Language Processing in Neurodegenerative Diseases:Semantic, Phonological, and Grammatical Impairments in Alzheimer’s Disease, Parkinson’s Disease, and Frontotemporal Lobar Degeneration – A Linguistic Overview

Disorders of language and/or communicative abilities in neurodegenerative diseases are a common phenomenon. Over the past fewdecades, there has been a growing interest in language performance connected to these diseases. To date, studies in the fi eld of language impairments in Alzheimer’s disease (AD), Parkinson’s disease (PD), and frontotemporal lobar degeneration (FTLD) have focused mainly on particular aspects of language processing in the isolated disease or on comparing certain language tasks in two neurodegenerative diseases. To enable a better understanding and comparison of the underlying linguistic defi cits in all three disorders, this paper focuses on phonological, semantic, and grammatical processing in each of the disorders. A review of the literature on language processing defi cits reveals that phonological, semantic, and grammatical processing is impaired in the early stages of AD, PD, and FTLD, and that the underlying defi cits are sometimes linguistic in nature. Language disorders, however, may also refl ect cognitive defi cits, such as short-term verbal memory impairments,attention defi cits, and reduced switching capacities, all of which have an impact on language processin