Long-term maintenance of novel vocabulary in persons with chronic aphasia

Abstract

Background:The study of novel word learning in aphasia can shed light on the functionality of patients' learning mechanisms and potentially help in treatment planning. Previous studies have indicated that persons with aphasia are able to learn some new vocabulary. However, these learning outcomes appear short-lived and evidence for the ability to use the newly learned words in the long term is lacking. Aims: Participants with aphasia and matched controls underwent short training where they were taught to name novel objects with novel names. We studied the participants' word learning and particularly their long-term maintenance. We also examined whether the language and verbal short-term memory impairments of the participants with aphasia related to their ability to acquire and maintain phonological and semantic information on novel words. Methods & Procedures: Two participants with nonfluent aphasia, LL and AR, and two matched controls took part in the experiment. They were taught to name 20 unfamiliar objects by repeating the names in the presence of the object picture. Half of the items carried a definition that was used to probe incidental semantic learning. There were four training sessions, a post-training test, and follow-up tests up to 6 months post-training. Learning measures included recognition of the trained objects, as well as spontaneous and cued recall in visual confrontation naming. Incidental semantic learning was measured by spontaneous recall of the definitions. Outcomes & Results: Combining spontaneous and phonologically cued responses, LL acquired 70% and AR 55% of the novel words. With phonological cueing, LL named 50% of the items correctly up to 6 months post-training (vs 95-100% for the controls)

Factors influencing treatment-induced language recovery in chronic, post-stroke aphasia

“…An emerging body of research has employed the use of novel word learning to investigate verbal learning in adults with aphasia (Gupta et al, 2006;Tuomiranta et al, 2011;Tuomiranta et al, 2012). The use of unfamiliar pictures (i.e., novel semantics) paired with novel word forms in a novel word learning task is suggested to provide a relatively pure measure of individuals' verbal learning capacity.…”

“…A number of studies have explicitly evaluated verbal and non-verbal learning ability in adults with chronic aphasia (Gupta, Martin, Abbs, Schwart, & Lipinski, 2006;Kelly & Armstrong, 2009;Tuomiranta et al, 2011;Tuomiranta, Rautakoski, Rinne, Martin, & Laine, 2012;Vallila-Rohter & Kiran, 2013a, 2013b) and a detailed review of this research is provided in Chapter Five. This research has demonstrated that whilst individuals with aphasia are able to learn new information, both verbal and non-verbal learning mechanisms are impaired in adults with aphasia (Gupta et al, 2006;Kelly & Armstrong, 2009;Vallila-Rohter & Kiran, 2013a).…”

“…Preliminary research indicates that the learning trajectory in individuals with aphasia is different to healthy adults (Vallila-Rohter & Kiran, 2013a). Whilst there is evidence that individuals with aphasia are able to acquire new information, it is suggested that both verbal and non-verbal learning processes may be impaired in individuals with aphasia (Tuomiranta et al, 2012;Vallila-Rohter & Kiran, 2013a, 2013b.…”

“…A small number of studies have investigated novel word learning in individuals with aphasia (Breitenstein et al, 2004;Freedman & Martin, 2001;Gupta et al, 2006;Kelly & Armstrong, 2009;Tuomiranta et al, 2011;Tuomiranta et al, 2012). These studies indicate that people with aphasia retain, at least in some capacity, the ability to acquire novel verbal information.…”

“…The use of previously acquired, familiar stimuli (i.e., known word forms and/or meanings) combined with a novel word form or meaning allows individuals' to rely on existing representations to support their learning. Furthermore, the use of familiar stimuli may be influenced by factors such as imageability, word frequency and word-priming effects (Tuomiranta et al, 2012). Alternatively, the use of entirely novel stimuli (e.g., novel word form paired with novel semantics) enables a relatively pure investigation of individuals' word learning abilities.…”