PD is a chronically progressive, age-related, fatal neurological disease in humans described first by James Parkinson in 1817. Estimates indicate that 4 to 6 million people have been diagnosed with PD. It affects about 2% of the population at some time in life. The greatest prevalence occurs in the USA, with between 100 and 250 cases per 100,000 [315], placing PD as the 2nd most common neurodegenerative disease with an adult onset (after AD). Progressive resting tremor (4–7 Hz), rigidity, bradykinesia/akinesia, gait disturbance, and postural instability characterize PD clinically [316]. The disease progression is also associated with mood disturbances, dementia, sleep disturbances, and autonomic dysfunction [316]. There are currently no cures for PD. Medications and neurosurgery can relieve some of the symptoms.