What defines dystonia in the context of movement disorders?

Dystonia is characterized primarily by abnormal muscle tone, which manifests as sustained muscle contractions, abnormal postures, and twisting movements. This condition can impact various muscle groups, leading to an unusual posture or involuntary movements that can be painful or cause discomfort. The abnormal muscle tone distinguishes dystonia from other movement disorders that might involve involuntary muscle contractions or loss of coordination.

The focus on abnormal muscle tone is key to understanding dystonia, as it is not purely about involuntary movements (though they can occur) but rather about the way that muscle tension is disrupted. This can result in hypertonia, where muscles are excessively tight, or hypotonia, where there is reduced muscle tone, leading to a range of clinical presentations.

While involuntary muscle contractions can be associated with dystonia, they are not exclusive to it, as other conditions can also cause similar symptoms. Extreme fatigue and loss of coordination are not defining features of dystonia but are more commonly linked to other movement disorders or neurological conditions. Thus, recognizing the central role of abnormal muscle tone is essential for accurately identifying and understanding dystonia within the landscape of movement disorders.