Brain Injury classification podcast

Emma Eccles: Hello and welcome to this Weightmans podcast brought to you by the Weightmans Brain Injury Technical Unit. My name is Emma Eccles and I’m a Partner in the Weightmans Large Loss team based in Manchester, and Co-Chair of the Brain Injury Technical Unit. Today I’m delighted to be joined by Jamie Hill, Barrister at Nine Chambers. Jamie’s caseload is a mixed bag of large loss and serious injury cases up to £1 million. Jamie was called to the Bar in 2016, predominantly acts for defendants, and is ranked in both The Legal 500 and Chambers and Partners. Today we’re going to be doing some horizon scanning. Our intention is to explore the current brain injury classification system and look at the new system currently being trialled in the United States. Firstly, thank you, Jamie, for joining me today. Jamie Hill: Emma, thank you very much for inviting me onto your excellent podcast. ⸻ Emma Eccles: Jamie, could we start by talking through the current classification system? Jamie Hill: Of course. The current classification most commonly used is the Mayo Head Injury Classification, which has been in use since around 2007. It looks at positive evidence contained within the medical records and categorises injuries into three distinct groups: Category A – Moderate to severe traumatic brain injury (TBI) Category B – Mild or probable TBI Category C – Symptomatic or possible TBI To determine which category a head injury falls into, clinicians consider four clinical markers: Glasgow Coma Scale (GCS) Duration of loss of consciousness Duration of post-traumatic amnesia Neuroimaging findings For example, a loss of consciousness lasting more than 30 minutes would fall into the moderate to severe TBI category. A mild or probable TBI might involve post-traumatic amnesia lasting anywhere from a few moments up to 24 hours. A symptomatic or possible TBI would typically involve a history of head trauma together with symptoms such as headache, dizziness or nausea. That’s a broad overview of the current classification, but I suspect most of our listeners will already be familiar with the Mayo Classification. Emma Eccles: Thanks, Jamie. The Mayo Classification is certainly the one our medico-legal experts most commonly use, although it’s worth pointing out that there are other classification systems and there isn’t one definitive guide. I’d also like to emphasise the importance of obtaining early records when assessing a brain injury using the Mayo Classification. Access to 999 records, ambulance records and A&E records can be invaluable. These often contain important information about whether the claimant lost consciousness and their recorded GCS score. Early witness statements can also be extremely helpful. Sometimes they’re overlooked where liability isn’t in dispute, but they can play a significant role in quantum by helping assess the severity of the brain injury. It’s definitely worth obtaining those witness statements at an early stage. Could you explain some of the shortcomings of the current Mayo Classification and the issues we commonly encounter as defendant insurers? Jamie Hill: Of course. One of the principal difficulties is that categorisation is determined solely by the patient’s acute presentation and isn’t particularly sensitive to how that patient recovers afterwards. Another issue is that the classification doesn’t distinguish between moderate and severe injuries—they’re grouped together into a single category. When you look at what’s included within “moderate to severe”, it ranges from fatal traumatic brain injuries through to someone who loses consciousness for 30 minutes but then makes an excellent recovery. Treating those patients within the same category cannot really be right. It’s also potentially unhelpful to tell someone they’ve suffered a moderate or severe brain injury when their prognosis is actually very good and they’re likely to recover well. Another surprising aspect of the Mayo Classification is that it’s possible to be diagnosed with a moderate to severe brain injury without any detectable brain damage on imaging. The classification also relies heavily on the accuracy of the acute clinical records—particularly GCS, loss of consciousness and post-traumatic amnesia—with relatively little reliance on objective investigations. GCS itself can be subjective. Following a traumatic accident, distinguishing between someone who is orientated and someone who is confused can be difficult, and that distinction changes the score. We often see GCS scores fluctuate within the records. That may reflect genuine clinical change, but I suspect it’s often because different clinicians interpret the assessment slightly differently. Furthermore, GCS can be affected by factors entirely unrelated to brain injury, including intoxication, sedation or medication. Those patients may present with a reduced GCS and post-traumatic amnesia without actually having sustained a brain injury. Whilst the Mayo Classification allows GCS to be discounted where there are alternative explanations, GCS remains central to the classification, which doesn’t leave experts with much else to rely upon. Finally, following a traumatic event, claimants frequently report a brief loss of consciousness. That isn’t necessarily because they’re being dishonest. Someone who is dazed and confused may genuinely believe they lost consciousness, but being dazed isn’t the same as being unconscious. As defendant lawyers and insurers, those reports can be difficult to challenge, particularly where there are no independent witnesses and we’re reliant solely on the claimant’s recollection. Emma Eccles: Thanks, Jamie. Those are all really helpful points. From a practical perspective, there are two particular issues I regularly encounter. Firstly, we’re often telling claimants very early on that they’ve sustained a moderate to severe brain injury. That inevitably affects both the claimant and their family—how they perceive themselves, how they approach rehabilitation and what they expect their future to look like. Secondly, there’s the impact on rehabilitation. Rehabilitation frequently begins before any medico-legal neurologist or neuropsychologist has had the opportunity to assess the claimant. Case managers understandably have to make decisions very quickly about the support that’s required. Without the benefit of expert opinion, claimants can sometimes be treated as though they’re more seriously injured than they actually are. Care and support may be introduced unnecessarily, creating dependence rather than encouraging independence, which ultimately isn’t in anybody’s best interests. That’s one of the practical difficulties created by this early classification of moderate to severe brain injury—it sets the tone for both the litigation and the rehabilitation pathway. Jamie, one of the reasons we’re recording this podcast is to horizon scan and look at the new classification system currently being trialled in the United States. Could you explain what this new framework involves and how it differs from the Mayo Classification? Jamie Hill: Yes, of course… The new classification system is being led by the US National Institutes of Health. It has been developed in collaboration with, I think, 94 experts from 14 different countries and is currently being rolled out on a trial basis in major trauma centres in the United States. The new classification system is called the CBIM framework, which stands for: C – Clinical B – Biomarkers I – Imaging M – Modifiers The intention appears to be to move away from rigid classifications such as Mayo, where an injury is categorised as mild or moderate to severe, and instead adopt a more individualised, multidimensional approach across those four pillars. Looking at what each of the four pillars entails, the first is clinical. This moves away from relying on a single GCS score. It requires clinicians to consider the individual subscores that make up the GCS, as well as pupillary reactivity, which is an important clinical indicator of brain injury. It also tracks symptoms during the acute phase and, as I understand it, into the longer term. It therefore considers more than simply the acute clinical presentation. The second pillar is biomarkers. This is a significant difference because it incorporates an objective, blood-based marker into the clinical diagnosis. There are certain proteins in the blood that spike following a brain injury where there has been damage to the brain tissue. If a blood test is undertaken within the first 24 hours or so, those proteins can be detected. This provides objective evidence of damage to the brain tissue, even where that damage is not visible on a scan. Speaking of scans, that brings me to imaging. Imaging is already used within the current system, but the new framework focuses in greater detail on microscopic or microvascular changes. The initial trauma CT scan is not always particularly detailed, and the findings may sometimes be reported using relatively vague or generic terms, such as “contusion”. The new framework requires greater specificity about the precise nature of the injury. It also places greater emphasis on obtaining higher-quality imaging at an early stage, rather than waiting months or years to undertake, for example, an MRI scan. At present, an MRI scan is often only undertaken where the patient continues to experience persistent symptoms. Finally, the fourth pillar is modifiers. This formally introduces the biopsychosocial model, with which many of our listeners will be familiar and which is already used in a medico-legal context. It requires clinicians to obtain, document and take into account pre-existing factors. For example, does the claimant or patient have an underlying psychiatric condition? Have they previously sustained a brain injury or concussion? Are there social factors that could influence their recovery or prognosis, or explain their current presentation? It is therefore about incorporating what would effectively be causation arguments at an early stage and considering the circumstances in the round and on an individualised basis. Emma Eccles: That’s really helpful, Jamie. Thank you. As you say, it involves looking at a wider range of factors in the round and making a more informed assessment. What changes do you think we could see in our own cases if this new classification system were introduced over here? Jamie Hill: I think it would result in changes. There would probably be much greater objectivity within the system, which should increase its reliability. Overall, that would probably be a good thing. I’ve thought of three examples that may help illustrate the differences between the two systems. For the first example, imagine a 25-year-old who is involved in a minor road traffic accident. Several years after the accident, they complain of ongoing neck pain, headaches and confusion. There is also a suggestion that they may have lost consciousness for approximately one minute at the scene, which relates to the point I made earlier. Under the Mayo Classification, that injury would be treated as symptomatic or possible TBI. Under the new system, imagine that the patient is assessed by the ambulance service, taken to hospital and given a blood test in A&E. If the test is positive for the relevant proteins and the biomarkers are therefore positive, that would provide highly persuasive, or potentially conclusive, evidence that the patient had sustained a traumatic brain injury. It would consequently make it much more likely that their ongoing symptoms of headaches and confusion could be linked back to the accident. For the second example, imagine a 35-year-old who is assaulted at work. He is struck on the head and loses consciousness for approximately 20 minutes. When he regains consciousness, he is very agitated in the ambulance. Following the accident, a change in personality and memory difficulties are reported. Under the Mayo Classification, this would be categorised as a mild or probable brain injury. Under the new system, however, we would focus on the M for modifiers and how those factors would be incorporated into the clinical diagnosis. Imagine that the patient is an amateur boxer, has experienced five previously documented episodes of loss of consciousness, has sustained multiple head injuries and had already discussed memory difficulties with his GP before the accident. All of those factors would be considered clinically at the categorisation stage, rather than becoming the subject of legal argument several years later. It is likely that a patient within that cohort would be treated differently. Some of the difficulties identified from the outset may be attributed to the evidenced pre-existing conditions or alternative causes. For the third example, imagine a 45-year-old involved in a serious workplace accident who sustains a fracture. There is no evidence of brain damage on the imaging undertaken following the accident, and the blood test is clear. The patient is unconscious for three days, although they were sedated and intubated at the scene. They experience post-traumatic amnesia for one week and complain of ongoing but relatively modest cognitive impairment and headaches. Under the Mayo system, that would be categorised as a moderate to severe brain injury from the outset. Under the new system, however, the objective markers would indicate that there was no brain injury. There would be no evidence of injury on the imaging and no relevant biomarkers identified in the blood. I think this type of patient would be managed very differently under the new system. They would be unlikely to require significant neurorehabilitation and would be less likely to be told, managed and treated as someone with a severe brain injury, as may currently be the case. Emma Eccles: Thanks, Jamie. I think that final point about rehabilitation is particularly important and relates to something I touched upon earlier. From what you’ve described, the new system could help bridge the gap while case managers and therapists are waiting for a medico-legal opinion on the brain injury. It would provide a more thorough and nuanced assessment of the severity of the injury at an early stage, which would help inform both the case manager and the treating team. I also think the system could result in classifications becoming slightly more contentious and open to debate than they are now. That may be advantageous to defendants during litigation. I know that colleagues and experts will sometimes say that the precise classification is not necessarily the most important issue. They may say it is less relevant because the primary consideration is how somebody is functioning cognitively at a particular point in time. However, as I said earlier in the podcast, I do think classification is relevant. It affects how claimants and their families perceive the injury, how they envisage the future and the level of support they believe may be required. I also think it is a particularly important factor in early rehabilitation. Jamie, what sort of timescale do you think we could be looking at for implementation in the United Kingdom? Jamie Hill: Emma, you mentioned horizon scanning, and I think we are looking quite far out onto the horizon here. The framework has not yet been fully implemented in the United States. It may, of course, go no further and may not ultimately be adopted as a finalised clinical tool. I suspect it will be, although I may be wrong about that. Even if it is adopted in the United States, I have not seen any confirmation that it will be adopted in the United Kingdom, whether by the Department of Health, through NICE guidelines or by NHS trusts. Even if it is eventually adopted, we do not currently have an implementation date. With the best will in the world, I think it is likely to be years away. We also have to consider the practicalities. If NHS trusts adopt the framework, there will be a cost involved. Some trusts are still using antiquated technology, including fax machines. It can sometimes be difficult to bring the NHS up to modern technological standards, although that is not a criticism that can be made universally. Nevertheless, implementation will come at a cost. Imaging capabilities will have to be upgraded. Blood testing will also need to be available so that the relevant biomarkers can be checked, which will require investment in pathology services. Another important point is that the full framework cannot be applied retrospectively. If the blood is not taken and tested within the first 24 hours or so, that evidence is lost. It would therefore be difficult for an expert in a later legal case to apply the diagnostic criteria retrospectively if the relevant clinical tests were not undertaken during the patient’s acute presentation. Emma Eccles: I think that’s a really good point, Jamie. I have noticed in recent months and years that neurologists involved in our cases are beginning to discuss this new classification system, so they are clearly aware of it. They appear to be strongly in favour of it because, as we have discussed, it provides a more thorough investigation at an early stage and adopts a broader and more nuanced approach to brain injury classification. Another trend I have noticed, particularly in recent years, is experts being more willing to disagree with the Mayo Classification. They may say that, although the Mayo Classification indicates one result, they do not believe the claimant has sustained a brain injury or that the injury should be classified as moderate to severe. Experts appear increasingly willing to challenge the classification where they feel it does not accurately reflect the claimant’s injuries. Is that something you have also seen in your practice? If the US trial is not adopted over here, do you think our own medico-legal experts may nevertheless begin to adopt a broader approach to classification? Jamie Hill: Yes, I have seen that in my cases. I can think of several recent examples where a neurologist or neurosurgeon has said, “Although the Mayo Classification says X, I actually think Y.” In one case, the injury would have been classified as mild under Mayo, but the expert said, “I do not think this claimant is brain injured. I simply do not believe there is a brain injury here. I think the symptoms are better explained by other factors, and I am going to defer to psychiatry,” for example. I have therefore seen and recognise that trend. Ultimately, I think it is helpful for defendants. I also think that awareness of this new classification system will strengthen experts’ ability to take that approach. Even if they do not rigidly apply the new criteria or expressly say, “I am going to assess this case using the new CBIM framework,” they can recognise that alternatives to the Mayo Classification exist. They can say that other classification systems take account of factors such as pre-accident psychiatric conditions and that they are therefore going to consider those factors too. That gives them a proper and sound basis for expressing the opinion that the case should be approached differently from the way in which the strict Mayo criteria might otherwise dictate. Emma Eccles: Thanks, Jamie. Thank you again for joining me, Jamie Hill from Nine Chambers. This has been a really helpful review of the current Mayo Classification for brain injuries, as well as an opportunity to horizon scan by looking at developments in the United States and the changing approach being taken by neurologists over here. This has been a Weightmans podcast brought to you by the Weightmans Brain Injury Technical Unit. I’m Emma Eccles. Please do not hesitate to contact me or one of my colleagues if you have any questions arising from this podcast. Thank you very much for listening.