Lexical access in Broca's and Wernicke's aphasia: a literature review

Abstract

Aphasia is a language disorder that results from brain injury, impairing the speaker's ability to produce and/or comprehend language (Arantzeta, 2021). The study of this specific language deficit is called aphasiology. Research in the area of aphasiology has been a matter of study for several years. Although various concerns about aphasia could be analysed and explained, as aphasic people can present impairments in different levels of the language such as phonology, lexicon, semantics, morphology, syntax, pragmatics and suprasegmental features (Arantzeta, 2021), it is the aim of this paper to analyse how aphasic people specifically access their lexicon. Throughout this paper, research concerning lexical access in Broca’s and Wernicke’s aphasia will be described, and the development and latest findings during the last years will be shown. With such an aim, classical and contemporary publications will be addressed first, and then what new neuroimaging techniques have contributed to the field will be detailed. In short, this paper analyses how advances in new technologies and the standardization of specific tests and tasks have resulted in the discovery of significant and relevant data within the field of Broca’s and Wernicke’s lexical access. The more classical studies reveal that semantic and phonological factors as well as automatic and controlled processing are worth considering in the lexical access of Broca’s and Wernicke’s aphasic people, based on their atypical results compared to healthy subjects (Baker et al., 1981; Milberg et al., 1987, 1988; Hagoort, 1993). Provided the use of advanced brain imaging techniques and other behavioral methodologies such as the Eye-Tracker, contemporary research has shown that both anterior and posterior brain areas are responsible for lexical access and that lexical competition could be the reason under Broca’s and Wernicke’s impairments in lexical access (DeLeon et al., 2007; Yee et al., 2008; Johnson et al., 2019). In fact, current research has shown that Wernicke’s aphasic people have increased lexical activation, whereas Broca’s aphasic people have reduced lexical activation (Yee et al., 2008).