Parkinson’s disease is a progressive neurodegenerative disease that, over many years leads to impairment in movement and deficits in mental functioning. This is one of the most common nervous system disorders in the elderly population. Parkinson’s disease is caused by the degeneration of dopamine-producing neurons in the midbrain. The function of these cells is to regulate movement. Their degeneration leads to muscle rigidity and bradykinesia, which are characteristics of the disease.