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Delusional misidentification in Alzheimer's disease: a summary of clinical and biological aspects
H Förstl1, C Besthorn, A Burns
1Central Institute of Mental Health, Mannheim, Germany.
Abstract:
Delusional misidentification symptoms (DMS) are common in Alzheimer's disease (AD) and they are frequent sources of serious distress for patients and particularly caregivers. We observed DMS in around 30% of the patients with moderate to severe AD in two independent prospective studies; the Capgras type, phantom boarder, mirror and TV DMS were found most frequently. Patients with DMS showed increased EEG delta-power over the right hemisphere, their CT scans showed more severe right frontal lobe atrophy, and the number of their pyramidal cells in area CA1 was lower than in the patients without DMS. This may indicate that the development of DMS in AD can be promoted by certain patterns of brain degeneration which affect systems relevant to the recognition and updating of memories, while verbal skills may initially be left largely intact.
Insights
Delusional misidentification symptoms (DMS) are common in Alzheimer's disease (AD), affecting 30% of patients. Brain degeneration in specific areas may underlie these distressing symptoms in AD patients.
Area of Science:
- Neuroscience
- Neurology
- Geriatric Psychiatry
Background:
- Delusional misidentification symptoms (DMS) frequently occur in Alzheimer's disease (AD).
- These symptoms cause significant distress for patients and caregivers.
- Common DMS types include Capgras, phantom boarder, mirror, and TV delusions.
Purpose of the Study:
- To investigate the prevalence and potential neurological underpinnings of DMS in Alzheimer's disease.
- To identify specific patterns of brain degeneration associated with DMS in AD patients.
Main Methods:
- Prospective observation of patients with moderate to severe AD across two independent studies.
- Analysis of electroencephalogram (EEG) data for delta-power.
- Review of computed tomography (CT) scans for brain atrophy.
- Histopathological examination of pyramidal cells in hippocampal area CA1.
Main Results:
- DMS were observed in approximately 30% of AD patients studied.
- Patients with DMS exhibited increased right hemisphere EEG delta-power.
- More severe right frontal lobe atrophy was noted on CT scans of patients with DMS.
- Reduced number of pyramidal cells in area CA1 was found in patients with DMS compared to those without.
Conclusions:
- Specific patterns of brain degeneration, particularly affecting memory recognition and updating systems, may contribute to DMS development in AD.
- These neurological changes might occur while verbal skills remain relatively preserved.
- Findings suggest a link between localized brain atrophy and neurodegeneration and the manifestation of DMS in Alzheimer's disease.