Examining the presence and nature of delusions in Alzheimer's disease and frontotemporal dementia syndromes

Fiona Kumfor, Cheng Tao Liang, Jessica L. Hazelton, Cristian E. Leyton, Cassandra Kaizik, Emma Devenney, Emily Connaughton, Robyn Langdon, Eneida Mioshi, John B. Kwok, Carol Dobson-Stone, Glenda M. Halliday, Olivier Piguet, John R. Hodges, Ramon Landin-Romero

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Abstract

Objectives

Abnormal beliefs and delusions have been reported in some people with dementia, however, the prevalence of delusions, and their neurocognitive basis has been underexplored. This study aimed to examine the presence, severity, content and neural correlates of delusions in a large, well-characterised cohort of dementia patients using a transdiagnostic, cross-sectional approach.

Methods

Four-hundred and eighty-seven people with dementia were recruited: 102 Alzheimer's disease, 136 behavioural-variant frontotemporal dementia, 154 primary progressive aphasia, 29 motor neurone disease, 46 corticobasal syndrome, 20 progressive supranuclear palsy. All patients underwent neuropsychological assessment and brain magnetic resonance imaging, and the Neuropsychiatric Inventory was conducted with an informant, by an experienced clinician.

Results

In our cohort, 48/487 patients (10.8%) had delusions. A diagnosis of behavioural-variant frontotemporal dementia (18.4%) and Alzheimer's disease (11.8%) were associated with increased risk of delusions. A positive gene mutation was observed in 11/27 people with delusions. Individuals with frequent delusions performed worse on the Addenbrooke's Cognitive Examination (p = 0.035), particularly on the orientation/attention (p = 0.022) and memory (p = 0.013) subtests. Voxel-based morphometry analyses found that increased delusional psychopathology was associated with reduced integrity of the right middle frontal gyrus, right planum temporale and left anterior temporal pole.

Conclusion

Our results demonstrate that delusions are relatively common in dementia and uncover a unique cognitive and neural profile associated with the manifestation of delusions. Clinically, delusions may lead to delayed or misdiagnosis. Our results shed light on how to identify individuals at risk of neuropsychiatric features of dementia, a crucial first step to enable targeted symptom management.
Original languageEnglish
Article numberGPS5692
JournalInternational Journal of Geriatric Psychiatry
Volume37
Issue number3
Early online date8 Feb 2022
DOIs
Publication statusPublished - 1 Mar 2022

Keywords

  • Alzheimer's disease
  • C9orf72
  • cognitive impairment
  • frontotemporal dementia
  • primary progressive aphasia
  • psychosis
  • research domain criteria (RDoC)
  • structural imaging

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