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.


METHODS
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.
Förstl
H
H
Section of Old Age Psychiatry, Institute of Psychiatry, London, United Kingdom.
Burns
A
A
Jacoby
R
R
Levy
R
R
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000523:psychology*; D001921:Brain / Q000000981:diagnostic imaging*; D002194:Capgras Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002552:Cerebral Ventricles / Q000473:pathology; D003702:Delusions / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003936:Diagnosis, Computer-Assisted; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D014057:Tomography, X-Ray Computed