Motor Symptoms

Image from NIEHS, NIHThe definitive motor symptoms of PD are:

• Tremor (resting tremor most common in the jaw, hands, and legs, and action or postural tremor)
• Bradykinesia
• Rigidity, both appendicular (in the extremities) and axial (in the neck and trunk)
• Postural instability (retropulsion or tendency to fall backward most common)

It has been estimated that these symptoms do not typically reach diagnostic criteria until there has been a loss of approximately 80% of dopaminergic function in the striatum. Additional motor symptoms include start hesitation, decreased dexterity and hypomimia (masked face). Other inherent symptoms include bulbar symptoms such as dysphagia (problems swallowing), sialorrhea (drooling), dysarthia (slurred speech) and hypophonia (problems with voice production).

Most PD-specific therapeutics now in use are designed to treat motor symptoms. Deep brain stimulation has also proved effective for the motor symptoms of PD.