What Is Parkinson’s Disease?

Parkinson’s disease (PD) is a common neurodegenerative disorder affecting middle-aged and elderly individuals, particularly those aged 65 years and older. Its hallmark symptoms include bradykinesia (slowness of movement), increased muscle tone (rigidity), postural instability, and resting tremor. But what exactly is Parkinson’s disease? Let’s explore this further.

What Is Parkinson’s Disease?

Parkinson’s disease—also known as paralysis agitans—is a relatively common neurodegenerative disorder. Its prevalence increases significantly among individuals aged 65 years and older, and symptom severity typically worsens progressively with advancing age.

Clinically, patients primarily present with resting tremor, rigidity, bradykinesia, and abnormalities in posture and gait. Resting tremor tends to intensify during periods of emotional stress but usually subsides during rest or sleep. In addition to motor symptoms, some patients also experience non-motor manifestations, such as sleep disturbances—including insomnia and vivid dreaming—and abnormal behaviors during rapid eye movement (REM) sleep.

What Factors Contribute to Parkinson’s Disease?

1. Genetic Factors

Approximately 5–10% of PD patients have a family history of the disease, with inheritance patterns including autosomal dominant or autosomal recessive transmission. However, the vast majority of cases are sporadic. The cytochrome P450 2D6 gene may represent one of several susceptibility genes associated with PD.

2. Environmental Factors

Over 80% of PD cases are sporadic. Environmental toxins play a significant role in disease pathogenesis. Exposure to certain environmental toxins—including paraquat, maneb, herbicides and insecticides, rotenone, and trichloroethylene—has been linked to an increased risk of developing PD. Conversely, smoking, tea consumption, caffeine intake, and elevated serum uric acid levels appear to be associated with a reduced risk of PD.

3. Aging-Related Factors

PD predominantly affects individuals over age 50. With advancing age, dopamine levels in the brain gradually decline. Clinical symptoms of PD typically emerge only when striatal dopamine content falls by more than 80%. Normal neuronal aging does not generally reach this threshold; thus, advanced age serves primarily as a predisposing or triggering factor rather than a direct cause.

The above provides an overview of what Parkinson’s disease is. We hope this information has been helpful.