While Parkinson’s disease (PD) and Multiple Sclerosis (MS) are both neurodegenerative disorders (i.e. entail cell death in some parts of the brain) that affect the central nervous system, they have some notable differences.
Firstly, the major site of deterioration in PD is more localized; the basal ganglia of the brain, which is responsible for modulating the body’s motor activity. This is why the majority of PD symptoms manifest in motor deficits (e.g. tremors and difficulties walking). MS has a more wide-spread effect on the body since the deteriorating structure is the myelin surrounding nerve fibres, which can be found in the brain, spinal cord, and the optic nerves. This is why symptoms vary in MS patients, depending on disease severity and location (e.g. vision problems and fatigue).
For more information on the differences (and similarites) of PD and MS use this link:
Image from: http://www.richardsonthebrain.com/central-nervous-system