Scientists propose new theory of Parkinson's disease

Scientists propose new theory of Parkinson's disease

Catherine Paddock

As scientists delve deeper into the nature of Parkinson's, the more it appears that it is highly varied, suggesting numerous subtypes. A new review proposes that Parkinson's falls into one of two main categories, depending on whether it originates in the central nervous system (CNS) or the peripheral nervous system (PNS).

In addition to a strong link with RBD during the early phase, in the PNS-first subtype, the disease damages the autonomic PNS before it affects the brain's dopamine system.

In contrast, in the CNS-first subtype — which typically has no RBD in the early phase — the disease damages the dopamine system in the substantia nigra before it affects the autonomic PNS.

The autonomic PNS largely controls functions of the body that do not require conscious attention, such as digestion, breathing, heart rate, pupil dilation, and urination.

One area that appears to require further clarification is how the olfactory bulb, which is the organ in the nose that gives us our sense of smell, fits into the hypothesis.