The primary symptoms of Parkinson’s disease are all related to voluntary and involuntary motor function and usually start on one side of the body. Symptoms are mild at first and will progress over time. Some individuals are more affected than others are. Studies have shown that by the time that primary symptoms appear, individuals with Parkinson’s disease will have lost 60% to 80% or more of the dopamine-producing cells in the brain. Characteristic motor symptoms include the following:
- Tremors: Trembling in fingers, hands, arms, feet, legs, jaw, or head. Tremors most often occur while the individual is resting, but not while involved in a task. Tremors may worsen when an individual is excited, tired, or stressed.
- Rigidity: Stiffness of the limbs and trunk, which may increase during movement. Rigidity may produce muscle aches and pain. Loss of fine hand movements can lead to cramped handwriting (micrographia) and may make eating difficult.
- Bradykinesia: Slowness of voluntary movement. Over time, it may become difficult to initiate movement and to complete movement. Bradykinesia together with stiffness can also affect the facial muscles and result in an expressionless, “mask-like” appearance.
- Postural instability: Impaired or lost reflexes can make it difficult to adjust posture to maintain balance. Postural instability may lead to falls.
- Parkinsonian gait: Individuals with more progressive Parkinson’s disease develop a distinctive shuffling walk with a stooped position and a diminished or absent arm swing. It may become difficult to start walking and to make turns. Individuals may freeze in mid-stride and appear to fall forward while walking.
Secondary symptoms of Parkinson’s disease
While the main symptoms of Parkinson’s disease are movement-related, progressive loss of muscle control and continued damage to the brain can lead to secondary symptoms. These vary in severity, and not every individual will experience all of them. Some of the secondary symptoms include:
- anxiety, insecurity, and stress
- confusion, memory loss, and dementia (more common in elderly individuals)
- difficulty swallowing and excessive salivation
- diminished sense of smell
- increased sweating
- male erectile dysfunction
- skin problems
- slowed, quieter speech, and monotone voice
- urinary frequency/urgency