Understanding Parkinson’s disease
The facts on Parkinson’s Disease

Parkinson's disease belongs to a group of conditions called motor system disorders. These are the result of the loss of dopamine-producing brain cells. The four primary symptoms of PD are tremor, or trembling in hands, arms, legs, jaw, and face; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance and coordination.
Patients may have difficulty walking, talking, or completing other simple tasks as these symptoms become more pronounced. PD usually affects people over the age of 50 and early symptoms of PD are subtle and occur gradually. The disease progresses more quickly for some people than in others. The shaking or tremor which affects the majority of PD patients may begin to interfere with daily activities as the disease progresses. 
Other symptoms may include depression and other emotional changes; difficulty in swallowing, chewing, and speaking; urinary problems or constipation; skin problems; and sleep disruptions.  There are currently no blood or laboratory tests that have been proven to help in diagnosing sporadic PD. The diagnosis is based on medical history and a neurological examination and can be difficult to be given with accuracy. Doctors may sometimes request brain scans or laboratory tests in order to rule out other diseases.
Treatment for Parkinson’s disease
Although there is no cure for PD at present, a variety of medications provide dramatic relief from the symptoms. Patients are given levodopa combined with carbidopa.  Carbidopa delays the conversion of levodopa into dopamine until it reaches the brain.  Nerve cells can use levodopa to make dopamine and refuel the brain's dwindling supply.  Although levodopa helps at least three-quarters of parkinsonian cases, not all symptoms respond equally to the drug. Bradykinesia and rigidity respond best, while tremor may be only marginally reduced. Problems with balance and other symptoms may not be alleviated at all.  Anticholinergics may help control tremor and rigidity.  Other drugs, such as bromocriptine, pramipexole, and ropinirole, mimic the role of dopamine in the brain, causing the neurons to react as they would to dopamine.  An antiviral drug, amantadine, also appears to reduce symptoms.  In May 2006, the FDA approved rasagiline to be used along with levodopa for patients with advanced PD or as a single-drug treatment for early PD. 
Surgery may be appropriate in some cases if the disease doesn't respond to drugs. A therapy called deep brain stimulation (DBS) has now been approved by the FDA for Parkinson’s disease treatment. In DBS, electrodes are implanted into the brain and connected to a small electrical device called a pulse generator that can be externally programmed. DBS can reduce the need for levodopa and related drugs, which in turn decreases the involuntary movements called dyskinesias that are a common side effect of levodopa. DBS requires careful programming of the stimulator device in order to work correctly. It also helps to alleviate fluctuations of symptoms and to reduce tremors, slowness of movements, and gait problems.