In this article, I aim to answer important questions regarding Parkinson’s disease and the associated dementia. While the
disease was identified and described over a century ago, we still have not as yet been able to ferret out its root cause,
notwithstanding the tremendous progress made in recent years. Like for many other diseases, it is believed to involve three
main causal components (inherited genetics, environmental influences, and, to a much lesser extent, lifestyle choices),
which collectively determine if someone will develop the disease. I will survey its signs, symptoms (motor and non-motor),
risks, and stages, distinguishing between the disease’s early- and late-onset. While discriminating between the disease and
its associated dementia, I will localize the latter within the broad spectrum of dementias. I will also describe what happens
to the brain as the disease takes hold and evolves. A number of medical conditions called Parkinsonisms may have one or
more of their signs and symptoms mimicking Parkinson’s. I will discuss them in some detail, including their five proposed
mechanisms (protein aggregation in Lewy bodies, disruption of autophagy, mitophagy, neuroinflammation, and breakdown
of the blood–brain barrier). I will further describe the approach to diagnosis, prediction, prevention, and prognosis. While
there is no cure and treatment for each affected person, motor symptoms are managed with several medications (Levodopa
always combined with a dopa decarboxylase inhibitor and sometimes also with a catechol-O-methyltransferase [COMT]
inhibitor, dopamine agonists, and monoamine oxidase-B [MAOB]-inhibitors) and eventually surgical therapy. Numerous
pharmaceutical agents are also available for individual non-motor symptoms (L-Dopa emulsions, non-ergot dopamine
agonists, cholinesterase inhibitors for dementia, modafinil for daytime sleepiness, and quetiapine for psychosis). Fortunately,
we can track the drug effectiveness with exosomes. Keeping in mind patients and their caregivers/partners, I will outline
available complementary therapies, palliative care, and rehabilitation, measures they can take beyond seeking standard
treatments, and supporting and advocating organizations at their disposal. Finally, I will survey promising new research
vistas in the field.
Key words: Dementia, environmental, genetics, lifestyle influences, motor and non-motor symptoms, Parkinsonism,
Parkinson’s disease