parkinson's disease belongs to a group of conditions called movement disorders. the four main symptoms are: tremor or trembling in hands arms legs jaw or head. rigidity or stiffness of the limbs and trunk. bradykinesia or slowness of movement. postural instability or impaired balance. these symptoms usually begin gradually and worsen with time. as they become more pronounced patients may have difficulty walking talking or completing other simple tasks. not everyone with one or more of these symptoms has parkinson's disease as the symptoms sometimes appear in other diseases as well. parkinson's disease is both chronic meaning it persists over a long period of time and progressive meaning its symptoms grow worse over time. it is not contagious. although some parkinson's disease cases appear to be hereditary and a few can be traced to specific genetic mutations most cases are sporadic -- that is the disease does not seem to run in families. many researchers now believe that parkinson's disease results from a combination of genetic susceptibility and exposure to one or more environmental factors that trigger the disease. parkinson's disease is the most common form of parkinsonism the name for a group of disorders with similar features and symptoms. parkinson's disease is also called primary parkinsonism or idiopathic parkinson's disease. the term idiopathic means a disorder for which no cause has yet been found. while most forms of parkinsonism are idiopathic there are some cases where the cause is known or suspected or where the symptoms result from another disorder. for example parkinsonism may result from changes in the brain's blood vessels.
what is parkinson's disease?