What memory does language need: study of the impact of memory types and components on language in healthy individuals and in patients with local brain pathology

The main aim of the current project was  to investigate types and components of memory, their role in language processes, and the specificity of the psychological organization of these two higher cortical functions in healthy controls and individuals with focal brain lesions.  To resolve this problem the study employed contemporary multidisciplinary methodology and was based on theoretical foundations of cognitive psychology and neuropsychology, computerized experimental methods of psychology and neurolinguistics, eye-tracking methods and neuropsychological assessment, and morphological analysis of brain scans. For the empirical part of the research project, new tasks for assessment of memory and its submechanisms were developed, some of them employing eye tracking.  In the current study eye-tracking tasks to index working memory capacity were employed for the first time in Russian. These type of eye tracking tasks look particularly promising for aphasia research as concomitant speech and motor impairments may be a confound in the assessment of working memory using traditional tasks. During the main phase of the project data of 40 healthy Russian speakers and 41 persons with aphasia were collected.  Participants with aphasia included 20 individuals with nonfluent aphasia, and 21 – fluent. The inclusion of these two groups of participants allowed to investigate the specificity of cognitive impairments in aphasia and their interaction with other linguistic processes.

In the current project we demonstrated a significant correlation between verbal and nonverbal memory tasks, supporting the notion of domain-general working memory capacity.  Then our data demonstrated a differential impact of speed of processing and sustained attention on working memory capacity in healthy controls; this pattern was not observed in individuals with aphasia.  Next, our data showed that both memory and attentional resources were significantly decreased in individuals with aphasia.  Notably, these deficits were observed even in individuals with mild language impairments. Next, the simultaneous influence of different cognitive mechanisms (memory, attention, speed of processing) on auditory language comprehension in individuals with fluent and non-fluent aphasia was investigated.  For individuals with non-fluent aphasia working memory span, sustained attention, efficiency of attention switching, and speed of processing each made a unique and a significant contribution to language comprehension.  While for fluent aphasia only speed of processing had an impact. Our results are compatible with numerous non-linguistic interpretations of non-fluent (agrammatic) aphasia, where overall sluggishness and decreased the rate of information processing, along with reduced processing capacity are postulated to play a pivotal role in the observed language deficits. While in fluent aphasia a lexical-semantic deficit is considered to be of central importance with concomitant cognitive deficits having only a secondary role. Our results have implications for clinical practice and design of therapy protocols. For aphasia assessment, it is important to evaluate cognitive functions besides language, especially in patients with non-fluent aphasia, and further target these cognitive impairments in treatment.

Publications

Ivanova, M.V.,  Kuptsova S.V., Dragoy, O.V., Ulicheva, A.S., Laurinavichyute, A.K., & Petrova, L.V. (2013). What cognitive mechanisms impact language comprehension in aphasia?  Procedia – Social and Behavioral Sciences 94, 101-102
Иванова М.В., Купцова С.В., Драгой О.В., Лауринавичюте А.К., Уличева А.С., Петрова Л.В., Какие когнитивные процессы
влияют на понимание речи при афазии., Когнитивная наука в Москве: новые исследования. Тезисы конференции (19 июня 2013 г.). Науч. ред.: Е. В. Печенкова, М. В. Фаликман., Букиведи, Москва, 2013, 131 - 135
Ivanova, M.V., Dragoy, O.V., Kuptsova S.V., Ulicheva, A.S., Laurinavichyute, A.K., & Petrova, L.V., Lexical processing and working memory in individuals with and without aphasia, CUNY2013, 26th Annual CUNY Conference on Human Sentence Processing, 2013, 2013, 270 - 270
Купцова С.В., Иванова М.В., Драгой О.В., Петрова Л.В., Пономарева А.А., Уличева А.С., Лауринавичюте А.К., Особенности нарушения
концентрации внимания у больных с разными формами афазии., Психологические исследования, 2013

The project is supported by RFH grant №12-06-00939а (2012 - 2013), principal investigator - Maria Ivanova