An important aspect of developing new potentially ‘curative’ treatments for Parkinson’s is our ability to accurately test and evaluate them. Our current methods of assessing Parkinson’s are basic at best (UPDRS and brain imaging), and if we do not improve our ability to measure Parkinson’s, many of those novel treatments will fail the clinical trial process and forever remain just “potentially” curative.
Blood pressure issues are a common feature of Parkinson’s that does not get a lot of attention, but new technology could provide us with new insight.
In today’s post, we look at new technology (under development) which could be applied to Parkinson’s, for the measuring and assessment of blood pressure, and we will look at how it could be used in certain clinical trials.
Apple watch 4 (not an endorsement). Source: NewScientist
Late last year, the tech giant Apple released yet more new versions of their phones and watches (with much fanfare). And before we continue: this is not an advertisement or endorsement (unless Apple wants to talk to me???… ).
Of interest was the new version of their watch, which has a handy feature of being able to tell you when you have fallen over (a warning that one was about to fall would surely be more useful, no?).
Useful feature, but those buttons are rather close for anyone with a tremor. Source: ATT
And much was made about the ability of the watch to monitor heart rate, which is a very clever trick, particularly for people with atrial fibrillation (periods of abnormal activity in the atrials of the heart) – although there appear to a few issues to be ironed out (Click here to read more about this).
Many of these smart watches and wrist band monitoring gadgets can now detect heart rate, but monitoring of blood pressure would actually be more useful for the Parkinson’s community.
What does blood pressure have to do with Parkinson’s?
During Super Bowl 51, ex-president George HW Bush was visibly wheel chair bound. He has in fact been using motorised scooters and wheelchairs since 2012.
His doctors have indicated that he suffers from Vascular Parkinsonism.
In today’s post we will discuss what Vascular Parkinsonism is and how it differs from Parkinson’s disease.
During a visit to the White house. Source: Heavy
An important concept to understand about the subject matter here:
Parkinsonism is a syndrome, while Parkinson’s is a disease.
A syndrome is a collection of symptoms that characterise a particular condition, while a disease is a pathophysiological response to internal or external factors. The term ‘Parkinsonism’ is an umbrella term that encompasses many conditions which share some of the symptoms of Parkinson’s disease.
There are many different types of Parkinsonism, such as:
- Idiopathic Parkinson’s disease (the most common type of parkinsonism)
- Progressive Supranuclear Palsy (PSP)
- Corticobasal Degeneration (CBD)
- Multiple System Atrophy (MSA)
- Essential tremor
- Vascular Parkinsonism
- Drug-induced Parkinsonism
- Dementia with Lewy bodies
- Inherited Parkinson’s disease
- Juvenile Parkinson’s disease
All of these conditions fall under the syndrome title of ‘Parkinsonism’, but are all considered distinct/separate diseases in themselves.
So what is Vascular Parkinsonism?
Vascular Parkinsonism was first described in 1929 by Dr Macdonald Critchley (King’s College Hospital, London).
Macdonald Critchley. Source: Npgprints
Title: Arteriosclerotic Parkinsonism.
Author: Critchley, M.
Journal: Brain (1929) 52, 23–83
PMID: N/A (this article is accessible by clicking here)
It is estimated that approximately 3% to 6% of all cases of Parkinsonism may have a vascular cause. Vascular (or Arteriosclerotic) Parkinsonism is results from a series of small strokes in the basal ganglia area of the brain and can lead to the appearance of symptoms that look like Parkinson’s disease: slow movements, tremors, difficulty walking, and rigidity.
Walking problems are particularly prominent with Vascular Parkinsonism, as the lower half of the body is usually more affected than the upper half. Another sign of Vascular Parkinsonism can be a poor or no response to L-dopa treatment, as production of dopamine is not the problem. Using brain scanning techniques we can see that some people with Vascular Parkinsonism will have a normal Dopamine transporter (DAT) scan – which demonstrates appropriate levels of dopamine being released and reabsorbed in the striatum (the red-white areas in the image below).
DAT-scan and MR images of 62-y-old male with Vascular Parkinsonism (A) and 62-y-old male with Parkinson’s disease (B). Source: JNM
The brain scans above are from a person with Vascular Parkinsonism (A) and another person with Parkinson’s disease (B). Firstly, note the reduced levels of red-white areas in the image (B) – this reduction is due to less dopamine is being released and reabsorbed in the striatum in Parkinson’s disease (as there are less dopamine fibres present). Compare that with the relatively normal levels of red-white areas in the image (A), indicating normal levels of dopamine turnover (suggesting dopamine fibres are still present). Next, look at the black and white image in panel (A) and you will see a red arrow pointing at damaged areas (darkened regions) of the striatum – indicative of mini strokes. A dopamine receptor scan may show a reduction in the levels of dopamine receptors as a result of the strokes, meaning that the released dopamine will not be having much effect.
Do we know what can cause the strokes associated with Vascular Parkinsonism?
The symptoms of Vascular Parkinsonism tend to appear suddenly and generally do not progress, unlike Parkinson’s disease. We don’t know for sure what causes the mini strokes associated with Vascular Parkinsonism, and it probably varies from person to person, In general, however, doctors believe that high blood pressure and diabetes are the most likely causal factors (heart disease may also play a role).
What does it all mean?
Some people of Parkinson’s disease may actually have Vascular Parkinsonism, which can result from mini strokes in the basal ganglia region of the brain. They will usually be unresponsive to L-dopa and have more motor issues with their lower half of the body.
While Ex-President George HW Bush’s situation is extremely unfortunate, it reminds us that not all forms of Parkinsonism are Parkinson’s disease – an important factor to keep in mind when considering treatment regimes. We have posted this information here to make the Parkinson’s community more aware of this form of Parkinsonism. Later in the year we will discuss another form of Parkinsonism.
The banner for today’s post was sourced from Ew