Principal component analysis of language performances in Alzheimer's disease.

This report analyzes the performances of a group of 104 mildly to moderately impaired probable Alzheimer's disease patients (Mini Mental Examination 10 to 23) on linguistic tasks exploring written and oral language. A principal component analysis showed a two-factor solution including 14 out of the 15 linguistic tasks. Each factor is characterized by a type of operation required to process language material: "operativeness factor," where verbal material receives a transformation; "transcoding factor," where verbal material is processed without any structural modification. Oral verbal repetition remained isolated from the solution.