Part 35 Compliance in Neuropsychological Reports: Common Pitfalls for Instructing Solicitors

When instructing a neuropsychologist in a medicolegal context, compliance with Part 35 of the Civil Procedure Rules is essential. Even a clinically sound report can be undermined if procedural requirements are not met, potentially weakening otherwise robust evidence.

This article highlights common Part 35 pitfalls in neuropsychological instruction and reporting, and how solicitors can avoid them — particularly in cases across Devon and Cornwall, where access to specialist expertise may require early planning.

The Neuropsychologist’s Duty to the Court

Under Part 35, a neuropsychologist’s primary duty is to the court, not to the instructing party. This must be explicitly acknowledged within the report.

Common issues include:

• Failure to clearly state the duty to the court

• Overly advocacy-based language

• Insufficient balance when addressing disputed issues

A properly instructed medicolegal neuropsychologist will demonstrate independence, address evidence that does not support the claimant’s case, and clearly distinguish fact from opinion.

Methodology and Transparency

Neuropsychological evidence must be methodologically sound and transparent.

A Part 35–compliant report should:

• Identify all assessment tools used

• Explain why those measures were selected

• Address test validity and effort

• Acknowledge limitations of the assessment

Where methodology is unclear or unexplained, opposing parties may argue that conclusions are unsupported or speculative.

Addressing Symptom Validity and Reliability

In many medicolegal cases, especially those involving mild traumatic brain injury or disputed cognitive complaints, symptom validity is a central issue.

Failure to address effort, consistency, and reliability can be a significant Part 35 weakness. A defensible neuropsychological report should explicitly consider these factors and explain how they inform the overall opinion.

Joint Instruction and Single Joint Experts

Where a neuropsychologist is instructed jointly, additional care is required to ensure:

• Questions are agreed and neutral

• The scope of the report is clearly defined

• Both parties understand what the expert will and will not address

Poorly managed joint instructions can create unnecessary procedural disputes.

Conclusion

Part 35 compliance is not a technicality — it is fundamental to the admissibility and weight of neuropsychological evidence. Solicitors who instruct experienced medicolegal neuropsychologists and provide clear, legally informed instructions significantly reduce the risk of challenge.

Early, structured instruction is particularly important in regions such as Devon and Cornwall, where timely access to specialist expertise can materially affect case progression.