[A study of the effect of donepezil hydrochloride on cognitive function in patients with dementia of Alzheimer's type using WAIS-R].

: The present study aimed to assess the initial effects of donepezil hydrochloride (DPZ) on various aspects of cognitive function in patients with dementia of Alzheimer's type (DAT) using the Japanese version of the Wechsler Adult Intelligence Scale-Revised (WAIS-R). DPZ was administered to 47 patients with mild-to-moderate DAT (D group). The control group comprised 61 patients who had been followed up before DPZ was released for use (C group). Both groups underwent WAIS-R testing, before and after 10 months of treatment with DPZ for group D, and at time of diagnosis of DAT and 10 months later for group C. D and C groups did not differ significantly in terms of gender ratio, years of education, age at onset of DAT, age at administration of DPZ or at diagnosis of DAT, severity of dementia, MMSE score, presence of behavioral and psychological symptoms of dementia, concomitant use of psychotropic medication, or initiation of rehabilitation. No significant differences were found between D and C groups in verbal (V), performance (P) or full-scale (F) intelligence quotient (IQ), or in six verbal subtest scores of VIQ and five performance subtest scores of PIQ on WAIS-R, before administration of DPZ or at diagnosis of DAT. For differences between each score on WAIS-R at diagnosis of DAT or before administration of DPZ and 10 months later, DPZ inhibited decreases in FIQ and in VIQ, PIQ, vocabulary, similarities, picture arrangement and object assembly subtest scores on WAIS-R. These indices are related to concept formation and abstract thinking, which form part of executive function. DPZ effectively prevented decline of cognitive function, particularly executive function, in patients with DAT.