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It’s 2 a.m. I am not awake because I want to be. I am awake because my leg hurts. So.. I spent the evening studying a word someone mentioned in a PM which I can’t believe I didn’t know.
What struck me most tonight was that, until a few hours ago, peripheral neuropathy wasn’t even a term I knew. Like many people living with PSP, I have become unexpectedly knowledgeable about neurology, movement disorders and medical research. Yet here I was, deep into the early hours, discovering an entirely new area of medicine because of a symptom I suspect I may be experiencing myself. The evening became a crash course in peripheral neuropathy and, at the same time, a reminder of the limitations of scientific research in rare diseases such as PSP.
The problem is not a lack of good researchers. The problem is numbers. PSP is frequently misdiagnosed, often for years. Fewer diagnosed patients means fewer patients available for research, and fewer patients available for research means studies built on samples of 9 or 23 people rather than hundreds. That reality does not invalidate the science, but it does remind us how much we still have to learn.
As for the symptom that sent me down this rabbit hole, it is not the ache of overdoing things, not a cramp and not an old sports injury. My ACL was removed and replaced years ago, so I know what those feel like. This feels different: deep, sharp, unpredictable and, at times, unbelievably painful. And then, just to make things more confusing, it sometimes disappears again. Whatever it is, it feels much more like nerve pain than anything else I have experienced, apart from a lumbar puncture six years ago that hit two nerves — an experience neither I nor my son, who heard me scream from outside the room, are likely to forget.
I turned to AI to help identify relevant papers and then, as I always do and strongly recommend others do, went back to the original studies myself. What I found surprised me. Two recent studies looking at peripheral neuropathy in PSP reached remarkably similar conclusions. The first, an Indian study, found evidence of peripheral neuropathy in 65.2% of 23 PSP patients. The second, a German study, found it in 66.7% of just 9 PSP patients.
For those unfamiliar with the term, as I was until earlier tonight, peripheral neuropathy is damage or dysfunction of the nerves outside the brain and spinal cord. It can cause burning pain, stabbing pain, electric-shock sensations, numbness, tingling, weakness and balance problems. Whether my own symptoms are caused by peripheral neuropathy, PSP itself, something else entirely, or a combination of factors, I cannot yet say.
What surprised me most was not the findings themselves but the sample sizes behind them.
Twenty-three patients.
Nine patients.
Perhaps this reveals my own ignorance, but before tonight I had assumed that meaningful medical studies were built on hundreds, perhaps thousands, of patients. I simply hadn’t appreciated the realities of researching a rare disease like PSP.
Suddenly those impressive percentages begin to look rather different.
Not because the science is bad, but because the challenge is so great.
This is not a criticism of the researchers. Recruiting patients for a rare disease like PSP is difficult and valuable work. In fact, the small sample sizes are part of the story. If patients spend years being misdiagnosed before receiving a PSP diagnosis, then there are inevitably fewer people available to take part in research. The result is that scientists are often forced to draw conclusions from numbers that would be considered tiny in many other fields of medicine.
At the same time, I cannot help wondering whether the patient community is its own uncounted sample. If two independent studies in two different countries both arrive at roughly the same conclusion, perhaps they are seeing something real. Maybe the true figure is 50%. Maybe it is 75%. Nobody knows yet. But it is probably not 0%.
What I do know is that people in PSP support groups have been talking about symptoms and sharing stories with me. Burning pain. Nerve pain. Odd sensations. Symptoms that do not always fit neatly into what many of us thought PSP was supposed to look like. A small formal study does not make a symptom unimportant. If anything, it suggests we should pay closer attention to what patients have been saying all along.
Tonight I am not a statistic. I have PSP, I have severe nerve-like pain in my leg and I know my own body well enough to know that something significant is happening. Have I been tested for every possible cause? No. Could there be another explanation? Absolutely. But while the literature debates studies involving 9 patients or 23 patients, I am sitting here as patient number one. One person. One experience. One data point. And that data point is telling me something important: the pain is real.
I have enormous respect for my neurologist, my GP and everyone else who cares for people like me. Sometimes the limits of medical knowledge are not about intelligence or effort. Sometimes they are about numbers. Too few diagnosed patients. Too few studies. Too little time. That is why awareness matters, why earlier diagnosis matters and why every patient’s story matters. Every person correctly diagnosed with PSP becomes part of the sample size.
Tonight, the scientists have studies of 9 and 23.
I have a study of one.
For readers interested in the science: the first study was “Comparison of Clinical and Electrophysiologic Characteristics of Peripheral Neuropathy in Progressive Supranuclear Palsy and Parkinson’s Disease” (2024), and the second was “Longitudinal Evaluation of Polyneuropathy in Atypical Parkinsonian Syndromes” (2026).