Determining Litigation Capacity: A Neurology-Led Perspective on Mental Capacity Records

In civil litigation, the capacity of a claimant to conduct proceedings is a foundational requirement. Where a neurological condition, such as a traumatic brain injury (TBI) or neurodegenerative disease, is a central feature of the claim, the assessment of litigation capacity necessitates a nuanced understanding of cognitive domain deficits, behavioural sequelae, and the functional implications of neurological impairment. The role of the neurology consultant is to provide the court with an objective, evidence-based assessment of whether the claimant possesses the functional capacity to understand, retain, and weigh information relevant to the decisions in their case, and to communicate those decisions effectively.

Neurological Determinants of Capacity

Capacity is decision-specific and time-specific under the Mental Capacity Act 2005. In neurology-led assessments, the focus is on identifying objective neurological deficits that correlate with the functional test of capacity. For example, in cases involving TBI, clinicians evaluate the impact of frontal lobe dysfunction on executive function, which may impair an individual’s ability to appreciate the consequences of litigation decisions. Similarly, in neurodegenerative conditions, a formal evaluation of legal decision-making ability helps distinguish between early-stage cognitive decline and more advanced pathology that demonstrably prevents the claimant from weighing complex legal concepts.

Assessing capacity in the context of neurological conditions involves:

• Quantitative cognitive assessment, noting that psychometric scores alone do not equate to a capacity finding.
• Evaluating the Glasgow Outcome Scale or similar functional measures in TBI to contextualise long-term cognitive and behavioural limitations.
• Reviewing longitudinal imaging and clinical records to assess whether cognitive deficits are consistent with known neurological trajectories.
• Consideration of behavioural sequelae, which may manifest as impulsivity or poor insight, potentially impacting the claimant’s ability to work with legal representatives.

Medico-legal Disputes and Symptom Validity

A challenge in neurology-led capacity reporting arises in cases involving Functional Neurological Disorder (FND) or subjective symptom reporting post-concussion. Where diagnostic criteria for FND are met, the expert should distinguish between organic neurological impairment and symptom validity issues. Medico-legal disputes often centre on whether alleged capacity deficits are secondary to an organic pathology or are influenced by non-neurological factors. Under the principles of clinical practice, the expert’s opinion must be logically defensible, avoiding diagnostic overreach where objective neurological evidence is absent.

The Role of the Expert Witness and Procedural Compliance

In accordance with CPR Part 35, the expert’s overriding duty is to the court. When preparing reports, the expert must ensure their opinion on capacity is grounded in the available clinical evidence. If the claim proceeds to court, the expert may be required to participate in a discussion under CPR 35.12 to narrow issues with a counterpart. It is important to distinguish these discussions from the role of a single joint expert appointed under CPR 35.7, who has specific duties under CPR 35.8 regarding the instruction process. Any questions posed to an expert under CPR 35.6 must adhere to the proportionality requirements of the rules.

For solicitors, the quality of instruction influences the efficiency and accuracy of the report. Instructing parties should provide a comprehensive, chronologically organised bundle, including relevant GP and specialist records, which allows the neurologist to evaluate the baseline health of the claimant. In cases of clinical negligence, the neurology expert must be able to demonstrate whether the neurological outcome is a direct consequence of the alleged negligence, consistent with the but-for analysis, or if it relates to pre-existing conditions that trigger considerations of apportionment.