The first symptom of PD is often a tremor, typically manifested in one hand. Generally, one side of the body is affected before the condition becomes bi-lateral. Rigidity is often associated with PD. With rigidity, the flow of a walking gait becomes a shuffle and facial expressions may be reduced. Bradykinesia is often present being marked by slowness in movement. Bradykinesia can affect the simplest of tasks, such as walking across a room or reaching for a glass of water. Postural instability may occur with PD. In this case support mechanisms may be appropriate, such as a cane, a walker or other device.

As PD is a progressive disease, these symptoms become more pronounced. Walking, talking, or completing other simple tasks become more difficult. In more progressive stages, assistance is needed to perform daily functions. Secondary symptoms may include sleep disturbances, personality changes, depression, sexual difficulties, speech impairments, and dementia.