7/14/2023
One of the benefits of being a Professor Emeritus is that the job comes, at least at Rutgers, with free access to the scientific literature. The title ‘Emeritus’ seems august but the fact is that if offers few perks. For example, I don’t get paid, and the University doesn’t provide an office (although, since I’m in Texas, an office wouldn’t be of much use anyway). But I often need to read scientific articles. And without university affiliation, they’re expensive, often costing more than $50 per article. The journals allow you to look at an abstract of an article that you might be interested in, but don’t allow access to the full text. Often that means that the contents aren’t really pertinent to the subject that I’m investigating, resulting in a waste of my money.
All is is preface to the fact that I’ve been looking for a good scientific review article on Parkinson’s. Many of the ones that I’ve examined are directed at non-scientists who have the disease. I’ve saught to find one that is more technical. For that I’ve turned to Google Scholar and used it to search through scientific and medical journals. In this post, I’ll go over some insights that I’ve gleaned from an article that I’ve located in the journal Lancet, a prestigious British publication.
The article is by Bastiaan R. Bloem, Michael S Okun, and Christine Klein and is in Lancet 397: 2284–303 (2021). I’ll try to summarize some of its more salient points, some that haven’t been emphasized in the popular literature.
The first point the authors make is that the prevalence of Parkinson’s disease is increasing. They state that “Parkinson’s disease might even be the fastest growing neurological condition worldwide.” Part of reason for this increase is that people are living longer, and Parkinson’s is a disease of the elderly. In addition, the medical community is more aware of the disease’s symptoms and diagnosis is more accurate. But even after taking age and diagnostic accuracy into account, the incidence of Parkinson’s seems to rising more than other neurological diseases. Why? No one knows.
A second point that I haven’t seen emphasized has to do with the variation in the disease. “Various observations suggest that Parkinson’s disease might not exist as a single entity.” Moreover, “,,, every person has their own unique Parkinson’s disease. …, an extreme notion would be to say that there are over 6 million different variations of Parkinson’s disease in the world.” The authors point out that this variation has important implications, including the need for personalized care and individualized treatments.
Then there’s the question of diagnosis. “Up to 20% of people with Parkinson’s disease do not have a tremor; however, bradykinesia [slow movement] is always present.” I didn’t know that.The article emphasizes that diagnostic errors are common. “In clinical trials of early-stage Parkinson’s disease, up to 15% of people with the disease are diagnosed incorrectly.”
I had never heard the word ‘prodromal’. It’s a medical term for symptoms that occur before the onset of the clinical phase of disease. With regard to Parkinson’s, constipation is a common prodromal symptom. The symptom most predictive of Parkinson’s, the authors conclude, is REM-based sleep disorder. According to the Mayo Clinic’s website, “Rapid eye movement (REM) sleep behavior disorder is a sleep disorder in which you physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM sleep — sometimes called dream-enacting behavior.” I’ve had two of these episodes, both occurring before I was diagnosed with Parkinson’s.
The article also addresses therapy. Their analysis of the literature indicates that there is wide variation in reaction to levodopa therapy among people with Parkinson’s. Some people become resistant to the treatment. One possible explanation is that intestinal bacteria may harbor DOPA decarboxylase enzymes, converting DOPA into dopamine before it reaches the brain. For those people, an alternative route of administration of the drug might be helpful. For example,CVT–301, a self- administered levodopa oral inhalation powder, has been shown to improve symptoms in a clinical study.
My interest was centered on the final issue that the article addressed: slowing down progression of the disease through drug intervention. They mention several drugs that have been repurposed, that is, agents directed at other diseases but under investigation for Parkinson’s therapy. The cough suppressant, ambroxol, for example is being tested in clinical trials. I found an article on the drug terazosin, used to treat benign prostate hypertrophy, that may have some modest effect on Parkinson’s. I’ve begun using the drug myself.
Here is the article’s conclusion:
Parkinson’s disease has been recognized for over 200 years. Together, the various forms of Parkinson’s disease create fast-growing health-care issues with enormous global impact. Fortunately, Parkinson’s disease is treatable, particularly when the interventions are delivered with a personalised approach, and by well trained experts.