Dystonia: An attitude or posture due to the co-contraction of agonists and antagonist muscles in one region of the body. It most often affects the large axial muscles of the trunk and limb girdles. Conditions which feature persistent or recurrent episodes of dystonia as a primary manifestation of disease are referred to as DYSTONIC DISORDERS. (Adams et al., Principles of Neurology, 6th ed, p77)Dystonic Disorders: Acquired and inherited conditions that feature DYSTONIA as a primary manifestation of disease. These disorders are generally divided into generalized dystonias (e.g., dystonia musculorum deformans) and focal dystonias (e.g., writer's cramp). They are also classified by patterns of inheritance and by age of onset.Dystonia Musculorum Deformans: A condition characterized by focal DYSTONIA that progresses to involuntary spasmodic contractions of the muscles of the legs, trunk, arms, and face. The hands are often spared, however, sustained axial and limb contractions may lead to a state where the body is grossly contorted. Onset is usually in the first or second decade. Familial patterns of inheritance, primarily autosomal dominant with incomplete penetrance, have been identified. (Adams et al., Principles of Neurology, 6th ed, p1078)Torticollis: A symptom, not a disease, of a twisted neck. In most instances, the head is tipped toward one side and the chin rotated toward the other. The involuntary muscle contractions in the neck region of patients with torticollis can be due to congenital defects, trauma, inflammation, tumors, and neurological or other factors.Anti-Dyskinesia Agents: Drugs used in the treatment of movement disorders. Most of these act centrally on dopaminergic or cholinergic systems. Among the most important clinically are those used for the treatment of Parkinson disease (ANTIPARKINSON AGENTS) and those for the tardive dyskinesias.Blepharospasm: Excessive winking; tonic or clonic spasm of the orbicularis oculi muscle.Meige Syndrome: A syndrome characterized by orofacial DYSTONIA; including BLEPHAROSPASM; forceful jaw opening; lip retraction; platysma muscle spasm; and tongue protrusion. It primarily affects older adults, with an incidence peak in the seventh decade of life. (From Adams et al., Principles of Neurology, 6th ed, p108)Globus Pallidus: The representation of the phylogenetically oldest part of the corpus striatum called the paleostriatum. It forms the smaller, more medial part of the lentiform nucleus.Muscle Cramp: A sustained and usually painful contraction of muscle fibers. This may occur as an isolated phenomenon or as a manifestation of an underlying disease process (e.g., UREMIA; HYPOTHYROIDISM; MOTOR NEURON DISEASE; etc.). (From Adams et al., Principles of Neurology, 6th ed, p1398)Movement Disorders: Syndromes which feature DYSKINESIAS as a cardinal manifestation of the disease process. Included in this category are degenerative, hereditary, post-infectious, medication-induced, post-inflammatory, and post-traumatic conditions.Deep Brain Stimulation: Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.Botulinum Toxins: Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS.HandwritingNeuromuscular Agents: Drugs used for their actions on skeletal muscle. Included are agents that act directly on skeletal muscle, those that alter neuromuscular transmission (NEUROMUSCULAR BLOCKING AGENTS), and drugs that act centrally as skeletal muscle relaxants (MUSCLE RELAXANTS, CENTRAL). Drugs used in the treatment of movement disorders are ANTI-DYSKINESIA AGENTS.Hand: The distal part of the arm beyond the wrist in humans and primates, that includes the palm, fingers, and thumb.Molecular Chaperones: A family of cellular proteins that mediate the correct assembly or disassembly of polypeptides and their associated ligands. Although they take part in the assembly process, molecular chaperones are not components of the final structures.Botulinum Toxins, Type A: A serotype of botulinum toxins that has specificity for cleavage of SYNAPTOSOMAL-ASSOCIATED PROTEIN 25.Nocturnal Paroxysmal Dystonia: A parasomnia characterized by paroxysmal episodes of choreoathetotic, ballistic, dystonic movements, and semipurposeful activity. The episodes occur during non-rapid eye movement sleep and typically recur several times per night. (Neurology 1992 Jul;42(7 Suppl 6):61-67; Adams et al., Principles of Neurology, 6th ed, p391)Entopeduncular Nucleus: A portion of the nucleus of ansa lenticularis located medial to the posterior limb of the internal capsule, along the course of the ansa lenticularis and the inferior thalamic peduncle or as a separate nucleus within the internal capsule adjacent to the medial GLOBUS PALLIDUS (NeuroNames, http://rprcsgi.rprc. washington.edu/neuronames/ (September 28, 1998)). In non-primates, the entopeduncular nucleus is analogous to both the medial globus pallidus and the entopeduncular nucleus of human.Levodopa: The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.GTP Cyclohydrolase: (GTP cyclohydrolase I) or GTP 7,8-8,9-dihydrolase (pyrophosphate-forming) (GTP cyclohydrolase II). An enzyme group that hydrolyzes the imidazole ring of GTP, releasing carbon-8 as formate. Two C-N bonds are hydrolyzed and the pentase unit is isomerized. This is the first step in the synthesis of folic acid from GTP. EC 3.5.4.16 (GTP cyclohydrolase I) and EC 3.5.4.25 (GTP cyclohydrolase II).Basal Ganglia Diseases: Diseases of the BASAL GANGLIA including the PUTAMEN; GLOBUS PALLIDUS; claustrum; AMYGDALA; and CAUDATE NUCLEUS. DYSKINESIAS (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include CEREBROVASCULAR DISORDERS; NEURODEGENERATIVE DISEASES; and CRANIOCEREBRAL TRAUMA.Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.Trihexyphenidyl: One of the centrally acting MUSCARINIC ANTAGONISTS used for treatment of PARKINSONIAN DISORDERS and drug-induced extrapyramidal movement disorders and as an antispasmodic.Chorea: Involuntary, forcible, rapid, jerky movements that may be subtle or become confluent, markedly altering normal patterns of movement. Hypotonia and pendular reflexes are often associated. Conditions which feature recurrent or persistent episodes of chorea as a primary manifestation of disease are referred to as CHOREATIC DISORDERS. Chorea is also a frequent manifestation of BASAL GANGLIA DISEASES.Complex Regional Pain Syndromes: Conditions characterized by pain involving an extremity or other body region, HYPERESTHESIA, and localized autonomic dysfunction following injury to soft tissue or nerve. The pain is usually associated with ERYTHEMA; SKIN TEMPERATURE changes, abnormal sudomotor activity (i.e., changes in sweating due to altered sympathetic innervation) or edema. The degree of pain and other manifestations is out of proportion to that expected from the inciting event. Two subtypes of this condition have been described: type I; (REFLEX SYMPATHETIC DYSTROPHY) and type II; (CAUSALGIA). (From Pain 1995 Oct;63(1):127-33)Dyskinesia, Drug-Induced: Abnormal movements, including HYPERKINESIS; HYPOKINESIA; TREMOR; and DYSTONIA, associated with the use of certain medications or drugs. Muscles of the face, trunk, neck, and extremities are most commonly affected. Tardive dyskinesia refers to abnormal hyperkinetic movements of the muscles of the face, tongue, and neck associated with the use of neuroleptic agents (see ANTIPSYCHOTIC AGENTS). (Adams et al., Principles of Neurology, 6th ed, p1199)Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Essential Tremor: A relatively common disorder characterized by a fairly specific pattern of tremors which are most prominent in the upper extremities and neck, inducing titubations of the head. The tremor is usually mild, but when severe may be disabling. An autosomal dominant pattern of inheritance may occur in some families (i.e., familial tremor). (Mov Disord 1988;13(1):5-10)Spasm: An involuntary contraction of a muscle or group of muscles. Spasms may involve SKELETAL MUSCLE or SMOOTH MUSCLE.Facial Muscles: Muscles of facial expression or mimetic muscles that include the numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. (From Stedman, 25th ed)Sensation Disorders: Disorders of the special senses (i.e., VISION; HEARING; TASTE; and SMELL) or somatosensory system (i.e., afferent components of the PERIPHERAL NERVOUS SYSTEM).Age of Onset: The age, developmental stage, or period of life at which a disease or the initial symptoms or manifestations of a disease appear in an individual.Dyskinesias: Abnormal involuntary movements which primarily affect the extremities, trunk, or jaw that occur as a manifestation of an underlying disease process. Conditions which feature recurrent or persistent episodes of dyskinesia as a primary manifestation of disease may be referred to as dyskinesia syndromes (see MOVEMENT DISORDERS). Dyskinesias are also a relatively common manifestation of BASAL GANGLIA DISEASES.Parkinsonian Disorders: A group of disorders which feature impaired motor control characterized by bradykinesia, MUSCLE RIGIDITY; TREMOR; and postural instability. Parkinsonian diseases are generally divided into primary parkinsonism (see PARKINSON DISEASE), secondary parkinsonism (see PARKINSON DISEASE, SECONDARY) and inherited forms. These conditions are associated with dysfunction of dopaminergic or closely related motor integration neuronal pathways in the BASAL GANGLIA.