In this case study, we describe the symptoms, neurological examination, test results, and brain pathology of a man with Parkinson's disease (PD). PD commonly presents with tremor or changes in one's ability to walk or move. Other major difficulties caused by this disease include rigidity of the body, slowness of movement, and postural imbalance. The disease symptoms principally result from the degeneration of a specific population of neuronal cells in the brain stem, in a region called the pars compacta of the substantia nigra. Pathology shows the loss of these cells and the appearance of characteristic neuronal cytoplasmic inclusions called Lewy bodies, which are composed principally of aggregated α-synuclein protein.