Longardner K, Bayram E, Litvan I Orthostatic Hypotension Is Associated With Cognitive Decline in Parkinson Disease. Front Neurol. 2020 Sep 2;11:897. doi: 10.3389/fneur.2020.00897. eCollection 2020.
McDonald C, Newton JL, Burn DJ Orthostatic hypotension and cognitive impairment in Parkinson's disease: Causation or association? Mov Disord. 2016 Jul;31(7):937-46. doi: 10.1002/mds.26632. Epub 2016 Apr 19.
Riley DE, Espay AJ Cognitive fluctuations in Parkinson's disease dementia: blood pressure lability as an underlying mechanism. J Clin Mov Disord. 2018 Feb 13;5:1. doi: 10.1186/s40734-018-0068-4. eCollection 2018.
Udow SJ, Robertson AD, MacIntosh BJ, Espay AJ, Rowe JB, Lang AE, Masellis M 'Under pressure': is there a link between orthostatic hypotension and cognitive impairment in alpha-synucleinopathies? J Neurol Neurosurg Psychiatry. 2016 Dec;87(12):1311-1321. doi: 10.1136/jnnp-2016-314123. Epub 2016 Sep 9.
Effects of Blood Pressure on Cognition and Cerebral Blood Flow in Parkinson Disease
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.