Dementia and Testamentary Capacity: When to Instruct a Neurologist Over a Psychiatrist

Disputes over testamentary capacity in individuals with dementia present unique challenges in medico-legal practice. While psychiatrists are commonly instructed to assess capacity, there are circumstances where a neurologist’s expertise is essential. This article examines the clinical and legal frameworks guiding this decision, helping legal professionals determine when to instruct a neurologist in dementia-related cases.

The Legal Framework for Testamentary Capacity

The legal test for testamentary capacity in England and Wales is established by the Banks v Goodfellow (1870) criteria, supplemented by the Mental Capacity Act 2005. To execute a valid will, the testator must:

• Understand the nature of making a will and its effects;
• Understand the extent of the property being disposed of;
• Comprehend and appreciate the claims to which they ought to give effect; and
• Not be affected by any disorder of the mind that influences their decisions.

In dementia cases, the fourth criterion often becomes the focal point. Dementia is a syndrome characterised by progressive cognitive decline, with varying presentations depending on its aetiology. This variability makes neurological expertise critical in complex cases.

Dementia: A Neurological Perspective

Dementia arises from various neurological conditions, each with distinct clinical trajectories:

• Alzheimer’s disease: Progressive memory loss and cognitive decline due to amyloid plaques and neurofibrillary tangles.
• Vascular dementia: Reduced blood flow to the brain, often following strokes or TIAs, with stepwise progression.
• Lewy body dementia: Fluctuating cognition, visual hallucinations, and Parkinsonian symptoms.
• Frontotemporal dementia (FTD): Personality and behavioural changes, with relative preservation of memory in early stages.
• Mixed dementia: Combination of Alzheimer’s and vascular dementia, common in older adults.

The type of dementia significantly influences testamentary capacity. For example, early-stage Alzheimer’s may affect recall of assets, while FTD may raise concerns about undue influence due to behavioural changes.

When to Instruct a Neurologist

Consider instructing a neurologist in these scenarios:

1. Complex or Atypical Presentations

Neurologists provide clarity in cases where dementia presentation is atypical or diagnosis is unclear. For example:

• Fluctuating cognition in suspected Lewy body dementia may be misinterpreted in psychiatric assessments.
• Behavioural changes in FTD may not be fully appreciated without neurological input.

Neurologists can interpret neuroimaging (MRI/CT scans) and biomarkers to confirm diagnoses and their capacity implications.

2. Neurological Comorbidities

Coexisting conditions like Parkinson’s disease, stroke, or traumatic brain injury complicate capacity assessments. A neurologist can:

• Assess how comorbidities interact with dementia.
• Differentiate between pre-existing dementia and post-traumatic cognitive impairment.

This is particularly relevant in cases where cognitive function may be compromised by both dementia and trauma history.

3. Disputes Over Dementia Progression

In contentious probate cases, neurologists can:

• Review medical records to establish symptom timelines.
• Interpret diagnostic tests to determine cognitive decline rates.
• Opine on whether capacity at will execution aligned with neurological condition.

4. Multi-Disciplinary Cases

Complex cases may require both neurologists and psychiatrists. For example:

• A claimant with dementia and depression may need psychiatric assessment for mental health impact alongside neurological evaluation.
• Cases involving alleged abuse may require neurological assessment of cognitive deficits and psychiatric evaluation of trauma-related symptoms.

Under CPR Part 35, this multi-disciplinary approach strengthens evidential basis while maintaining expert independence.

Common Pitfalls in Capacity Assessments

1. Overreliance on Screening Tools

Tools like MMSE or MoCA have limitations:

• May not detect early-stage or atypical dementia.
• Do not assess executive function critical for testamentary capacity.
• Can be influenced by education level or cultural background.

Neurologists provide nuanced assessments incorporating clinical examination and detailed cognitive testing.

2. Fluctuating Cognition

Dementia, particularly Lewy body dementia, may present with significant cognitive fluctuations. Neurologists can:

• Review records to identify fluctuation patterns.
• Conduct serial assessments to evaluate consistency.
• Opine on whether capacity at will execution was representative.

3. Behavioural Symptom Misinterpretation

Behavioural symptoms may be misattributed:

• Apathy in FTD may be mistaken for depression.
• Disinhibition may be misattributed to personality rather than frontal lobe dysfunction.

Neurologists differentiate between neurological and psychiatric origins of behavioural symptoms.

4. Sensory or Motor Impairments

Neurologists can:

• Assess whether impairments contribute to apparent cognitive deficits.
• Recommend assessment adaptations to ensure accurate evaluation.

Practical Guidance for Solicitors

When to Instruct a Neurologist

Consider a neurologist when:

• Dementia diagnosis is unclear or atypical.
• Coexisting neurological conditions are present.
• There are disputes over dementia onset or progression.
• Complex cognitive or behavioural symptoms require specialised assessment.

Records to Provide

Ensure the neurologist receives:

• Comprehensive medical records (GP notes, hospital admissions).
• Neuroimaging reports (MRI/CT/PET scans).
• Cognitive screening results (MMSE/MoCA).
• Previous neurological/psychiatric assessments.
• Witness statements describing cognitive/behavioural symptoms.

What to Expect from the Report

A neurologist’s report should address:

• Detailed medical history review focusing on neurological symptoms.
• Interpretation of diagnostic tests with reference to underlying pathology.
• Assessment of cognitive function relevant to testamentary capacity.
• Opinion on cognitive function consistency with neurological condition at will execution.
• Recommendations for further assessments or adaptations if needed.

Preparing the Claimant

To ensure a trauma-informed approach:

• Explain the assessment purpose in clear terms.
• Allow a trusted person to be present if desired.
• Conduct the assessment in a familiar, comfortable environment.
• Be mindful of fatigue and cognitive limitations, allowing breaks as needed.

Conclusion

In dementia-related testamentary capacity cases, neurologists provide critical insights into cognitive function and its capacity implications. While psychiatrists assess functional aspects of capacity, neurologists offer specialised expertise in underlying neurological pathology. Understanding when to instruct a neurologist and how to prepare for assessments ensures thorough, trauma-informed evaluations that strengthen medico-legal cases.