Lexical ambiguity resolution as a function of working memory: eye-tracking data from agrammatic and healthy individuals
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.
Aphasia, a language impairment following stroke or brain trauma, is normally manifested behaviorally. Patients with the so-called non-fluent aphasia experience major difficulties at the level of morphosyntax (that is, producing and comprehending complex morphology and syntax). In contrast, patients with fluent aphasia predominantly show problems at the lexical-semantic level (that is, accessing word forms and lexical semantics). However, a few studies have proven that the language deficit in patients with aphasia is expressed not only in their linguistic performance, but also in specific electrophysiological responses.
In healthy individuals, incongruencies at different linguistic levels cause distinct event-related brain potentials (ERPs) registrated at the scalp. Syntactic incongruency elicits the ELAN and the P600 potentials, lexical-semantic incongruency elicits the N400 potential. Critically, in standard for those potentials linguistic contexts the lack of N400 was reported for fluent patients, while the lack of the ELAN and a reduced and delayed P600 – for non-fluent patients (Friederici et al. 1998, Wassenaar and Hagoort 2005). These findings support the idea of electrophysiological brain mapping on specific linguistic problems observed in different aphasia types.
The study was aimed at further investigating electrophysiological evidence for the suggestion that spoken sentence comprehension problems in individuals with fluent and non-fluent aphasia are caused, at least partly, by breakdowns at different levels of language processing – lexical-semantic and morphosyntactic respectively. To test this, we performed a study in healthy and aphasic Russian individuals using the method of event-related potentials (ERPs) that has become a powerful tool in addressing temporal aspects of language processing.
51st Academy of Aphasia Proceedings
The distractive effects on attentional task performance in different paradigms are analyzed in this paper. I demonstrate how distractors may negatively affect (interference effect), positively (redundancy effect) or neutrally (null effect). Distractor effects described in literature are classified in accordance with their hypothetical source. The general rule of the theory is also introduced. It contains the formal prediction of the particular distractor effect, based on entropy and redundancy measures from the mathematical theory of communication (Shannon, 1948). Single- vs dual-process frameworks are considered for hypothetical mechanisms which underpin the distractor effects. Distractor profiles (DPs) are also introduced for the formalization and simple visualization of experimental data concerning the distractor effects. Typical shapes of DPs and their interpretations are discussed with examples from three frequently cited experiments. Finally, the paper introduces hierarchical hypothesis that states the level-fashion modulating interrelations between distractor effects of different classes.
The results of research of different areas of personality of homeless men: values, life attitudes, activity, homelessness area is presents. The data indicate the presence of a number of characteristics inherent in varying degrees all homeless people. The data obtained can be used to build an effective program of psychological re-socialization of homeless people.
The present article continues the investigation of the Soqotri verbal system undertaken by the Russian-Soqotri fieldwork team. The article focuses on the so-called “weak” and “geminated” roots in the basic stem. The investigation is based on the analysis of full paradigms (perfect, imperfect and jussive) of more than 170 “weak” and “geminated” Soqotri verbs.