Comparison of Alzheimer Disease Patients and Normal Elder in Relationship between Working Memory and Sentence Comprehension

The aim of this study was to investigate the relation between working memory and sentence comprehension. Patients with Dementia of the Alzheimer´s type (DAT) and matched older volunteers were tested on a battery of working memory tests, as well as on test of sentence comprehension. This is a cross-sectional study. Statistical population included all patients with Alzheimer disease who were registered in the center of Alzheimer (Imam Ali) in Tehran.10 patients randomly were selected among them, according to inclusive and exclusive criteria. For data collection, epidemiological information questionnaire, Mental Mini State Examination (MMSE), working memory tests and sentence comprehension were applied. Data were analyzed by Independent T-test and correlation analyses. Patients had impaired central executive processes in working memory (P=0.006), but showed normal effects of phonological and articulatory variables on span(P=0.480). On the sentence comprehension tasks (simple and complicated sentences), DAT patients showed significant differences with their peers (simple s. P=0.001, complicated s. P= 0.004). Impairment in the central executive processes of working memory in DAT patients was correlated with the complicated sentences on the sentence comprehension tasks. The results suggest that patients with DAT have working memory impairments that are related to their ability to map the meaning on sentences on to depictions of events in the world.