The second brain in Parkinson's disease: fact or fantasy?

Parkinson's disease (PD) is a movement disorder characterized by reduced dopamine levels due to degeneration of the substantia nigra. The clinical presentation is underlined by bradykinesia, postural instability, and tremors. PD is the second most common neurodegenerative disease worldwide, with a huge monetary burden. In the United States alone, it is estimated that in 2017, the total economic cost was $51.9 billion, and projected to surpass $79 billion by 2037. Extensive research has been conducted into the pathophysiology and clinical implications of the disease. Within neurodegenerative disorder itself, the entity involving the brain-gut axis has been a fundamental model in understanding the disease process. More so than ever in PD, the association between gut health and neurological disease is gaining momentum, with the fascinating idea of influencing neurological health by treating the gut.