A longitudinal study of sentence comprehension difficulty in primary progressive aphasia

Context: Patients with primary progressive aphasia have sentence comprehension difficulty, but the longitudinal course of this deficit has not been investigated. Objective: To determine how grammatical, single word meaning, and working memory factors contribute to longitudinal decline of sentence comprehension in primary progressive aphasia. We hypothesised partially distinct patterns of sentence comprehension difficulty in subgroups of patients with progressive non-fluent aphasia (PNFA) and semantic dementia (SD). Design: Cohort. Setting: Institutional out patient referral centre. Patients: PNFA (n = 14), SD (n = 10). Main outcome measure: Sentence comprehension accuracy. Results: PNFA patients were significantly impaired at understanding grammatically complex sentences when first seen, and this was more evident than impairment of their comprehension of grammatically simple sentences (p