A body tremor is an uncontrollable muscle contraction that causes shaking or twitching. Body tremors can affect an isolated part of the body, or sometimes they can spread to multiple parts of the body. The condition can be caused by a number of underlying factors, from simple lack of sleep to a more serious medical disorder such as Parkinson's disease.
The involuntary back-and-forth movement associated with body tremors is known as oscillation. The onset and duration of such tremors can vary, although the movement is usually rhythmic in nature. While the hands are the most common source of oscillations, just about any part of the body can be affected, including the face, legs, head, and even the vocal cords.
The classification of body tremors exists under four main types, with various subtypes. Each classification is made based on when the muscle contractions are most severe. For example, intention tremors are so named because they are most severe when the affected individual is making any type of intentional movement. These types of tremors produce slow, expanding oscillations. They are caused by damage to the cerebellum of the brain from strokes, tumors, or degenerative disorders, and are therefore also known as cerebellar tremors.
Resting tremors are those contractions at their worst when the body is at rest. The main subtype of tremors at rest is parkinsonian tremor. It is so named because this contraction frequently signals the development of Parkinson's disease. Caused by brain damage, parkinsonian tremor is often concentrated in one hand or limb and eventually moves to the other side of the body. Drug-related tremors also typically manifest as tremors at rest.
A third type of body tremors occurs when parts of the body are tense and contracted. Contraction tremors are generated from the body's response to certain stimuli and therefore consist primarily of physiological tremors. Stress, fever, exhaustion, alcohol withdrawal, and hunger can all cause body tremors, and as such, treating the root cause usually clears up the condition. Physiological tremors may not even be visible to a casual observer.
The last type of body tremors (postural tremors) occur when an individual is in a postulated position against gravity, such as when the arm is raised. Postural tremors consist of some physiological tremors and a subtype called essential tremors. For the most part, essential tremors have many of the same causes and characteristics as physiological tremors. Essential tremors have some important variations, including their initial mildness, their progression in severity over time, their attacks in middle-aged individuals, their concentration on one side of the body in the head or hands, and their possible heritability. Essential tremors are also the most common type of tremor.
The total number of body tremor subclassifications is about 20. An additional possible condition is dystonic tremor, characterized by twisting and repetitive movements associated with the movement disorder dystonia. Another condition is discernible by its effect of cramps and tremors in the legs: orthostatic tremor. Even psychiatric disorders can cause psychogenic tremor, which has a rapid and sudden onset and disappearance. When an individual's midbrain is injured, rubral tremors, which produce slow and persistent involuntary movements, can occur.
Despite the different types, body tremors have several points in common. For one thing, they are more likely to occur in people who are over the age of 50. However, there are no significant differences between the number of men and women who may develop the condition. Certain side effects are also frequently associated with body tremors, especially a trembling voice and difficulty with fine motor movements such as writing or holding utensils.
A visit to the hospital can better determine the type, cause, and possible treatment for body tremors. Reflex and sensory tests may be done, and a detailed family history will likely be done. The doctor may also perform neurological tests to determine if an underlying brain injury or disorder can be discovered. Treatment depends on the root cause and can be as simple as removing the stimulus triggers. In severe cases, the recommended course of action may involve a more complex procedure such as surgery.