during a desired movement. It may occur in situations where the individual's motor intention spreads to either nearby or distant muscles, taking away from the original goal of the movement. Overflow is often associated with dystonic movements and may be due to a poor focusing of muscle activity and inability to suppress unwanted muscle movement. Co-contraction refers to a voluntary movement performed to suppress the involuntary movement, such as forcing one's wrist toward the body to stop it from involuntarily moving away from the body. In evaluating these signs and symptoms, one must consider the frequency of repetition, whether or not the movements can be suppressed voluntarily (either by cognitive decisions, restraint, or sensory tricks), the awareness of the affected individual during the movement events, any urges to make the movements, and if the affected individual feels rewarded after having completed the movement. The context of the movement should also be noted; this means that a movement could be triggered in a certain posture, while at rest, during action, or during a specific task. The movement's quality can also be described in observing whether or not the movement can be categorized as a normal movement by an unaffected individual, or one that is not normally made on a daily basis by unaffected individuals. Differential diagnosis Diseases that feature one or more hyperkinetic movements as prominent symptoms include: Huntington's disease Hyperkinesia, more specifically chorea, is the hallmark symptom of Huntington's disease, formerly referred to as Huntington's chorea. Appropriately, chorea is derived from the Greek word, khoros, meaning "dance." The extent of the hyperkinesia exhibited in the disease can vary from solely the little finger to the entire body, resembling purposeful movements but occurring involuntarily. In children, rigidity and seizures are also symptoms. Other hyperkinetic symptoms include: Head turning to shift eye position Facial movements, including grimaces Slow, uncontrolled movements Quick, sudden, sometimes wild jerking movements of the arms, legs, face, and other body parts Unsteady gait Abnormal reflexes "prancing," or a wide walk The disease is characterized further by the gradual onset of defects in behavior and cognition, including dementia and speech impediments, beginning in the fourth or fifth decades of life. Death usually occurs within 10–20 years after a progressive worsening of symptoms. Caused by the Huntington gene, the disease eventually contributes to selective atrophy of the Caudate nucleus and Putamen, especially of GABAergic and acetylcholinergic neurons, with some additional