Linguistic problems of individuals with agrammatic aphasia are not solely restricted to the grammatical domain: a considerable delay in lexical processing was also found in this clinical population (Prather et al., 1997). It was suggested that language processing abilities of aphasic individuals is predictable from their working memory (WM) capacities (Caspari et al., 1998; Friedmann & Gvion, 2003; Wright & Fergadiotos, 2012), however experimental evidence for that is still sparse.
The goal of the present study was to investigate the time course of lexical ambiguity resolution in healthy individuals and patients with agrammatism as a function of their WM span. We hypothesized that patients’ poorer than overall normal performance could at least partly be explained by their reduced WM capacities. Specifically, patients and healthy low WM span individuals were expected to demonstrate similar processing strategies.
Key characteristics of non-fluent (Broca, motor) aphasia are, among others, verb finding difficulties and effortful speech output. These characteristics are related to different levels of speech production (lexical retrieval and motor execution). This study was aimed at identifying patterns of its reorganization depending on the locus of the linguistic deficit in patients with non-fluent aphasia.
Studies that compare the effects of semantic and phonological naming therapies often demonstrate positive response to both treatment techniques, irrespective of underlying locus of naming deficit. This can be explained by the fact that both tasks include semantic (a picture) as well as phonological (word repetition) information. The therapy effect may, therefore, be just a result of their co-activation, the therapy method itself being irrelevant. However, a typical measure of therapy efficiency assessment is accuracy. We proposed that the difference between therapies may be, nevertheless, revealed by using some additional assessment parameters: activation rate, activation latency and correct response latency.
A core issue in neurolinguistic research is to what extent the language problems that people with aphasia suffer from are specific for their brain damage. Possibly, the processes that require more cognitive resources for the healthy brain are vulnerable in aphasia. A way to tap into unimpaired language processing is to employ event-related potentials (ERPs). This study compares behavioral data from aphasic participants and ERP data from healthy participants on the time reference of verbs in Dutch.
Agrammatic speakers have problems with grammatical encoding and decoding. However, not all syntactic processing are equally problematic: present- time –reference /who-questions/ reﬂexives can be processed by narrow syntax alone and are relatively spared compared to past - time –reference / which-questions/ that need additional access to discourse and information structures to link to their referent outside the clause (Avrutin , 2006). Agrammatic aphasic speakers ﬁnd it more difﬁcult to produce and comprehend verb forms that refer to the past than verb forms that refer to the non-past (Bastiaanse, 2011). The same holds for which-questions compared to who-questions and for pronouns compared to reﬂexives (Avrutin , 2006).