Presented at the British Neuropsychiatry Association [BNA] annual conference, Thursday 26th May 2022.
Bio, as shared by BNA:
Alan Carson is a Consultant Neuropsychiatrist to Rehabilitation Medicine at the Astley Ainslie Hospital and to the Department of Clinical Neurosciences at the Western General Hospital.
Functional neurologic disorder often occurs in association with physical trauma or psychologically stressful events. This means they are commonly a complication of accidents and as recognition improves they are more commonly encountered in the setting of personal injury. It is important to recognise that there is nothing new here, similar patients and presentations have been recognised in the Court over the past century. In this talk I will describe my approach to assessment of such cases and how one might attempt to integrate current scientific understanding in a way that helps the Court decide what has happened and who was to blame. We will cover diagnosis, exaggeration, onset, risk and triggers and treatment.
Professor Alan Carson:
Thank you. It’s a real pleasure to be here. It’s lovely to see everyone in the flesh, as everyone’s commented. I must confess I’ve got a bit of performance anxiety about this. I haven’t given a lecture in front of people. Suddenly I decided Zoom’s quite calming as you face a faceless ether. So, yeah, apologies if you hear tremulousness.
So, I do medical legal assessments across a range of conditions, but FND in particular. And it’s quite an interesting process because it does actually force you to think about some of the things that you can glibly say, particularly about aetiology in a clinic letter without getting questioned too much. And it kind of just makes you think a little bit about is that true, if you see what I mean? I quite enjoy it from that point of view. There are other aspects of it I completely hate, I have to confess, but some of it is quite interesting. This is going to be a very practical guide through. There’s no evidence base behind it. It’s what one of my neurosurgical colleagues calls EBM, which for neurosurgeons is ego-based medicine. So, yeah, these are just my thoughts, and you’re very welcome to disagree with them.
So, the first question is, are we sure what’s actually wrong? Do we know what it is?
And I think most people are quite familiar with the basic tenet of a functional disorder, that we’re looking at symptoms and signs that have internal inconsistency and incongruity with the mechanisms of pathophysiological disease. And I always think that’s most clearly indicated in this sort of drawing of a tubular visual field, one of the more common functional visual symptoms [see slide as shared in the presentation].
There is never going to be an antibody in a classic sense or a brain lesion that will explain this because it defies the laws of optics, not just of pathophysiology. And that’s what we’re kind of looking at as the basic tenet of diagnosis.
And we know that if we apply this approach, diagnosis is pretty accurate. It’s certainly on a comparator with anything else in the clinical neurosciences and either psychiatry or neurology, absent a full-scale sort of diagnostic test.
And of interest, as has been pointed out in numerous previous lectures, this sort of curve was flat long before the sort of dates of fMRI imaging, which is probably the one big game-changing imaging modality of significance [see slide as shared in the presentation].
But is it really that easy? I just want to comment on a couple of areas because quite a lot of the patients I get asked to see get their diagnosis of a functional disorder from me for the first time in the context of a medical legal assessment when they’ve been sent with something else neuropsychiatric to examine.
This is a review John [Stone] and I wrote, which I rather like actually [see slide as shared in the presentation].It’s from Practical Neurology, which is a sort of quiet little journal, but almost all the papers in it are absolute sort of gold mine of clinical knowledge. It’s a really good journal to follow if you’re from the psychiatry side of neuropsychiatry, because there’s a lot of really helpful, this is basic mainstream view and where to get it. And we can think of neurological conditions, which may be mistaken. for functional disorders. And we can think of the chameleons, functional disorders, which might be mistaken for neurological conditions. If we’re thinking of the mimics, a few of the sort of clues I find helpful over the years, because just occasionally things get sent as functional and you’re saying, no, actually, I don’t think it is.
Sudden onset functional disorders are incredibly rare and by sudden onset I mean that speed of onset. They evolve so the stroke-like functional presentations actually tend to evolve over 10 to 15 minutes. It’s not quite that instantaneousness that you get in other areas and there is usually some form of other trigger which might include panic attack.
Be very cautious about any case where there is a lack of altered sensation or pain. If people report no sensory symptomatology at all, I would be very cautious. Where there’s no sense of depersonalisation involved, I’d be a bit cautious, not quite as much as the lack of sensation.
What I look for as a key finding is hypervigilance to the affected area. I think that altered and dysregulated attention is fundamental to the mechanism of functional disorders and I tend to be very cautious where people aren’t showing some signs of altered or deviated attention and with that comes hypervigilance particularly to touch. I know a lot of psychiatrists don’t examine people physically, but I really would recommend it. You do just learn so much about the condition from laying hands on people and absent hypervigilance, be cautious. Similarly, patients will always complain of some form of subjective memory impairment. It’s not true memory disorder, but some sense that the brain thinking is fogging. Be very cautious in the areas of muscle wasting. And be cautious where there’s consistency across modalities of investigation. So for instance, somebody might hobble to the couch and then have zero out of five power on the couch, which is inconsistent, if you see what I mean. And lastly, I think functional disorders are busy conditions. There’s just a lot going on. Where you get a single discreet complaint, you’ve done the full assessment in 10 minutes, just be careful.
And I think just with view of Chris’s talk, which I enjoyed very much, I do think hypervigilance or lack of hypervigilance in something that does look functional is a real red flag for potential falsification. This is the thing we worry about. And people sort of talk about, well, I want to err on the side of caution. But what I really want to try and convince you is chameleons are actually much more important.
So that’s been having quite a few of these cases. I started doing a memory disorders clinic in the last few years, and this is standard fare of me. A 46 year old woman had a recent diagnosis of Alzheimer’s disease based on poor performance and psychometric tests. And please note she passed performance validity testing. Performance validity testings, I think, have big accuracy problems. And I really commend to you Laura McWhirter’s excellent review of them. Had been advised on end-of-life planning, power of attorney. This is a 40-something woman with a young family. No attention paid to the fact there was normal imaging. Main symptoms, blank spells during the day, loss of over-learned material, very anxious. Retained ability with praxis, which I think is quite a useful sign in people with supposed Alzheimer’s who don’t.
And it was a clear-cut functional disorder. And this woman’s life had been devastated for the four years prior to me seeing them. There is an increasing trail of negligence cases. I think perhaps helpfully so, in a corrective balance of people just not being cautious enough or thinking enough about functional disorders when coming to diagnosis. So I just want to suggest that while we all worry about mimics, because that’s the way we’ve been medically trained, we should worry much more about the chameleons.
And the kind of things that I think encourage that are just thinking the patient’s a bit nice, a bit stoical. Actually, what we really mean is a bit like me, and I wouldn’t get a psychiatric disorder. So there’s a huge sort of stigma issue to it. They do have to happen for the first time at some point. The lack of stress. You know, coming on after injury or minor pathological disease is one of the main triggers. The patient seems happy about psychological causation. Actually, if you systematically study patients with functional disorders, the majority have quite mixed, nuanced, non-dualistic view that both stress and physical factors are relevant. It’s doctors who like to extreme ends of those spectrums.
An established diagnosis of known epilepsy, known MS, particularly one where you’re never quite sure where it came from, but it’s been in every clinic letter over the last decade. Just always try to find out. And old people do get functional disorders and incidental abnormalities occur.
A few areas that I think have come up in medical legal cases quite frequently [see slide as shared in the presentation]. Facial symptoms. Facial symptoms are quite common in functional disorders. They look like weakness, but they’re really a sort of dragging dystonia of the muscles, particularly in platysma. Convergence spasm and just occasionally functional… What’s the word? Opsoclonus of the eyes, common. Variable ankle clonus, if you’re just very tense and got hypervigilance, you can become hyper-reflexic and you can get a pseudo-clonus around the ankles. Asymmetric reflexes, if you’re dealing with big guys and particularly big guys on opiates, having just no reflexes is quite uncommon. And a degree of hypervigilance will just slightly distort the symmetry of reflexes.
Urinary retention is a big one. Functional urinary retention can cause you to damage your bladder. And it’s one of these sort of slightly challenging things the way we speak, but we see people whose bladders are absolutely knackered after an initial presentation with function cauda-equina. They go into retention, they get left and they get this standard thing and axial or proprio spinal myoclonus. So these are just little areas to be aware of in some cases, particularly in the context of sort of odd brain injuries. They tend to crop up or supposed encephalitis.
But then somebody says, “We found something on the scan.” Just to remind ourselves of the odds [see slide as shared in the presentation]. My basic rule of life in all things medical is the more complicated the imaging modality, the more chance there are of false positives. And I found that stood me quite time.
Once you’ve seen it and you’ve decided it’s functional, by definition, you’re talking about something that’s inconsistent internally and incongruent. So the alternate diagnosis is always going to be some form of exaggeration. And Chris has gone through it in some detail [see slide as shared in the presentation].
I think the way I would tend to think about it is on the spectrum. You’ve got the spectrum of the level of intentional symptom production, and you’ve got the degree of motivation and awareness. And I highlight that because that’s kind of how I would tend to assess things in clinic.
So I think what we’re really talking about is knowingly falsifying intentional activity [see slide as shared in the presentation]. I don’t really get worried about the motives and whether it’s to convince or to deceive or where it’s coming from. Essentially, in medical legal settings, quantum is based on the level of disability displayed. That’s how you’re assessing it. And what we want to know is, is that disability accurate?
So we need to say, first of all, what is the person actually claiming works or doesn’t work? When they say my arm is weak, do they mean it hangs completely lifelessly and never moves? Or do they mean it’s just got reduced power? So we need to know what the impairment is and then what they can do with it. So if you have somebody who’s wheelchair bound who says, I never walk, that’s slightly different from somebody who says, I tire after three miles and I need to slow down. So we get that.
And then we look for all evidence of objective function. And we try to say, is there incompatibility between claimed function and actual intentional function? The reason I say intentional function is: getting at things which you must have awareness of. So you see somebody with a functional disorder in a wheelchair transferring into a car, you will see use of muscles paradox at the time of movement, but they’re distracted because they’re doing a busy movement trying to get into a car. And I don’t think that means anything. But if somebody who’s in a wheelchair and apparently can’t walk gets out of their wheelchair to go and switch over the telly: well, you can’t be unaware of that. No one I ever see with spinal injury has a wee walk and doesn’t think that’s unusual. You know, this is clear cut. So I would look for the intentionality of the action and therefore intuit from that how much awareness there must be that that was done and see how compatible that was from the claim. And I just don’t get involved in commenting on motive because that’s really just giving rise to your entire areas of prejudice. We haven’t a clue whether somebody is trying to convince us or deceive us, etc. What we can talk about with medical expertise is the degree of incompatibility and whether that’s plausible within what is known about that disorder.
Okay, so we’ve decided what it is and we’ve decided it’s genuine. The next question is, well, was it caused by the accident? And we might think of this in terms of how, what is the mechanism of symptom production? And I’m not sure anyone’s ever said it better than Paget. It’s an old chestnut now. ‘She says . . . ‘I cannot’. It looks like ‘I will not’; but it is ‘I cannot will [see slide as shared in the presentation]. And I think there is increasing empirical evidence to support the notion that that is at least in part what underlies functional disorders. I’m feeling a bit embarrassed because I chose this lovely slide by Patrik Vuilleumier’s group, but two of the best contributions, on the card, come from Tony and Val who are sitting in front of us. So consider yourself cited in absentia.
But I think really in medical legal setting, we’re interested more in the why. Why did it happen to this person and not to someone else?
And I think as far as evidence base of risk goes, the strongest evidence still lies behind stressful life events and maltreatment previous aversive experiences [see slide as shared in the presentation].
Now, I spent a long time saying this isn’t the whole story, and I do stand by the fact this isn’t the whole story, but it is a story and it does increase the odds of having a functional disorder [see slide as shared in the presentation]. But a significant proportion, and we don’t know how many, we might guess a third, it’s very hard to do research, maybe don’t have such an experience, doesn’t really explain why one patient gets a seizure and another paralysis, or indeed some patients just get depressive illness and no functional symptoms at all. And it certainly doesn’t explain why it starts on a particular date. So these are things we’ve got to think of.
So if we’ve got somebody presenting today, why the 26th of May? Well, this is where the medical legal overlap comes [see slide as shared in the presentation]. The single commonest trigger towards a functional disorder is some form of modest or often modest physical injury, probably in about 38%. And that’s been replicated in a couple of prospective studies since we suggested this a few years ago. It is important to remember, however, that does mean that more people don’t have their condition triggered by a physical injury. So there are multiple reasons. And just because somebody happened to have physical trauma around the time of onset doesn’t mean that was the cause.
And I think we’ve got to just be aware that things are happening in the brain too. I don’t want to linger over this. This is a sort of different talk for a different day, but we tend to be very dualistic. As soon as somebody sees any sort of shift of an antibody or an inflammatory marker, they kind of think they’re dealing with something else [see slide as shared in the presentation]. But these are often just different settings for looking at the microscope in a different way. There must be fundamental underlying physiological mechanisms for the expression of a genuine symptom. And just sort of being aware of these things can run concurrently, I think is helpful conceptually as you try to navigate your way through this.
So the fundamental question I’m asking is, was this person at such high risk that symptoms were inevitable?
And I think I’ve stolen this actually from a paper that Chris wrote [see slide as shared in the presentation]. So my ‘tactometer’ has not been too far out in citing other speakers. But this is the typical sort of thing you’re faced with, a set of case records in somebody. And you’re kind of going through and trying to get a timeline of what have their symptoms been like over the lifespan. Now, sometimes there is just absolutely nothing. There is major trauma and there’s functional overlay in the aftermath. And that’s very straightforward.
But more commonly, you’ve got this sort of thing going on [see slide as shared in the presentation]. And there’s a few different things. There’s a viral illness with fatigue. There’s then a car accident. They’re off work. The marital problems start and make it a bit worse. But the marital problems appear to have come out of the pain complaints. But you’re just wanting to make sure there wasn’t an affair back in 2002. And really, it’s an extension of that. So you’re trying to unpick and really put your money where your mouth is and say, is there more than 50% chance that that car accident triggered off the chain of events?
And I guess how I try to approach that in a sort of fair way, and what I try to do is to lay out a structure, because the one thing you can absolutely bet on is if something goes to a proof, that other stuff you were unaware of will come out the woodwork [see slide as shared in the presentation]. So I think it is helpful to give a structure of how your thoughts go so that a judge can see how this other information fits in.
I was interested in Chris’s comments on witness statements. I found witness statements to be singularly useless in the last 20 years. I’ve never had a statement from anyone who wasn’t a really cheerful, active, happy go lucky person. I live in Scotland. There are no happy go lucky people apart from those who are suing others in personal injury context. So, you know, I think it’s a psychopath test. You have to be a complete psychopath to say, ‘oh yeah, they’re just a waster’. It just doesn’t happen.
So what I’m trying to think of is how out of the ordinary was the precipitating event? So going away from functional disorders and just thinking of back pain, there’s almost always a triggering event to an episode of acute back pain. And sometimes that can be quite major, but sometimes it’s simply bending to pick a sheet of paper off the floor. What I’m kind of thinking in that model is if it was because you just picked a sheet of paper off the floor, that was going to happen anyway. And I kind of in my mind have a similar test. I’m thinking how marked was the physical injury? How marked was the associated psychological distress? So you do get events that are really quite horrific. Seeing somebody last week’s car was knocked off the road at 80 miles per hour, spun around about 15 times and came to a rest on a grass verge. Actually, the transfer of energy is relatively modest in such an event. There was no sudden halt. But I think most of us could accept that it’s a pretty horrific thing to go through. And, you know, the next brain that you might inevitably get is going to be occurring in a context of real fear. But I think also there’s a question of did it change the behaviour of others? And did other people view you differently? The person who has a mild head injury one day comes into casualty the next day after a faint, in my experience, has far greater chance of being diagnosed with having had a seizure than they would have ordinarily.
And I’m basically trying to look at this severity of the trigger versus the extent of prior risk and seeing how far down that line we can take the case [see slide as shared in the presentation].
I look for perpetuating factors and just trying to see how the person responded. Can we contextualize this for the development of a functional disorder in the normal time? [See slide as shared in the presentation].
And then one is asked, what is the prognosis?
Jeannette Gelauff, one of our researchers, did this very helpful prognosis of functional motor symptoms review, which is totally legally unhelpful because it’s exactly 50/50 and you’re always asked to swing on balance of probability one way or the other [see slide as shared in the presentation]. I think we’ve got to be cautious. When we try to get the best models, we can really only explain at most about a third of the variance. So there’s a lot about who does well and who doesn’t that we don’t know. I think the only real predictor is early improvement.
This is the constant claim: ‘Don’t worry, it’ll all go away when the claim settles’. Systematic reviews of this reveal no support for this notion at all. There are problems with the research. They also reveal the fact that the research is appalling [see slide as shared in the presentation].
I think the best study comes from, I don’t know if it’s Saskatchewan or Saskatchewan, or maybe it’s another pronunciation, but essentially they changed their litigation system and they showed that whiplash is about 15% worse in an adversarial versus no fault compensation. It’s not actually a big change [see slide as shared in the presentation]. So I think, yes, there is something, litigation is a horrible experience, but it’s not as bad as we think.
Can we do anything to treat?
Yes, we can. I’m not going to dwell on that. You can read this paper [See slide as shared in the presentation].
What I just want to highlight is from our SNSS [Scottish Neurological Symptoms Study], only about 5% of patients in routine practice are actually getting treatment [see slide as shared in the presentation]. So the dilemma in a medical legal setting is for many patients, I might be the only doctor they see who knows something about functional symptoms. And if I’m instructed by the defenders, although I do try to be strictly neutral, why should the claimant trust me? And other clinicians having me overturn their diagnosis of encephalitis or diffuse axonal brain injury and say, this is functional, may not like that. And I have to go back and say, oh, I’d like you to change direction. It’s not straightforward.
And I think it raises the question of who carries risk for treatment [see slide as shared in the presentation]. It’s counterintuitive because it probably depends on desire willingness to get better which is an unknown despite protestations to the contrary if you treat pre-settlement it’s actually a defender carries the risk because if treatment fails you’re going to settle on the basis they’ll never get better whereas if it’s treatment after settlement the claimant carries the risk because it will generally be changed on the fact that some form of treatment will improve things
Just in the last couple of comments often asked do they need any care or adaptations? Very helpful paper, an occupational therapy consensus paper published in GNMP, Claire Nicholson from UCL led and I’d recommend. I think in general the answer is not by and large it’s unhelpful for functional disorders, but I think you’ve got to consider how they manage maybe help for heavier jobs like heavy gardening, etc., where they are in the litigation and treatment process. I don’t think it’s an absolute no. It’s a kind of, well, I’d rather not and individualized.. This is the paper. And yeah, it’s tricky [se slide as shared in the presentation].
Other experts. I think for the lawyers, it’s a case of how many people have they actually seen? I find pain specialists tricky because they all tell people you’ve got chronic pain. We don’t know why it is when we do and you’ll never get better, but you learn to live with it. And I kind of have an opposite view. And there’s the issue of dealing with rogues. Tony generally called them mavericks. I’m going to be less polite and call them rogues. And there are two or three very active in the British medical legal scene. Everyone knows who they are. And I think lawyers need to take a long, hard look at themselves if they instruct them.
So I think it’s a complex area.
I think ultimately it’s just about having medical expertise. Try not to be a lawyer. Try not to get sucked into the litigation bit and just try to do your job as a doctor because that’s the thing you do. You’re not a lawyer. Don’t start becoming an advocate or a barrister. That’s the route to downfall. I’ll stop there. Thanks.