Navigating Functional Neurological Disorder Claims: Lessons from a Discontinued Case

Functional Neurological Disorder (FND) represents a significant and often challenging area within medico-legal practice, particularly in clinical negligence and personal injury claims. Unlike structural neurological conditions, FND involves disturbances in the functioning of the nervous system without evident structural damage. The recent discontinuation of a notable FND claim, as reported by Clyde & Co, underscores the intricate evidential hurdles and forensic assessment demands inherent in such cases. For UK solicitors, barristers, and expert neurologists, understanding these nuances is critical for robust claim management and fair adjudication.

Understanding Functional Neurological Disorder in a Medico-Legal Context

FND encompasses a range of neurological symptoms – such as paralysis, weakness, seizures, movement disorders, or sensory loss – that are incongruent with recognised neurological disease, yet are genuinely experienced by the patient. In neurological practice, it is generally recognised that FND arises from a complex interplay of biological, psychological, and social factors leading to altered brain functioning, rather than malingering or purely psychological distress. Diagnostic criteria typically require positive neurological signs (e.g., Hoover’s sign for functional leg weakness, entrainment for functional tremor) alongside the exclusion of organic disease. This distinction between functional vs organic neurological conditions is paramount.

Medico-legally, the genuine nature of FND symptoms can be difficult to convey or comprehend, leading to disputes over causation, severity, and prognosis. Unlike a clear stroke where the primary vs secondary injury mechanisms are well-understood and often visible on imaging, FND lacks a discrete lesion. This makes the objective demonstration of injury challenging for legal teams and requires sophisticated explanation from expert witnesses.

Causation Analysis in FND Claims: Unravelling the Triggers

Establishing causation in FND claims is arguably one of the most contentious aspects. While FND is not caused by structural brain damage, it is often triggered or exacerbated by physical injury, psychological trauma, or an acute medical illness. In many medico-legal cases, the central question revolves around whether an alleged negligent event – be it a traumatic injury, medical misadventure, or a period of severe stress – has caused or significantly contributed to the development or persistence of FND symptoms.

Unlike direct neurological harm, such as a traumatic brain injury where the mechanism of injury (e.g., acceleration-deceleration forces leading to axonal shear) is relatively straightforward, FND causation is often indirect and multifactorial. Expert opinion may consider a ‘stress-diathesis model’, where a precipitating event interacts with pre-existing vulnerabilities. The forensic challenge lies in attributing specific functional changes to the alleged event on a balance of probabilities, rather than attributing them to pre-existing conditions or unrelated factors. This necessitates a thorough exploration of the claimant’s pre-morbid history, including any previous neurological or psychological vulnerabilities.

Diagnostic Challenges and the Role of the Neurologist Expert Witness

The diagnosis of FND is a clinical one, requiring expertise to differentiate it from organic neurological diseases and other conditions. Diagnostic challenges are frequent; for instance, distinguishing genuine epileptic seizures from non-epileptic events (PNES), which are a common manifestation of FND, demands careful semiological analysis and often Video-EEG monitoring. Similarly, functional weakness or sensory loss must be meticulously differentiated from conditions like multiple sclerosis or peripheral neuropathies.

In contrast to conditions like acute ischaemic stroke, where the timing and delay impact (e.g., exceeding the thrombolysis window) are clear and measurable, the diagnostic pathway for FND can be prolonged and iterative. Misdiagnosis or delayed diagnosis of FND can have significant medico-legal implications, impacting a claimant’s trust in the medical system and potentially worsening prognosis.

The Expert Neurologist’s Crucial Contribution

The neurologist expert witness plays a pivotal role in these claims. Their responsibilities include:

• Conducting a comprehensive clinical assessment, including a detailed neurological examination focused on identifying positive FND signs.
• Thoroughly reviewing all medical records, including imaging, neurophysiological studies, and psychiatric assessments, to exclude organic pathology.
• Providing a clear differential diagnosis process and justifying the FND diagnosis with robust clinical reasoning.
• Analysing causation, considering the temporal relationship between the alleged event and symptom onset, and accounting for pre-existing vulnerabilities.
• Offering an informed opinion on prognosis, acknowledging the inherent uncertainty in FND.

The expert must articulate complex neurological concepts clearly for a non-medical audience, ensuring that the genuine nature of the symptoms and their impact are understood.

Prognosis, Capacity, and Practical Implications for Solicitors

Prognosis uncertainty in neurological cases is a significant factor in FND. While some individuals experience spontaneous recovery or respond well to targeted therapies (e.g., physiotherapy, psychological support), FND can be chronic and disabling for others. Expert opinion may consider that factors such as symptom duration, presence of comorbidities, and access to appropriate treatment can influence the outcome.

Furthermore, FND can significantly impact a claimant’s daily functioning, leading to loss of employment, increased care needs, and a diminished quality of life. In some severe cases, where FND leads to significant cognitive slowing, executive dysfunction, or profound apathy, considerations regarding capacity and cognitive impairment may also arise, requiring expert assessment in line with the Mental Capacity Act 2005.

For solicitors, navigating FND claims requires a strategic approach informed by neurological expertise. Common pitfalls include underestimating the condition’s genuine impact, oversimplifying causation, or failing to appreciate the nuances of diagnosis. The recent discontinuance highlights the need for a robust and defensible position from the outset.

Practical Implications for Legal Professionals:

• Early Expert Instruction: Engage an experienced neurologist expert witness early in the claim who is proficient in FND medico-legal assessment.
• Comprehensive Record Review: Ensure all medical records, including pre-incident history, are meticulously reviewed to identify predisposing factors or co-existing conditions.
• Understanding Expert Nuances: Work closely with your expert to understand the diagnostic criteria, the scientific basis of FND, and the challenges in establishing causation.
• Manage Expectations: Advise clients realistically about the complexities of FND claims, particularly regarding causation and prognosis.
• Focus on Impact: While causation is key, thoroughly document the functional impact of the FND on the claimant’s life to quantify damages appropriately.

The journey through a Functional Neurological Disorder claim is rarely straightforward. It demands a deep understanding of complex neurological principles, meticulous forensic assessment, and a clear, evidence-based approach from all legal and medical professionals involved. By learning from the challenges of discontinued cases, the medico-legal community can better serve claimants with FND and ensure that these genuinely disabling conditions are fairly and appropriately addressed within the justice system.