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Understanding functional neurological disorder in the context of personal injury litigation

What is FND?

Functional neurological disorder (FND) is a medical condition in which there is a problem with the functioning of the nervous system and how the brain and body sends and/or receives signals, rather than a structural disease process such as multiple sclerosis or stroke.

The symptoms of FND can include:

  • Functional limb weakness – weakness of an arm or leg
  • Functional (dissociative) seizures – episodes that look and feel like epileptic seizures or faints
  • Functional sensory symptoms – reduced sensation in a body part
  • Functional movement disorders – involuntary movements such as tremor, jerks, spasms or difficulty walking
  • Functional tremor – uncontrollable shaking of the arm, leg, body or neck
  • Functional cognitive symptoms – problems with thinking, memory or concentration
  • Functional gait disorder – problems walking
  • Functional tics – repetitive complex movements or vocalisations

Common associated symptoms can include feeling spaced out, fatigue, chronic pain, sleep problems, headaches, anxiety and low mood. Many individuals with FND experience a combination of several of the above symptoms. 

Despite the potential severity of the condition, it is poorly understood and resourced in terms of diagnostic and treatment services.

What causes FND?

Whilst the causes of FND are not fully understood, it is thought to be related to a problem in the function of the nervous system and the way in which the brain sends messages to, or receives messages from, the body.

It is generally accepted that there are various factors which may make someone more vulnerable to going on to develop FND, including the presence of other functional disorders, neurological conditions, mental health issues and a stressful life history or events. It is thought that there may then need to be some sort of 'triggering factor' or event which leads to FND. This could include, for example, some sort of illness or physical injury.

It is thought that these predisposing factors, such as a stressful life history or events, may make people more vulnerable to developing FND on the basis that their 'fight or flight' response is sensitised so that it 'alarms' more easily in later life, or they have a tendency to 'dissociate' as a response to threatening or painful experiences. 

How is FND diagnosed?

FND is listed as a rare disease and, indeed, the causes of the condition and its diagnosis remain relatively poorly understood. As FND is essentially a problem with the 'software' in the brain as opposed to the 'hardware', scans are usually normal.

In a study by Vuilleumier P et al. (Brain 2001; 124: 1077–1090) four people with FND experiencing numbness and weakness down one side of their body underwent scans using a SPECT machine, which measures blood flow in the brain. The study concluded that the scans indicated that when the individuals were experiencing symptoms there was a part of the brain called the thalamus – which is often described as the 'relay station' of the brain - that was not functioning properly. When their symptoms improved, their scans improved too.

At present, there is no opportunity to diagnose FND through any sort of functional neurological imaging or blood test and therefore it is impossible to prove FND in that sense. Instead, diagnosis is approached by way of a thorough assessment of the patient’s history and symptomology by a neurologist familiar with the features of FND and other possible neurological diagnoses that should be considered in that patient’s circumstances. Many patients will receive a range of other diagnoses and may be treated accordingly before they receive one for FND.

How should FND be addressed in the context of a personal injury claim?

An FND diagnosis in the context of a personal injury claim can give rise to unique issues, not least because the physical, sensory and/or cognitive symptoms are essentially incapable of being explained by traditional scans or testing and it can, therefore, be viewed with scepticism or a lack of understanding of the interplay between the neurological and psychiatric components of the disorder. 

With that being said, the symptoms can be severe and thus have a debilitating impact on the life of the individual. FND can have a significant impact on that person’s ability to work, their accommodation needs and therapeutic needs, which may include physiotherapy, occupational therapy, psychological therapy and speech and language therapy. Indeed, evidence suggests that people with severe symptoms can improve with intensive inpatient rehabilitation which often combines input from specialist physiotherapists, occupational therapists and cognitive behavioural therapy.

A key issue in supporting a claimant who suffers from FND is, of course, proper understanding of and empathy to their condition. This is particularly the case if that claimant has been met with doubt or misunderstanding previously; it is essential that they feel supported by a legal team that understands the true nature of the condition and its credibility. 

Equally, a claimant must be given proper advice with regards to the potential challenges that may be raised by an opponent and experts instructed on their behalf, including unhelpful and outdated misunderstandings such as it is 'all in the head' and labelling the condition as a fictitious or a purely psychiatric condition. A claimant should be supported in understanding how arguments such as those may be addressed in the claimant’s own evidence, including within the medical evidence and lay witness evidence.

Psychological and psychiatric factors are undoubtedly important in the context of FND and most experts consider that the condition occupies a grey area between neurology and psychiatry. The importance of instructing appropriate experts in neurology and psychiatry with particular expertise in and experience of FND must not be underestimated. Likewise, any experts must understand the importance of engaging with their expert colleagues instructed in the matter, particularly in light of the unique interplay between neurology and psychiatry.

With that being said, there are unfortunately cases, as in every area of personal injury litigation, in which claimants are found to have been fundamentally dishonest in the reporting of symptoms of FND. The difficulty of course comes from that fact that, on examination, both genuine claimants and dishonest claimants can report very similar symptoms and challenges. As in any personal injury claim, careful attention must be given to ensuring that a claimant is able to produce consistent evidence, that is corroborated by their medical records and supported by the medical evidence and those who support and care for them. The very unfortunate truth is that due to the nature of FND and the difficulties surrounding its diagnosis, it can mean that it is seen as an easy target for those disingenuous claimants attempting to take advantage of the process. This runs the risk of making genuine sufferers feel that their condition is not taken seriously or believed or that they are malingering.

Understanding what the prognosis looks like in cases of FND is also critical in terms of ensuring that it is dealt with appropriately in a personal injury claim. In people attending general neurology clinics in the UK who receive a diagnosis of FND, about 40 per cent of people say they have got better within a year. 

What does this mean for a claimant? 

Firstly, claimants must be supported with early interim funds to secure targeted and focused rehabilitation to ensure that they achieve their maximum recovery. This is of course the case whether or not liability is admitted, by seeking to engage the insurer under the terms of the Rehabilitation Code of Best Practice. 

Secondly, careful consideration must be given to the quantification of, in particular, a claimant’s future losses based on their individual prognosis, as guided by the medical evidence. If, on the balance of probabilities, the expert evidence suggests that their prognosis is positive, then that will have an obvious resulting impact on the quantification of any future losses, including future loss of earnings, future therapy, future aids and equipment and accommodation. 

Thirdly, detailed witness statements from those who see and experience the impact of the condition are essential, particularly in light of the issues with diagnosis that have already been considered.

Living with a neurological condition such as FND can cause a whole range of challenges for those effected. Claimants with FND must be supported with understanding and empathy. 

If a claimant suffers particularly with fatigue or struggles with concentration, then could long conferences and complex advice be delivered in a way that facilitates their engagement and participation more effectively? 

Those representing should consider the time of meetings, the need for breaks and whether it is in the claimant’s best interests for them to hear the experts discussions or not. If they suffer with limb weakness or movement disorder, would they prefer for meetings in person or expert assessments to be held in their home, or another place in which they feel most comfortable? As with any seriously injured claimant, exceptional client care is a paramount consideration with advising those with FND. 

Claimants must feel supported by legal experts with compassion and understanding of their individual needs.

Find out more about how Irwin Mitchell is supporting those affected by FND at our website