In civil litigation, particularly in personal injury and clinical negligence claims involving brain injury or cognitive impairment, expert evidence can significantly influence case direction and outcome. Increasingly, courts encourage the instruction of a Single Joint Expert (SJE) where appropriate, in order to promote proportionality, reduce duplication, and ensure impartiality. In such cases, a neuropsychologist may be jointly instructed by both claimant and defendant to provide independent, court-focused evidence.
The role of the neuropsychologist as a Single Joint Expert is distinct from that of a party-instructed expert. While all expert witnesses owe their primary duty to the court, an SJE operates under joint instruction from both sides, reinforcing neutrality from the outset.
The Neuropsychologist’s Role as an SJE
In cases involving traumatic brain injury, stroke, neurodegenerative conditions, or complex psychiatric overlap, neuropsychological assessment provides structured evaluation of cognitive functioning, behaviour, emotional regulation, and functional impact.
Because both parties agree to instruction, the neuropsychologist’s conclusions are often central to narrowing issues in dispute. A carefully reasoned SJE report may clarify whether cognitive impairment is present, its likely cause, and the extent to which it impacts daily functioning.
Promoting Proportionality and Efficiency
The use of a Single Joint Expert can reduce adversarial escalation and avoid the cost of duelling reports. In moderate-value claims or cases where the issues are primarily cognitive rather than surgical, joint instruction may be particularly appropriate.
By providing one comprehensive assessment, the neuropsychologist helps focus the litigation on genuine areas of disagreement rather than conflicting interpretations of similar data. This promotes procedural efficiency while maintaining evidential integrity.
Independence and Impartiality
A neuropsychologist acting as an SJE must maintain clear boundaries. The report must address all relevant questions from both parties, explain methodology transparently, and distinguish carefully between fact, inference, and opinion.
Where limitations exist — such as incomplete records or inconsistent self-report — these must be stated openly. If issues fall outside neuropsychological expertise, referral to an appropriate specialist should be recommended.
The credibility of the SJE rests on objectivity. A balanced opinion that withstands scrutiny from both claimant and defendant strengthens the court’s confidence in the evidence.
Supporting Fair Outcomes
At Medico-Legal Healthcare, our neuropsychologists can act as Single Joint Experts in civil litigation. With a clear understanding of procedural rules and a firm commitment to independence, they deliver court-compliant reports that support balanced, efficient, and fair resolution of complex cognitive claims.