[Delusional misidentifications. Symptoms and neuropsychological models]. / Wahnhafte Missidentifikationen. Klinik, Vorkommen und neuropsychologische Modelle.

Delusional misidentifications include the Capgras delusion, Fregoli delusion, the delusion of subjective doubles and other less frequent symptoms. A common denominator of these unspecific psychopathological symptoms is the patients' denial of their identity or the convinction that their identity or the identity of relatives has been altered. These delusional symptoms occur in the context of somatic and mental diseases, most frequently in schizophrenia and dementia. According to neuropsychological and neuroanatomical studies delusional misidentifications are facilitated by lesions of the temporo-limbic system leading to an impairment in the affective recognition and reality control. Patients suffering from delusional misidentifications have a higher risk of aggressive behaviour which emphasises their clinical relevance.

Tau and Abeta42 protein in CSF of patients with frontotemporal degeneration.

BACKGROUND: CSF concentrations of tau and beta-amyloid protein-42 (Abeta42) have been extensively studied in AD. Few data are available concerning CSF levels of both proteins in patients with frontotemporal degeneration (FTD). METHODS: The authors investigated CSF tau and Abeta42 concentrations in 34 patients with FTD, 74 patients with AD, and 40 cognitively healthy control subjects. CSF levels of tau and Abeta42 were measured by ELISA. With use of receiver operating characteristic-derived cutoff points and linear discrimination lines, the diagnostic sensitivity and specificity of both markers were determined. RESULTS: CSF tau concentrations were significantly higher in FTD than in control subjects but were significantly lower than in AD. CSF Abeta42 levels were significantly lower in FTD than in control subjects but were significantly higher than in AD. In subjects with FTD, neither tau nor Abeta42 levels correlated with the severity of dementia. The best discrimination between the diagnostic groups was obtained by simultaneous measurement of tau and Abeta42, yielding a sensitivity of 90% at a specificity of 77% (FTD vs controls) and a sensitivity of 85% at a specificity of 85% (FTD vs AD). CONCLUSIONS: In FTD, CSF levels of tau are elevated and Abeta42 levels are decreased. With use of these markers, subjects with FTD can be distinguished from control subjects and from patients with AD with reasonable accuracy.