturally, the main lesion of the dystonia responding to levodopa is in the nigrostriatal dopamine neuron. The target of stereotaxic operations is ventrolateral palladium for postural dystonia and the nucleus ventralis oralis posterior (Vop) thalamus for action dystonia. Torsion dystonia with lesion in the striatum and/or the pallidum causes axial torsion, it may be postural through the descending pathway and action through Vop. Stereotaxic operations on these pathways have shown to be effective. Focal dystonia is a reflection of abnormal co-activation of cortical motor neurons, occurring in a particular voluntary movement. Botulinus toxin injected into the affected muscle should be effective. Of myoclonus with epilepsy, cortical reflex myoclonus or cortical induced reticular myoclonus responds to valproic acid. However, no antiepileptic drugs are effective on those with primary brainstem lesion. Reticular reflex myoclonus due to asphyxia responds to ventralis intermedius thalamotomy. Idiopathic myoclonus associated with dystonia is particular because it responds to ventrolateral thalamotomy. Myoclonus except for idiopathic myoclonus with dystonia is associated with atonic NREM suggesting dysfunction of the dorsal raphe serotonergic neuron or the brainstem nucleus reticularis gigantocellularis, the causative neuron for experimental uremic myoclonus. Treatment for these neurons is necessary.

A 29-year-old man suffered from dystonic writer's cramp for over three years. When he wrote, typed and did other tasks using right hand, dystonic involuntary movement triggered medial rotation of the arm, wrist extension and shoulder elevation. Medication, biofeedback, and botulinum injection were performed without much success. We tried to block the sensory input from muscles by using lidocaine and ethanol. We made injections of 0.5% lidocaine 50ml and 99% ethanol 5ml into muscles with abnormal activity at the frequency of twice a week for about six months. After the treatment, dystonic movement was remarkably improved and he was then able to write, type and perform other tasks with the right hand. Side effects included pain of the injection site, nausea and dizziness, which lasted for a few hours. This "muscle afferent block" did not cause muscle weakness. We speculate that muscle afferent plays a pivotal role in dystonia so that its blocking may be of clinical use.

We have studied the effect of botulinum toxin in patients with focal dystonia, not responding sufficiently to medical therapy. Injection of 5-100 units to the muscles, selected by EMG and clinical examination, invariably resulted in reduction of muscle tonus, although to a different degree depending on the dosage. The outcome after the first trial was best when dealing with small muscles in patients with blephalospasm or Meige's syndrome. In contrast, several attempts were required for the treatment of a large muscle as in torticollis, or multiple muscles as in writers' cramps. The effect lasted 1-3 months. With precise selection of the affected muscles and careful regulation of necessary dosages, this type of therapy may contribute to the treatment of focal dystonia.