A Case of Capgras Syndrome With Frontotemporal Dementia.

Capgras syndrome (CS), also called imposter syndrome, is a rare psychiatric condition that is characterized by the delusion that a family relative or close friend has been replaced by an identical imposter. Here, we describe a 69-year-old man with CS who presented to the Kemal Arikan Psychiatry Clinic with an ongoing belief that his wife had been replaced by an identical imposter. MRI showed selective anterior left temporal lobe atrophy. Quantitative EEG showed bilateral frontal and temporal slowing. Neuropsychological profiling identified a broad range of deficits in the areas of naming, executive function, and long-term memory. On the basis of these findings, we diagnosed frontotemporal dementia. This case demonstrates that CS can clinically accompany frontotemporal dementia.

Cognitive neuropsychiatric analysis of an additional large Capgras delusion case series.

INTRODUCTION: Although important to cognitive neuropsychiatry and theories of delusions, Capgras delusion has largely been reported in single case studies. Bell et al. [2017. Uncovering Capgras delusion using a large scale medical records database. British Journal of Psychiatry Open, 3(4), 179-185] previously deployed computational and clinical case identification on a large-scale medical records database to report a case series of 84 individuals with Capgras delusion. We replicated this approach on a new database from a different mental health service provider while additionally examining instances of violence, given previous claims that Capgras is a forensic risk. METHODS: We identified 34 additional cases of Capgras. Delusion phenomenology, clinical characteristics, and presence of lesions detected by neuroimaging were extracted. RESULTS: Although most cases involved misidentification of family members or partners, a notable minority (20.6%) included the misidentification of others. Capgras typically did not present as a monothematic delusion. Few cases had identifiable lesions with no evidence of right-hemisphere bias. There was no evidence of physical violence associated with Capgras. CONCLUSIONS: Findings closely replicate Bell et al. (2017). The majority of Capgras delusion phenomenology conforms to the "dual route" model although a significant minority of cases cannot be explained by this framework.

Abnormal brain glucose metabolism in the delusional misidentification syndromes: a positron emission tomography study in Alzheimer disease.

Brain lesions have been reported with increasing frequency in the delusional misidentification syndromes (DMS). This is the first controlled study to describe DMS regional cerebral metabolic rates of glucose (rCMRglc). We compared rCMRglc (using positron emission tomography) and neuropsychological data in 9 patients with DMS and Alzheimer dementia (AD), 15 AD patients without DMS, and 17 healthy controls. The DMS group differed from the AD group without DMS in having significant hypometabolism in paralimbic (orbitofrontal and cingulate areas bilaterally) and left medial temporal areas, and significant bilateral normalized hypermetabolism in sensory association cortices (superior temporal and inferior parietal) without right left asymmetry. Compared to healthy controls, both AD groups had significant dorso lateral frontal hypometabolism bilaterally. No specific DMS neuropsychological profile was identified. Dysfunctional connections among multimodal association areas, paralimbic structures, and dorsolateral frontal cortex are proposed as the predisposing neural deficit underlying DMS, causing cognitive-perceptual-affective dissonance, which under specific conditions results in "positive" delusion formation.

Neuroanatomical correlates of clinical misidentification and misperception in senile dementia of the Alzheimer type.

BACKGROUND: Impaired frontal lobe and/or nondominant hemisphere lesions have been described in patients with typical misidentification syndromes (e.g., Capgras' syndrome or reduplicative paramnesia) who had various underlying psychiatric or neurologic disorders. In a prospective long-term study, the authors examined computed tomography measurements of patients with senile dementia of the Alzheimer type (DAT) to determine whether the forms of misidentification they suffered might correlate with organic factors. METHOD: One hundred twenty-eight consecutive DAT patients were examined by means of standardized clinical instruments (Mini-Mental State score, CAMCOG, the Benton facial recognition test, the Kendrick object learning test, CAMDEX, and the Geriatric Mental State Schedule) and computed tomography. RESULTS: Of the 128 patients, 40 showed symptoms of misidentification; 25 of them misidentified other people in their homes, 7 misidentified their own mirror images, and 7 misidentified television images as being real. Computer-assisted planimetric computed tomography measurements showed that patients with misidentification syndromes had significantly larger right anterior horn areas of the lateral ventricle and significantly larger left anterior brain areas than did patients without such symptoms. CONCLUSIONS: The authors conclude that an accentuated degeneration of the right frontal lobe (and a relative preservation of the left frontal lobe) may be associated with delusional misidentification symptoms in DAT.

Bilateral atrophy of the frontal and temporal lobes in schizophrenic patients with Capgras syndrome: a case-control study using computed tomography.

The computed tomographic scans of 12 patients with Capgras syndrome and 12 matched controls were blindly assessed. A variety of statistical comparisons between the two groups consistently showed that patients with Capgras syndrome had significantly more bilateral frontal and temporal lobe atrophy. Capgras syndrome may be associated with dysfunction of these areas. Interestingly, all of the index patients had paranoid schizophrenia, and these results suggest the hypothesis that in some schizophrenic patients the presence of Capgras syndrome may be a marker for the coexistence of a focal idiopathic neurodegenerative process that preferentially affects the anterior cerebrum bilaterally.

SPECT data in a case of secondary Capgras delusion.

Capgras' delusion (CD) may be secondary to a neurologic lesion, particularly in the right frontal or occipital regions. A 40-year-old woman with multiple sclerosis underwent SPECT during and after an episode of CD. Analysis during delusion showed an uptake defect in the right parietal cortex with an 11% index of asymmetry (normal: < or = 4%). Post-delusion SPECT showed decreased bifrontal and biparietal cortical uptake indices but a normal index of asymmetry. Functional brain imaging may provide clues to the psychopathology of CD.