The cardinal signs of PD are the primary motor symptoms:Shaking or tremorSlowness of movement, called_bradykinesiaStiffness or rigidity of the arms, legs or trunkTrouble with balance and possible falls, also called postural instabilityIt is important to know that there are many other possible symptoms that are called secondary motor symptoms and nonmotor symptoms. In the past, it was generally thought that the primary motor symptoms are the most troubling for PD patients. However, in recent years it has been recognized that for many patients, nonmotor symptoms such as cognition issues, fatigue, constipation, and sleep problems can be the most troubling.