Tremors might become worse when the patient is relaxed or under stress, but often diminish while the patient is sleeping. These tremors can make it difficult to hold a utensil at meals, read the newspaper, or perform other daily activities. Interestingly, a few seconds after a patient places his hands on a table, the shaking is most pronounced. The shaking can be decreased by intentional movement. Rigidity or resistance to movement develops in many Parkinson's patients.
Rigidity is caused by a patient's muscles being continuously contracted.
Two muscle groups are generally required to work together to create motion. One muscle group is relaxed, while the other is contracted. Since both muscle groups are contracted during rigidity, no movement occurs. Since the muscles are always working or contracted, the patient's muscles might ache and feel stiff. Rigidity can also cause the patient's face to look emotionless.