Psychometric characteristics of the Alzheimer's Disease Assessment Scale (ADAS) were examined on the basis of data from 440 patients with dementia of the Alzheimer type that were collected before treatment in a multicenter clinical drug trial. Coefficients of internal consistency of above .SO for the cognitive (ADAS-Cog) and the noncognitive section (ADAS-Noncog) indicated a high degree of homogeneity of item contents within the two assessment domains. Test-retest reliability was estimated to be .93, .98, and .96 for ADAS-Cog, ADAS-Noncog, and the total score (ADAS-Total), respectively. Reliably detectable individual changes, which were derived from the reliability estimates, were 7,3, and 8 points for ADAS-Cog, ADAS-Noncog, and ADAS-Total, in that order. Factor analysis and correlations with MMSE, SKT, and NOSGER scores support the validity of the ADAS-Cog and ADAS-Noncog scores with regard to the cognitive and thenoncognitiveassessment domains. The ADASsummary scores, almost all of the cognitive items, and someof the noncognitive items discriminated significantly between stages of severity of dementia, as classified independently by MMSE and SKT scores.The Alzheimer's Disease Assessment Scale (ADAS; Rosen et al., 1984) was designed specifically to evaluate the severity of cognitive and noncognitive symptoms in patients with dementia of the Alzheimer type (DAT). The scale con-

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Two doses of idebenone were studied in a prospective, randomized, double-blind, placebo-controlled multicentre study in patients suffering from dementia of the Alzheimer type (DAT) of mild to moderate degree. Diagnosis was based on DSM-III-R (primary degenerative dementia) and NINCDS-ADRDA criteria (probable Alzheimer’s disease). A total of 300 patients were randomized to either placebo, idebenone 30 mg t.i.d. or 90 mg t.i.d. (n = 100, each) and treated for 6 months. The primary outcome measure was the total score of the Alzheimer’s Disease Assessment Scale (ADAS-Total) at month 6. Secondary outcome measures were the ADAS cognitive (ADAS-Cog) and non-cognitive scores (ADAS-Noncog), the clinical global response (CGI-Improve-ment), the MMSE, the Digit Symbol Substitution test (DSS) and several scales for the assessment of daily activities (the self- and observer-rating scales NAA and NAB of the Nuremberg Age Inventory NAI and Greene’s Assessment). Safety parameters were adverse events, vital signs, ECG and clinical laboratory parameters. Clinical and psychometric evaluations were performed at baseline, and after 1, 3 and 6 months of treatment. After month 6 idebenone 90 mg t.i.d. showed statistically significant improvement in the primary efficacy variable ADAS-Total and in ADAS-Cog. An analysis of therapy responders performed for 3 outcome measures (CGI-global improvement, ADAS-Cog, ADAS-Noncog), selected to represent different domains of assessment, revealed significant superiority of idebenone 90 mg t.i.d. with respect to placebo in each of the 3 variables and in the concordance of responses across the 3 measures. Exploratory results for a subgroup of patients (ADAS-Total > 20) showed dose-related superiority of idebenone additionally on ADAS-Noncog and the CGI-Improvement scale. Safety results were inconspicuous for all assessments. The study results demonstrate the efficacy and safety of idebenone in the treatment of DAT patients.

This study evaluated the safety and efficacy of idebenone vs. tacrine in a prospective, randomized, double-blind, parallel-group multicenter study in patients suffering from dementia of the Alzheimer type (DAT) of mild to moderate degree. Diagnosis was based on DSM-III-R (primary degenerative dementia) and NINCDS-ADRDA criteria (probable Alzheimer's disease). A total of 203 patients of both sexes aged between 40 and 90 years were randomized to either idebenone 360 mg/day (n = 104) or tacrine up to 160 mg/day (n = 99) and treated for 60 weeks. The primary outcome measure was the Efficacy Index Score (EIS). The EIS combines dropout as well as the relevant improvements individually across the three levels of assessment (cognitive function, activities of daily living, global function). Secondary outcome measures were the ADAS-Cog score, the NOSGER-IADL score and the clinical global response (CGI-Improvement). After 60 weeks of treatment, 28.8 % of the patients randomized to idebenone, but only 9.1 % of the patients randomized to tacrine were still on the drug. In the LOCF analysis, 50 % of the patients randomized to idebenone but only 39.4 % of the patients randomized to tacrine showed an improvement in the Efficacy Index Score or at least one of the secondary outcome variables. The primary efficacy measurement was the change of the Efficacy Index Score from baseline to the assessment after 60 weeks treatment. The analysis was done on intention-to-treat (ITT) in a before-and-after test design. Patients randomized to idebenone showed a higher benefit from treatment than patients randomized to tacrine. We conclude that the benefit-risk ratio is favorable for idebenone compared to tacrine, and furthermore, that this ratio is likely to be similar when comparing idebenone to other cholinesterase inhibitors.

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