I just realised that I have probably been suffering from the “curse of knowledge” when trying to explain Parkinson’s (PD) to people. With this I mean that things that are obvious to me are probably not as obvious to others when it comes to understanding Parkinson’s. Let me demonstrate with a few examples:
Biomarkers in Parkinson’s
I often say that there are no biomarkers in PD but if you read the scientific literature there are many examples. What’s up with that? The problem is that none of them are fully deterministic. With that I mean that none of them are relevant for all people with PD. Many different attempts at biomarkers are used in projects on PD and one example REM-sleep behaviour disorder or RBD. This condition entails people not lying still while sleeping but rather can thrash about in bed and if someone is sleeping next to them the spouse or partner might even get hurt. This is considered one of the early markers of PD in the scientific community but I would say that its usefulness to patients is limited. This is because not all people with RBD will go on to be diagnosed with PD and conversely not all people with PD will ever experience RBD. There are also other suggested prodromal signs like depression, loss of sense of smell etc. They are all equally non-deterministic as RBD and without clear patterns in co-occurences between different individuals who go on to be diagnosed with PD (or not).
Diagnosis of PD
Also here there are important challenges. The condition is generally diagnosed based on observations of a few key symptoms:
- Tremor. Not all PwP have this.
- Slowness of movement (bradykinesia). I would say that all PwP have this symptom but there are MANY other conditions that also give this symptom
- Stiffness (rigidity). Most PwP have this symptom in varying degrees but it can be difficult to distinguish from other conditions that result in stiffness.
Comparison with type 1 diabetes
Let me make a comparison with a different complex chronic condition: type 1 diabetes (T1d). There is a very distinctive and specific biomarker in blood glucose levels. All people with T1d need insulin to survive and they all use frequent blood sugar readings to regulate their treatment.
In short: both Parkinson’s and T1d are equal to being dealt a really shitty hand in the “poker game of life”. But while with T1d you get the two of clubs, seven of hearts, king of spades, ten of diamonds, and five of spades, with Parkinson’s your hand consists of an old bus ticket, a wrinkled up candy wrapper, your old business card from two re-organisations ago, a receipt from your latest visit to the pharmacy, and small piece of pocket lint…