About 7 in 10 people with Parkinson first have a slight tremor in a hand or foot, according to the Parkinson Foundation. The tremor usually occurs when the muscles are at rest and relaxed. It usually appears on one side of the body. Later it may spread to the other side of the body, but to a lesser degree. Common symptoms as the disease gets worse include:

• Slowness of movement
• Rigid or stiff muscles
• A shuffling gait
• A stooped posture

Secondary symptoms include:

• Changes in speech
• Loss of facial expression (called "flat effect")
• Difficulty swallowing
• Drooling
• Dementia
• Sleep problems
• Depression
• Memory difficulties and slowed thinking
• Sexual dysfunction
• Fatigue and aching
• Urinary problems