Clinical and neuroimaging characteristics of patients with primary progressive aphasia

Abstract

Objective To identify the clinical profile and the neuroimaging characteristics of patients with primary progressive aphasia (PPA). Methods Of 32 patients diagnosed as PPA in the Memory Clinic of Tianjin Huanhu Hospital between April 2011 and October 2014, 16 patients with semantic dementia (SD), 15 patients with progressive non-fluent aphasia (PNFA), 1 patient with logopenic progressive aphasia (LPA) were identified. Clinical data of the patients were collected. Cognitive function was measured by the Mini-Mental State Examination, Montreal Cognitive Assessment, Clinical Dementia Rating and Boston naming test. Brain magnetic resonance imaging was conducted to evaluate the cortex atrophy and medial temporal lobe atrophy. The 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) and Pittsburg Compound B (PiB) PET cerebral imaging were performed in patients with atypical clinical and MRI demonstrations. Results The onset age was 40 to 69 (59.6±7.0) years, and 24 patients (75%) were younger than 65 years. The ratio of male to female was 17 to 15. Seven patients (22%) have positive family history. The average onset age of SD patients was younger than PNFA patients. The Boston naming test and verbal fluency test had a high sensitivity in PPA patients, and the scores of SD patients were lower than PNFA patients. Twenty three of the patients had memory loss. Patients with SD showed bitemporal lobe atrophy, left temporal lobe atrophy. PFNA patients mainly manifested as left frontotemporal, bilateral frontotemporal atrophy on MRI scan. Five patients (3 PNFA, 2 SD) with no obvious atrophy on head MRI had FDG-PET scan. Among the three PNFA patients, one showed hypometabolism on the left frontal, left thalamus, left anterior cingulate, and two showed hypometabolism on bilateral frontal, insula, thalamus, caudate nucleus, anterior cingulate, and left temporal lobe. Among the two SD patients, one showed left temporal, left caudate nucleus hypometabolism, and one showed bilateral temporal (left > right), left frontal, left insula, left occipital hypometabolism. One LPA patient showed right temporal, parietal lobe, insula, and left parietal lobe hypometabolism. LPA patients showed cortical amyloid deposition. Conclusions PPA patients have younger onset age. The majority of patients have memory loss. Brain atrophy and hypometabolism are mainly on the left frontotemporal lobe. LPA patients show deposition of amyloid protein. Key words: Primary progressive aphasia; Dementia; Clinical neuroimaging