Doubt? Not really. When PSP is diagnosed, it is nearly always right

Oddly enough the subject of Doubt has come up twice in the last 24 hours. A person with another serious neurological illness was feeling, perhaps oddly, a little calmer now that she had a diagnosis, and someone asked me whether it makes a difference to the average “Joe” that PSP and like diseases are not certain until autopsy.

Doubt has always been an issue for me, speaking candidly. When I was going through the journey of moving from a diagnosis that I thought was firm (PD, backed by two DATscans) to ‘it appears to be PSP’, to ‘possibly PSP’, to ‘probably PSP’, to ‘your diagnosis is PSP’, doubt gnaws at you. It is clearer now that I see the effects of PSP really taking place but in the earlier days it was really present and I spent far too much time worrying about it.

You get it both ways. You doubt yourself. Perhaps this is in the head (forgive the terrible pun), perhaps these symptoms are something else, despite the absolutely clear markers of vertical eye palsy, backwards balance and the rest. Should I push the button and destroy my career by retiring, as one example? Perhaps it is something else and this will go away. Please G-d.

And you get it the other way. You feel it from others. Maybe he is imagining it. Maybe it is not as serious as it seems. Maybe.

For some people of faith it makes little practical difference: ‘G-d will save me’ regardless of what the label says. I am not built that way, or perhaps I am not on that level. I believe that G-d has put me here for a reason I cannot fathom, and that I have to deal with what is actually in front of me.

For those like me, it is truly important to know what you are fighting.

Studies of patients with advanced cancer have found that a large proportion, in some studies around half, experience substantial distress specifically because of prognostic uncertainty, and that those distressed by uncertainty also report significantly poorer quality of life.

I concur.

So, finally, I did some research this morning, and some of the doubt has receded (feel free not to read on if you prefer doubt).

A 2017 study looked at 129 patients whose final diagnosis in life was PSP and who were later examined at autopsy. I say “final diagnosis in life” deliberately, because “confirmed” is precisely what a clinical diagnosis of PSP can never be. That is the whole point.

The results: 114 (88%) had PSP. 11 (9%) had one of CBD (corticobasal degeneration), MSA (multiple system atrophy) or frontotemporal lobar degeneration presenting as behavioural-variant frontotemporal dementia. 4 (3%) had Parkinson’s Disease. Not one of the 129 had something mild.

In terms of prognosis and average life expectancy, CBD, MSA and the frontotemporal cases actually have similar or slightly worse outcomes than PSP. Only the four with Parkinson’s drew the longer straw.

So the data seem pretty clear. Once PSP has become the final clinical diagnosis after specialist follow-up, it is usually right. In this study, nearly nine out of ten diagnoses were confirmed at autopsy.

I don’t want to dress this up. It is sobering. It speaks for itself and you can see the chart below.

One honest caveat: this was a brain-bank study, drawn from patients seen at specialist centres who donated their brains to research. The percentages are indicative rather than exact for the wider population. It was a large clinicopathological study, and I have not found later evidence that clearly contradicts the overall finding..

For those who want doubt, there is, I suppose, still room for it. And anyone of faith knows that all is ultimately in the Hands of G-d, whatever the statistics say.

But for those who are not good with doubt, the data is actually pretty clear.

I am not a scientist or a statistician. I am a patient blogging on PSP, and I know this question is out there, asked or not asked. It came up twice yesterday in my life, so there is simply no point avoiding it.

I have looked at other surveys, and whilst they don’t examine the question in the same way, they seem to be in tune with these findings. But if you know different, please let me know and I will correct.

Source: Respondek et al., “Which Ante Mortem Clinical Features Predict Progressive Supranuclear Palsy Pathology?”, Movement Disorders, 2017.