brain, spinal cord, and nerve disorders
Tremor
Types of Tremors
Tremors can be Normal (physiologic) Abnormal (pathologic), caused by a disorder or drug Tremors are usually classified based on when they occur: Resting tremor:Occurring mainly at rest Action tremor:Occurring when a body part is moved voluntarily Action tremorsinclude Intention tremor:Triggered by movement toward a target (for example, reaching for a glass) Kinetic tremor:Appearing at the end of a movement toward a target or during any voluntary movement, such as moving the wrists up and down or closing and opening the eyes Postural tremor:Triggered by holding a limb outstretched in one position Tremors can also be classified by what causes them, as follows: Physiologic(the normal tremors that everyone has to some degree) Essential(a common hereditary disorder that rarely causes any other symptoms) Cerebellar(caused by damage to part of the brain called thecerebellum) Secondary(caused by a disorder or drug) Psychogenic(caused by psychologic factors) Other important characteristics of tremors are How fast the shaking is (frequency): Slow to fast How wide the movement is (amplitude): Fine to coarse How often the tremor occurs: Intermittent to constant How severe it is How rapidly it appears: Sudden to gradual Physiologic tremor is the normal tremor that everyone has to some degree. For example, most people's hands, when held outstretched, usually tremble slightly. Such slight, rapid tremor reflects the precise moment-by-moment control of muscles by nerves. In most people, the tremor is barely noticeable. However, a normal tremor may become more noticeable under certain conditions and may worry people. For example, the tremor may be more noticeable when people Feel stressed or anxious Are deprived of sleep Stop drinking alcohol or taking a sedative (such as a benzodiazepine) or an opioid Consumecaffeine (which are used to treat Drugs for Preventing and Treating Asthma and Have certain disorders, such as an overactive thyroid gland ( Hyperthyroidism ) that is causing other symptoms Essential tremor results from a problem in the nervous system, but people with this tremor rarely have any other symptoms of nervous system dysfunction ( Introduction to Symptoms of Brain, Spinal Cord, and Nerve Disorders ). The cause is unclear, but the tremor often runs in families. Essential tremor usually begins during early adulthood but can begin at any age. The tremor slowly becomes more noticeable as people age. Thus, it is sometimes incorrectly called senile tremor. The tremor usually involves the arms and hands and sometimes affects the head. When it affects the head, people may look as if they are nodding yes or shaking their head no. These tremors are usually worsened by holding a limb outstretched (against gravity) or by moving a limb. Usually, essential tremor remains mild. However, it can be troublesome and embarrassing. It can affect handwriting and make using utensils difficult. In some people, the tremor gradually worsens over time, eventually resulting in disability. Symptoms may resemble those of Parkinson Disease (PD) , and sometimes essential tremor is misdiagnosed as Parkinson disease. Rarely, people have Parkinson disease and essential tremor. Resting tremor occurs when muscles are at rest. An arm or a leg shakes even when a person is completely relaxed. The tremor becomes less noticeable or disappears when the person moves the affected muscles. Resting tremors are often slow and coarse. These tremors develop when nerve cells in the part of the brain called the basal ganglia are disturbed. The basal ganglia help initiate and smooth out intended (voluntary) muscle movements. Such disturbances usually result from Parkinson Disease (PD) or disorders that cause the same symptoms as Parkinson disease ( However, resting tremors can also result from use of drugs that can affect this part of the brain, such as antipsychotic drugs and some drugs used to relieve nausea. Resting tremors may be socially embarrassing, but because they go away when people try to do something (such as drinking a glass of water), they typically do not interfere with daily activities. This tremor occurs during a purposeful movement, as when reaching for an object with the hand. People may miss the object because of the tremor. Intention tremors worsen as people get closer to the targeted object. These tremors are relatively slow and wide (coarse). Intention tremors result from damage to the cerebellum, the part of the brain responsible for balance and coordination. Thus, cerebellar tremor and intention tremor may be used as synonyms. Common causes of intention tremor include Certain hereditary disorders that affect the cerebellum (called Spinocerebellar ataxias ) Multiple Sclerosis (MS) None Other disorders and drugs can also cause the cerebellum to malfunction, resulting in an intention tremor. They include Overview of Stroke None A Overview of Brain Tumors None Alcohol Use None Overuse of sedatives or antiseizure drugs Everyone has tremors to some degree. If the tremor is mild, some simple measures, such as holding objects close to the body, can make functioning easier. This type of tremor is most obvious when a limb is held in a position that requires resisting the pull of gravity, as when people hold their arms outstretched. The most common postural tremors are Essential tremor Physiologic (normal) tremor Complex tremor is a tremor that has features of more than one type of tremor. Common causes of complex tremors are Psychologic factors Widespread nerve damage such as that caused by Diabetes Mellitus (DM) or 