Effects of cholinergic blockade on language in healthy young women. Implications for the cholinergic hypothesis in dementia of the Alzheimer type

Abstract

To investigate the effect of cholinergic blockade on language, 22 healthy young women performed tests of reading, spelling and oral language after a subcutaneous injection of 0.4 or 0.6 mg scopolamine. The results were compared with the performance after 0.6 mg methylscopolamine, which produce no central cholinergic effects. The reading and spelling tests were constructed to evaluate the lexical and phonological strategies for reading and spelling of single words. After scopolamine there were dose-dependent impairments in reading, spelling, verbal fluency and object naming. In 25-60% of the subjects receiving 0.6 mg scopolamine there were clinically significant impairments on tests assessing the lexical and phonological strategies. This pattern is similar to the deficits in reading and spelling observed in patients with dementia of the Alzheimer type. Cholinergic loss may be associated with the language impairments found in dementia of the Alzheimer type.