Society has developed an insatiable thirst to turn everything into data. And for good reason, big data analytics has revolutionized everything from radiology to basketball. The overwhelming success has led many to believe that if we just gather enough information and apply clever enough algorithms we can come up with more effective solutions to just about any problem we face.
This belief has spilled over into healthcare and driven the creation of a wide variety of devices designed to turn some aspect of health or disease into data. In Parkinson’s this has resulted in fingernail sensors, eye trackers, full body 3D motion sensors, and much more.
But, can something as subjective as Parkinson’s disease can be turned into meaningful data? Given how incredibly heterogenous and multifaceted the disease is, can any objective measure capture enough of the experience to inform therapeutic decisions and improve outcomes, or will we just end up with piles of data and no real world benefits for patients?
(In case you can’t tell, I’m skeptical. To give some idea as to why I have my doubts, scroll below to find my descriptions of some of the cardinal symptoms of PD and why I think they are so difficult to capture.)
Last month the Journal of Parkinson’s released a series of incredibly insightful articles from many of the world leaders in PD predicting what the next 20 years will look like for Parkinson’s. Several touched on the emerging role of tech in PD, but the one that stood out to me was a paper from Prof. Anthony E. Lang and Prof. Alberto Espay. Among many thought-provoking assertions the author’s note: “Big data may be 99% irrelevant”, “Big data will not be used to find order in complexity but to confirm or refine what we already know.”
While I agree, I would add that there is an opportunity to make some of these attempts useful, but it would require flipping the equation used to design and develop these technologies on its head.
Almost all devices for Parkinson’s are designed to capture data relevant to clinicians. Just look at the language used in papers on the topic from the Movement Disorder Society, a body which sets the best practices in the field. Every technology is gauged by its clinical relevance. While understandable from the point of view of clinicians, it overlooks the fact that the vast majority of trials and treatment strategies do not happen within the purview of the clinic.
Every single day patients run experiments: they eat different foods, get varying amounts of exercise, take medication at slightly different times, and much more. Many of these adjustments have some impact on ones disease, but they are extremely difficult to track and objectively measure. Maybe if these products were designed like everything else on the market, with the end user in mind first, focusing on the first-person subjective experience rather than third-person observations, we might have a more effective suite of tools at our disposal.
This was summed up well by Sara Riggare, PhD student at the Karolinska Institute: “The key is to find ways to measure things that help people make meaningful choices on issues important to them. Currently the frenzy is to market products measuring things easy to measure, regardless of if it helps people or not.”
But getting there would require a radical redesign to how we deliver healthcare, a shift to a system focused on empowering patients to make their own decisions about their health. There are some groups advocating for this, like PCORI, the patient-centered outcomes research institute, but what we would really need is an entire healthcare system centered on the patient rather than the doctor, as well as a much more nuanced understanding of what patients experience.
The Subjective Experience
Below are my descriptions of what the cardinal motor symptoms of Parkinson’s feel like. None of the medical definitions I have read do them justice. Seeing them also often distorts ones understanding because they look very different from how they feel. Keep in mind that these are very difficult things to put into words, kind of like trying to explain what a cold feels like to someone who has never been sick. Also I have only described some of the motor symptoms of PD, they are the low hanging fruit, the non-motor symptoms are a whole other phenomenon that I’m not going to attempt right now.
On/Off – Before I can explain the symptoms I have to start with the On/Off phenomenon. In many ways this is a measure of how responsive one is to levodopa as some patients have very pronounced differences, and others can barely tell if their medication is On or Off. I get about four to five transitions from On to Off and vice-versa throughout the day. Most On periods last roughly an hour and a half before anywhere from a 5 to 30 minute transition to Off. It is during the transition to Off that I feel best, however during this transition I can feel the energy and control slowly dissipating from the tips of my fingers and up through my limbs. I think what I feel is the lack of sensation in my neuromuscular junctions as they gradually lose connectivity, impairing my ability to contract corresponding muscles. I switch On suddenly, feeling it first in my fingers and toes. I usually wriggle them free for a second then get a slight high feeling the drug wash over the rest of me. When I’m On, I’m anxious to get things done and energized by the mobility I feel throughout my limbs (as well as by the flood of dopamine throughout my brain.) The first three symptoms described below are generally felt during Off times, the last during On times. Also everything is more pronounced on my right side by a factor of two or three.
Bradykinesia/Rigidity – Bradykinesia is classically defined as a slowing down and loss of spontaneous and voluntary movement. It is often described as a separate symptom from rigidity, but for me it is very difficult to tell where one ends and the other begins. During these times my body still responds and does what I want it to do, but without the same ease and fluidity as when I am On. Everything is more mechanical as fine motor skills lag and I lose dexterity in my fingers, where I feel it most acutely. It is kind of like being stuck in the mud, but that implies an external force, imagine if you will something internal, almost like mud caked between your muscles and your bones. You could think of it like gears without oil, but instead of a grinding of parts its more like a lack of power to drive them. Another analogy I often hear is adding weights, but that implies working against gravity, this an entirely different sensation as you are working against an internal force rather than anything external.
Tremor – The most easily recognizable of symptoms. There are two kinds, a resting tremor and an action tremor. Resting tremor is experienced most when Off, action tremor when On. The best analogy I can think of for resting tremor is like a kite on a tether that loses some connectivity at the end but stays attached and starts flapping in the wind, except if the wind were a reverberating force through the string rather than an outside force. There are a lot of weird tremor phenomenon, like when I cross my legs the tremor travels from one foot to the other, or if I stand up it can move to my hands. I can almost feel the electricity going up one limp and down the other. It’s kind of cool actually, I can feel the networks of my nervous system.
Dystonia – I only get it occasionally in my feet, I can’t imagine what it is like in other body parts. It tends to feel like someone has tied a string to your toes and pulled them towards the heel and then tied the string around your ankle. Yet, if I pull on the muscles in my shin and thighs in just the right way the string releases and the foot uncurls. Go figure.
While the symptoms described above seem distinct, they often feel like an overlapping phenomenon. Additionally I think proprioception is also affected. At times when I close my eyes and concentrate it can be hard to pinpoint where my limbs are.
Dyskinesia – This might be the most difficult of them all to explain. It only happens during peak On times and is characterized by a writhing wave-like motion. It feels as though there are too many signals being switched on at once and the electricity jumps uncontrollably around my body. My right shoulder elevates slightly, my right arm and leg are difficult to control in space, and my right foot kicks out ahead of me when I walk. I also find it hard to accurately control the amount of pressure I can apply, a lot or very little are fine, but anything in between is tricky. If I hook my foot around something like the leg of a chair it can temporarily stop the motions.
Well, there you go, hopefully this gives a little clarity as to what the lived experience is like and also why it is so difficult to measure. I’m also hoping there is somebody out there clever enough to figure out how to actually turn what I describe into meaningful data. One important point to keep in mind that adds a whole other layer of complexity is that this is just how each symptom feels to me, I’m sure they feel different to others. For another perspective check out the graph below describing On/Off fluctuations and their accompanying symptoms from David Sangster, patient advocate and ambassador to the World Parkinson Congress for Kyoto 2019.
To any other people with PD, I’d love to hear your descriptions of what your PD feels like in the comments below or you can message me here.