Speech and Language characteristics of Kannada and Hindi speaking individuals with Primary Progressive Aphasia

Abstract

AbstractBackgroundLinguistic typology plays an important role in identifying clinical markers of language deficits that characterise Primary Progressive Aphasia (PPA). The current International criteria to diagnose PPA were primarily developed for English. Typological characteristics of Indian languages however differ from English in their morpho‐syntactic complexity, a flexible‐word order, richer morphology, ‘pro‐drop’ languages with absence of prepositions and transparent orthography. We aimed to develop a novel test in Kannada (Dravidian) and Hindi (Indo‐Aryan) to identify language deficits in Indian language speakers with PPA.MethodThe speech‐language test systematically developed for Kannada and Hindi consisted of unique tasks for syntax, semantics, phonology, motor speech and working memory. Participants underwent assessment of cognition and language with Addenbrooke’s Cognitive Examination‐III, Western Aphasia Battery‐Revised and Indian Semantic Memory Battery (ISMB) in addition to the novel test.ResultsOf 26 patients with PPA (Kannada 13, Hindi 13), 15 had non‐fluent variant (nfvPPA), 8 semantic variant (svPPA) and 3 logopenic variant (lvPPA). On the novel test, PPA had higher phonological, motor speech, syntactic and semantic errors compared to 60 controls. nfvPPA had higher phonological, motor speech and syntactic errors and lesser semantic errors compared to svPPA. Semantic and working memory errors discriminated between nfvPPA and svPPA. On qualitative analysis, 5 patients of nfvPPA had significant apraxia of speech. The other 10 had a unique syntactic profile: agrammatism was not prominent in their spontaneous speech and picture description. Sentences were relatively fluent, complete and sufficient for functional communication. The consistent abnormality observed was a reduction in overall length of utterance. Agrammatisms such as inappropriate use of case markers were restricted to specific tests of syntax. svPPA patients had increased verbal output and prominent paragrammatisms. Testing for surface dyslexia was not relevant due to the orthographic transparency of Indian languages.ConclusionThe novel language test for evaluation of Indian speakers of PPA revealed unique findings for diagnosis of nfvPPA. Reduction in length of utterances and lack of prominent agrammatism was a consistent clinical marker and owes itself to morpho‐syntactic complexity of Indian languages. Our study emphasises the need to account for linguistic typology in diagnosis of PPA.