Parkinson's disease (PD) is the second most common neurodegenerative disorder and the fastest growing in the world, with a current global incidence of 10 million and 90,000 being diagnosed in the US each year - a rate that is only consistently increasing.
PD is characterized by impaired motor control alongside other nonmotor symptoms. Common characteristics of PD include:
- Difficultly in balance and coordination
- Rigidity
- Shaking or tremors
- 'Poker face' (facial rigidity)
Contrary to popular belief, PD is not exclusively associated with old age, with young-onset Parkinson's disease (YOPD) - occuring as young as 40 years old - being increasingly common.
One very common early symptom for PD is constipation, which affects 90% of PD patients and occurs up to 10 years before the common motor characteristics start to manifest. This nonmotor symptom highlights the popular hypothesis that PD begins in the gut.