[Brain performance and behavior in senile dementias of the Alzheimer type].
Following a brief review of the recent literature on dementia methodological problems in the assessment of intellectual disturbances, psychopathological syndroms and modifications of behaviour in dementia are discussed. The study deals with the course of illness of untreated patients suffering from senile dementia of the Alzheimer's type. Patients were investigated five times during a period of 35 days. Scales used were the SKT-FPB test system (Erzigkeit, 1977), the Sandoz Clinical Assessment Geriatrics (SCAG, Shader et al., 1974) and the Geriatric Rating Scale (GRS, Plutchik et al., 1970). The first test system measures brain performance were the SCAG and the GRS mainly deal with psychopathological and behavioural disturbances. For resp. five factors of SCAG resp. GRS could be separated through hierarchical cluster analysis. No significant difference between the values of the SKT-FPP test system and the two observer rating scales could be found at any time of the study. This also proved right when dementias were separated clinically into mild and severe forms. These two groups could only be differentiated by the SKT-FPP test system, the factor 1 (organic impairment) of the SCAG and the factor 4 (social maladaption) of the GRS. Following a separation of clinically ameliorated, worsened or unchanged patients at the end of the study significant differences could only be found in the values of the FP-standard points and the factors organic impairment, depression and social maladaption in the observer rating scales. The impression, that prognosis of patients with a statistically unstabile course (descriptively assessed by means of the sum of variances) would be different from patients with stabile courses could not be proven. Investigation by correlation statistics of the whole patient groups at the test points showed that the FP-standard points correlated only with the factors social maladaption and organic impairment. It is concluded that according to this data best assessment of the course of illness is by psychometric methods, i.e. the SKT-FPB test system in this study. Observer rating scales, frequently mentioned in the literature seem to be more inconsistent and problematic for the valuation of the course of illness of dementias. They also seem to be in sufficient to evaluate effects of therapy, a fact being of major importance when concerning their frequent use in psychopharmacological trials in demented patients. The study could also show, that the variation in course of illness of patients suffering from senile dementia of the Alzheimer type is so big, that grouping these patients leads to the loss of statistical differences of their illness.