Semantic variant Primary Progressive Aphasia: Additional semantic features in Chinese language users

Abstract

AbstractBackgroundTo date, most literature on Primary Progressive Aphasia (PPA) has been based on English language users. Yet, there are more than 7,000 living languages worldwide with vast heterogeneities in their linguistic features. Contrary to English language, Chinese language is a classifier language in which it is grammatically mandatory to have classifiers present between numerals and nouns. In addition, Chinese characters typically have an abundance of homophones (i.e., words with same pronunciation but vary in orthography and meaning) and heteronyms (i.e., words with same orthography but vary in meaning and pronunciation). Chinese language users rely on semantic knowledge to identify the accurate classifiers, homophones, and heteronym pronunciations. Thus, we hypothesize that Chinese‐speaking semantic variant (sv) PPA patients have difficulties producing classifiers, homophones, and heteronyms.MethodTo assess classifier production, participants are presented with pictures of nouns. Participants are first tasked with producing noun‐specific classifiers spontaneously. If failed, they are presented with four classifiers to select. To evaluate homophone selection skills, participants are shown short sentences with one character/word removed. They are then tasked to complete the sentences by choosing one of the four homophones presented. For heteronym reading, participants are asked to read out loud Chinese compound words with heteronyms (e.g., “windmill” and “wind up”).ResultWe recruited 22 controls and 47 PPA individuals (12 svPPA, 10 nonfluent variant (nfv) PPA and 25 logopenic variant (lv) PPA). In classifier production test, svPPA and lvPPA patients produce fewer accurate classifiers (p<0.0001, p = 0.001), with svPPA showing least improvement when presented with multiple choices (p = 0.003). In homophone selection test, svPPA and lvPPA scored lower than controls (p<0.0001 and p = 0.007). For heteronym reading test, svPPA showed the lowest performance when tasked with reading heteronym characters (p = 0.001). Using voxel‐based morphometry, we noted that the ability to produce classifiers, read heteronyms and identify heteronyms are correlated with grey matter volumetric changes over the anterior portion of the left temporal lobe and fusiform gyri, brain regions associated with language semantic functions.ConclusionPPA symptomatology may vary across languages. Thus, studying PPA symptoms via a linguistically diverse approach potentially provides a more comprehensive understanding to the syndrome.