Delusional misidentification and subsequent dementia: a clinical and neuropathological study

Area of Science:

• Neurology
• Neuroscience
• Pathology

Background:

• Capgras delusion, a rare neuropsychiatric condition, involves the delusion that a familiar person has been replaced by an imposter.
• The etiology of psychotic symptoms, particularly delusions, in the context of dementia remains complex and multifactorial.

Observation:

• An 81-year-old male presented with Capgras delusion, initially without dementia, but later developed dementia and died 5 years post-presentation.
• Neuropathological examination revealed diffuse beta-amyloid plaques in the cortex, cortical and subcortical Lewy bodies, and absence of cortical neurofibrillary tangles.
• Significant findings included numerous small lacunar infarcts in the frontal and parietal white matter, attributed to arteriosclerotic and hypertensive vascular changes.

Findings:

• Beta-amyloid plaques were detected using specific antibodies, indicating a possible contribution to the observed pathology.
• The presence of Lewy bodies suggests a potential overlap or coexistence of pathologies.
• White-matter lesions, specifically lacunar infarcts, were prominently observed in the frontal and parietal regions.

Implications:

• This case highlights the potential role of white-matter lesions and vascular changes in the pathogenesis of delusions, such as Capgras delusion.
• The findings suggest that white-matter integrity may be crucial for cognitive and psychiatric stability, even in the presence of other neuropathologies.
• Further research into the contribution of cerebrovascular disease to the development of psychotic symptoms in dementia is warranted.