Parkinson’s disease is a disease of the nervous system in which patients lose control of body movement.  Clumsiness, slowed movements, being off balance and shaking can be the result of the loss of certain cells in the brain.  Past studies have shown that the combination of the two drugs, levodopa and carbidopa, can be highly effective in easing the symptoms of Parkinson’s disease.  Levodopa-carbidopa regimens are typically taken orally (by mouth).  However, after continuous use of oral levodopa-carbidopa, over a long period of time, it may not work as well. Levodopa is used in the body in such a way that it reduces Parkinson’s Disease symptoms. Carbidopa is added to improve the effect and reduce the undesirable effects of levodopa. This study will examine these drugs in a gel form.  The gel will be delivered to your small intestine through a catheter (tube) surgically inserted by a special extension tube (called a PEG-J tube) passing through your stomach.  The levodopa-carbidopa intestinal gel cassette reservoir will be connected to a portable pump which continuously pumps the gel into your intestine. The goal of delivering the gel directly into your small intestine is to provide the gel more consistently than currently available levodopa/carbidopa, so it may possibly control the Parkinson’s disease symptoms.