The area in the brain that is the source of Parkinson's Disease is known as the substantia nigra. This is caused by the progressive impairment or deterioration of neurons.

Muscular: poor balance, stiff muscles, difficulty with bodily movements, muscle rigidity, problems with coordination, 

Speech: impaired voice, soft speech, or voice box spasms

Mood: anxiety or apathy

Nasal: distorted sense of smell or loss of smell

Urinary: dribbling of urine or leaking of urine
Tremor: can occur at rest, in the hands, limbs, or can be postural

Facial: jaw stiffness or reduced facial expression

There is one big difference between Embryonic stem cells and adult stem cells.  Embryonic cells can become all cell types of the body because they are able to give rise to several different cell types. However, Adult stem cells seems to be limited to different cell types of their tissue of origin. Another difference is Embryonic stem cells can be grown relatively easily while Adult stem cells are rare.