United Kingdom: Dr Suzanne O’Sullivan (BPS neurologist)

In the rubber hand illusion, as in other illusions, the illusory sensation is almost immediately extinguished as the brain corrects its momentary error. The initial conditioning doesn't cause the participant to go on believing that the rubber hand is their own. You could just as well argue that it's a good demonstration that 'beliefs' don't cause 'symptoms' that are anything other than superficial and temporary.

 

Pain is in the brain in the sense that the event of experiencing pain must be an event in the brain rather than in the knee or stomach if what we know about neurobiology is roughly right. Signals come from the knee along nerve axons that are a bit like electric wires and arrive in the brain. (They may get blocked on the way in the spinal ganglia or cord.) Having got to the brain the signals are collated with other signals and if the pattern is right somewhere in the brain a final signal is received that 'feels painful' to one or more nerve cells. (This bit gets complicated but let us just say that somewhere in the brain a final signal is sensed as painful.)

Pain reprocessing presumably is designed to influence the other signals that get collated with the pain from the pain receptor in the knee, which might amplify or inhibit the final signal that is felt as pain.

The rubber hand illusion demonstrates that you can get the brain to collate signals wrongly if you provide it with a really confusing input. But I don''t see that that has much to do with the way we feel pain when we have a bad knee.

Does that make sense?

 

Would that potentially be an argument against the generalisability of the findings from mirror therapy for phantom pain because nerve signals from the stump of a limb is probably pretty confusing?

 

I can make it "make sense"… I may have to think on it for a while. It seems that in the rubber hand illusion could apply to tactile allodynia in that the pain signal might be reprocessed as a simple touch and not painful? Or am I missing something?

 

Hard to say but for phantom limb pain it will be the signals from the pain nerves themselves that are out of line. In the rubber hand it is the contextual signals that are wrong .

 

Maybe it could. But I am thinking that conflicting signals tend to amplify pain - if you are not expecting a small nip it is likely to feel much worse than if you know it is just a benign experiment and of course if you do the nipping yourself it tends to be least. To reduce pain in a disease state you might need to make associated signals less conflicting but it is not very obvious how you could do that. I sense something a bit like Mark Edwards's topsy turvy theory for functional neurological disorders.

 

Jonathan, does any of this apply to "referred pain"? How does it occur?

 

I don't think this applies to referred pain.

Referred pain is pain from a body site A which is normally felt at site B, for reasons th I don't think we understand too well. Pain from the shoulder joint is felt on the outside of the upper arm. Pain from the gallbladder can be felt in the right shoulder tip. Heart pain often goes down the left arm.

I don't know of ways to change these patterns, although it is possible that there are.

Referred pain is often confused with nerve compression pain, which is felt somewhere else for a different reason. If a nerve that brings sensations in from part G is trapped at point H the pain is felt at G. So sciatica is pain in the foot, calf or leg due to trapping of a nerve root feeding those parts within the spine by a disc. Pain from the disc itself is referred often to the thigh or back of calf so you quite often get a mixture of referred and root compression pain.

 

Don’t certain religions cure you, if you pay, sorry pray hard enough? Is that the same as what the nice neurologist is proposing?

 

In medieval Europe, you used to be able to buy what was essentially salvation. Some would say it was not endorsed by the central religious governing bodies, but it became so widespread that it in practice was.

Nowadays, we have the likes of televangelists.

 

Yes, I bet the BPS would think themselves superior yet they’re basically the same. Believe you are better and you are better.

 

Her general thought world is is

Start with no precise definition of chronic Lyme. Criticise the concept as having no precise definition but do not take up any challenges (e.g. does untreated Lyme become chronic and if it has become chronic does it exist or not?) A bit wry but not a trick question. Ignore in any case as ,shall we say, "vexatious".

Then

1st Assert that Lyme is being misdiagnosed (which imo is probably true with treatments that may be dangerous. Start with a truth. get 'em onside. Compassionate and concerned. Nice.

2nd Imply on this basis that chronic Lyme diagnoses are invalid. Don;t engae with the possibilty that some are valid and essential.

3 Keep in mind (her mind) that even if it existed there is no benefit to the diagnosis as effective treatments do not exist

2 and 3 to be done mainly by ignoring any counter evidence

4 Assert that treatment is dangerous but do not mention that failure to treat may be even more ruinous

5 Talk as if Lyme were the only difficult to diagnose condition and as if less than 100% certainty is unacceptable because it is dangerous to treat , the treatments do not work and failure of treatment indicates not a medical learning curve but the wrong diagnosis. Again don't mention the downside of missed diagnosis or any contrary evidence. Appoint yourself as chief diagnostic artist so that those who after careful assessment of bloods, history, exclusions diagnose Lyme may be seen as second rate scrawlers or even draughtsmen but not true artists.

6 Do talk about art at some point. Always a winner in some circles. No question as to who the artists are. Remember you are painting a picture anyway. Broad brush or impressionist. Not fine detail about numbers who have had chronic Lyme or novel abx, but general impression. As per above fine detail is for draughtsmen not artists.

7 Talk about unfortunate people who hold on to illness identity etc. They need compassion and it is only compassionate to deny those with genuine chronic Lyme a diagnosis as they can't be helped anyway. It's all about compassion.(ignore any cases of improvement or cure esp if inexpensive).

6 Remember (KEY POINT) overdiagnosis is any diagnosis that does not bring benefit (without of course reading anything on new Lyme abx protociols)
Having asserted that a chronic Lyme diagnosis does not n bring benefit, the diagnosis can be regarded as overdiagnosis and thus the condition is rendered clinically null and void. Whether it really exists is a moot point. Key point but don't be too explicit about it.

7) One thing, do not mention that alternative diagnoses and non medicalising assessments are often useless and therefore by this wisdom overdiagnosis or akin

8) Show a reasonable disposition "We can still learn from this phenomenon and must listen more" but don't say what the outcome of listening will be. But you will seem nice and humble. Always a good look.

Nuspeak unmedicine basically.

Now let's discuss how beneficial BPS assessments/diagnoses are to those with genuine chronic Lyme, which seems to persist despite being denied the oxygen of publicity. BPS for my palsy in 2014 , pounding heart, pains in leg that I had not had for years? Could have been sarcoid of course or Lyme reinfection or sth else but not on the basis that it was not chronic Lyme because the diagnosis is by nuspeak logic illegitimate per se.

Plenty on board here who are sceptical of many diagnoses of chronic Lyme but "it does not exist or diagnosis always and per se illegitimate " I hope is a minority opinion.

Perhaps one day she will clarify what her painting means in answer to precise questions.

 

I think there is something to your point here, because the studies I have read wrt phantom limb pain specifically show a “repurposing” of neurons that were previously dedicated to receiving pain input from localized sensors in that limb.

Once there’s a prolonged period of no input whatsoever, those same neural circuits start being triggered by other input networks, indicating that they’re effectively being repurposed (though this might be an over-reaching interpretation of the data).

But those same neural circuits are still connected to other circuits that “believe” the first circuit’s output to be related to pain from the limb. So something like touch stimulation on another part of the body might end up rerouting through circuits that other circuits “expect” to be activated only by pain input from the limb, leading to incorrect attribution of the source of that stimulus.

It’s not really understood how mirror therapy works, but it’s assumed that it has something to do with some kind of correction happening at this step.

So it shows that there is the potential for “signal crossing” that results in incorrect attribution of the source of a stimulus, but crucially, it’s triggered by quite a large-scale restructuring process after a profound change in input. There’s no evidence that anything similar is happening in ME/CFS (or other illness, for that matter).

At most, you can point to phantom limb pain to say it’s “possible” for the brain to do something like hallucinate pain, but as others have already noted, that’s an empty statement unless you can show the same mechanism in a different circumstance like ME/CFS.

 

That’s a good point that I had not even considered. Even if you repurpose nerves locally, there are probably no biological mechanisms for updating ever other related circuit.

It reminds me of how IT infrastructure becomes a patchwork of different programs, and the other programs will not automatically adapt to changes made in one.

And we think of nerves as wired networks that feed into another much more complex wired network (the brain), I don’t think we can take it for granted that the brain is able to differentiate between the origins of the signal, i.e. that it carries as sender’s address. It would be more like ‘the car that came down that road comes from Manchester’, but it might actually have started in Liverpool.

 

The first line in fluent Mancunian would be "Wha' i' is , is , is" - just for clarity

 

This surprises me as a way of describing things but I am not familiar with recent data. My understanding was that pain fibres from the left leg, when the left leg has gone, go on providing signals interpreted as pain in the left leg. I had thought that afferent signals to the cell bodies arose in dysfunctional stump tissue but maybe there is retrograde degeneration of the dendrite to nearer the dorsal root ganglion?

I had heard of mirror therapy and wonder if there is good evidence for it working.

 

Looking up mirror therapy it looks like a fairly plausible way of changing contextual input. There are more familiar examples, like putting ice on a toe you have just inadvertly hit with a fourteen pound hammer. The pain vanishes in less than a second, just by stimulating another spinothalamic pathway. Not sure one needs to postulate repurposing in any of this.

It is much less effective telling the pain in your toe to STOP or persuading yourself that the pain really isn't that painful. As you point out in another thread @jnmaciuch, there is a big jump from using any of this to validating a theory of retraining in ME/CFS.

 

Just to clarify, the “repurposing” I mention is specifically to explain why the aberrant pain perception arises in the first place. Iirc it was shown by activation of the same neuronal cluster formerly activated only by pain in the limb, which after limb loss gets activated by different stimuli but is still perceived as limb pain (It’s been a while so I’d need to go back to the literature to confirm I’m remembering correctly).

It wouldn’t be an explanation for how the mirror therapy works. I agree with you that other pain processing explanations would suffice to explain the specific phenomenon in mirror therapy, which would function on the contextual level

And there’s no evidence of any “repurposing” which would imply that other types of chronic pain are arising from the same mechanism as in phantom limb. Added: so appeals to phantom limb to explain other chronic pain are a moot point

[Added:] the study I was thinking of was from Ramachandran showing cortical reorganization was associated with touch stimulation on the face being perceived as limb sensations. I’m having trouble linking a paper for some reason (a 1998 review that discusses it and some additional validating evidence).

I believe that you’re also right about the stump tissue neurons and there still doesn’t seem to be a consensus about one over the other, so perhaps it’s a bit of both.

 

So, the dark side of neuroplasticity? Which makes sense. If it can do good things, it can definitely do bad things like that.

 

Reply: Muscle abnormalities in Long COVID | Nature Communications

Apologies if already posted. Response to "it's all deconditioning" theorists. May even represent a correct use of the term "refute". FAO Dr O'Sullivan.