Common pattern of language impairment in vascular dementia and in Alzheimer disease.

The authors studied language performance patterns in early stages of vascular dementia and Alzheimer disease. The objective was to clarify to what extent dissolution of language in vascular dementia is similar to that in Alzheimer disease. Both structured language tests (comprehension, repetition, reading, and naming tasks) and nonstructured language tests (object and picture description) were employed. The structured tasks evidenced impairment on complex auditory comprehension and on picture naming for both dementia groups, whereas oral reading and single word repetition did not differentiate the patients from matched control subjects. On the unstructured narrative tasks, both patient groups showed normal fluency, but content analysis revealed that the patients with dementia produced fewer semantic units (themes) than the control subjects. In summary, both patient groups showed impairment, specifically on semantically mediated language tasks. According to the present results, language impairment in vascular dementia resembles that observed in Alzheimer disease. Semantically mediated functions are among the most sensitive language measures in differentiating early stages of both vascular dementia and Alzheimer disease from normal aging.