The shortage of dopamine results in diminished control of the muscles. The first sign of Parkinson's is usually a tremor of an arm or leg on one side of the body. In time, the tremor spreads to the other side of the body, and may eventually affect the jaw, neck, and tongue. Weakness, a stiff neck and back, and tight muscles are other early warning signs, although they could just as easily have nothing to do with Parkinson's. As the disease progresses, movement becomes slower.
People find that motions are hard to start, difficult to control, and a challenge to complete.
Muscles become stiffer than usual. Tightness in the back and neck may force the victim to stoop. Rigid facial muscles produce a blank, staring appearance. Gestures get jerky. Walking turns into a shuffle.