Bradykinesia is one of the most important symptoms in PD but may be hard to identify, especially in early stages.
Unlike tremor, bradykinesia is present in all cases of Parkinson's. While sometimes subtle, reduced arm swing, hesitation in initiating movement, micrographia, and reduced blink rate may be noticable and indicate the need for a focused motor exam. Hypomimia, hypophonia, and monotonous speech are also manifestations of bradykinesia. Bradykinesia can be mistaken for depression.
The frequency of dyskinesias in patients with young-onset PD is higher and could be 100% by 5 years of levodopa treatment.
Manuchair E., Pfeiffer R. Parkinson's Disease. Boca Raton, FL: CRC Press; 2005