Reading difficulties in primary progressive aphasia in a regular language-speaking cohort of patients

- Agrammatic and logopenic aphasia were impaired in nonwords reading.
- Semantic aphasia was impaired in exception words reading.
- The use of words without stress marks was the best way to examine the lexical route.
- Left frontal and left parieto-temporal metabolism was associated to nonwords reading.
- Anterior temporal lobe was related to exception words reading.

Reading impairment is an important feature in Primary Progressive Aphasia (PPA). The Spanish orthography entails completely regular spelling to sound correspondences, so reading disorders may be different to English. In the current study, reading, phonological and semantic abilities of 35 patients with the three variants of PPA, and 13 healthy volunteers were assessed. Brain metabolism was concomitantly obtained from each participant using 18F-fluorodeoxyglucose positron emission tomography imaging. Two main patterns of impairment were identified: difficulties in nonwords reading with preservation of exception words in agrammatic and logopenic aphasia, and the inverse pattern in semantic dementia. Left frontal and left parietotemporal regions were associated to nonwords reading, while the anterior temporal lobe was related to reading of exception words. These results support the usefulness of examining reading abilities in the differential diagnosis of PPA variants, and suggest potential types of words that could be used in Spanish to assess these patients.