Browsing by Subject "subakuutti"

Background. Aphasia is a linguistic disorder that occurs after language acquisition and is most commonly caused by stroke. Research on novel word acquisition can contribute to the development of aphasia rehabilitation because it helps understand the relearning of words lost due to aphasia. Novel word acquisition has been researched mainly in chronic aphasia, in which learning is possible but shows large individual variation. There is initial evidence that novel word learning is also possible in non-chronic aphasia. Aims. The objective of this thesis is to study recovery and novel word learning in the subacute and chronic stages of aphasia. The thesis will also look into possible connections between learning in subacute aphasia and learning in chronic aphasia. These connections have not been previously explored. Methods. The multiple case study included four aphasic participants who were examined 0–3 months after stroke and again 12 months after stroke. The examination consisted of cognitive-linguistic background tests, questionnaires and a computer-based novel word learning task. In the latter, the participant was tasked with learning the associations between given pseudo-words and images through feedback and repetition. Research data was analyzed case by case. Results and conclusions. Recovery and novel word learning in subacute and chronic aphasia varied among the participants. In both stages, some participants learned new vocabulary and were able to transfer it into their long-term memory. The changes in novel word learning from subacute to chronic aphasia also varied among the subjects. These changes were not systematically connected with the severity of the participants’ aphasia, their baseline learning ability or an alleviation of cognitive-linguistic symptoms. Learning ability in subacute aphasia does therefore not always appear to predict learning ability in chronic aphasia, but novel word learning is possible in both subacute and chronic aphasia. Aphasia recovery shows considerable individual variation.

Background. Aphasia is a linguistic disorder most commonly caused by a stroke. The ability to learn is essential to rehabilitation from aphasia. Verbal short-term memory is seen as one prerequisite for verbal learning and refers to the temporary, limited-capacity storage of linguistic information. It might explain the individual variation in the learning ability of people with aphasia since studies have shown that verbal short-term memory impairments are common in aphasia but may not occur in all individuals. A correlation has also been found between verbal short-term memory and novel word learning ability in chronic aphasia but some of the research findings are contradictory. Verbal short-term memory is little studied in the subacute stage of aphasia. Also, the relationship between verbal short-term memory and novel word learning ability has not been previously studied in subacute aphasia. Aims. The aim of this study was to examine verbal short-term memory in subacute aphasia and compare it with verbal short-term memory in healthy controls. The objective was also to determine whether there is a relationship between verbal short-term memory and novel word learning ability in people with aphasia and healthy subjects. Methods. 10 aphasic individuals were examined 0–3 months post-stroke. The control group consisted of 20 healthy elderly subjects. Verbal short-term memory was measured with a word pointing span task in which participants heard sequences of words and pointed corresponding images in a visual array of items. Novel word learning ability was examined with a computer-based word learning task in which participants’ task was to learn to identify correct nonword-visual referent associations on the basis of online visual feedback. The data was analyzed with statistical methods, as well as at the individual level. Results and conclusions. At the group level, verbal short-term memory capacity of the aphasic subjects was lower than that of the healthy controls, but there was individual variation. Some of the aphasic subjects had impaired verbal short-term memory, some performed at the level of the controls and one subject presented only partially impaired verbal short-term memory, regarding the span for serial order. Both the healthy and the aphasic subjects recalled items better than simultaneously their order. Verbal short-term memory capacity correlated with the severity of aphasia, naming accuracy and language processing skills of the aphasic subjects. Verbal short-term memory was not correlated with novel word learning ability in the aphasic and healthy subjects. Consequently, verbal short-term memory does not predict novel word learning ability, and even weak verbal short-term memory does not impede learning. However, the results suggested some kind of link between verbal short-term memory and novel word learning ability.

Aphasia is a linguistic disorder that occurs after language acquisition and can lead to difficulties with expressive and receptive language. Aphasia is most often caused by a stroke. The inability to retrieve words, also known as anomia, is the most common symptom of aphasia and it is most often assessed with object-naming tasks. It is acknowledged that in aphasia learning is fundamental aspect of the recovery process and this has led to increasing interest to study novel word learning ability in aphasia. So far, word learning ability in people with aphasia has been studied mainly in chronic stage. The aim of this study was to examine novel word learning ability in subacute aphasia using recognition and naming task and to investigate the possible connection between recognition and naming ability. Additionally, the possible connection between naming of familiar objects and new objects was investigated. The sample of this study was part of the Opi sanoja research project and included ten adults with subacute aphasia (maximum 3 months post-stroke). Participants completed a learning task on computer and their aim was to learn six pseudoword-picture pairings. The novel word learning ability of the participants was assessed using recognition and confrontation naming task. The tasks were administered on two different occasions one week apart from each other. The ability to name familiar objects was assessed using Boston Naming Test. Participants’ ability to name novel objects wasn’t correlated with their ability to recognize the novel objects. Furthermore, participants’ ability to name familiar objects didn’t correlate with the ability to name novel objects. However, there was considerable inter-individual variability in learning performance. Some of the participants were able to recognize novel objects at the statistically significant level immediately after the learning task and one week later. However, some of the participant’s couldn’t recognize the objects either immediately after the learning task or one week later. At the group level participants’ performance on the novel object naming task was poor and was virtually at floor. However, consideration of individual participant results revealed that one of the participants was able to name some of the novel objects correctly. Based on the results, people in subacute aphasia recognize novel targets better than name them. The results are in line with previous studies that have investigated ability to learn new words in chronic aphasia and support the initial evidence that people with subacute aphasia can learn novel words. The findings of this study also provide preliminary understanding of the ability to name novel objects in subacute aphasia.

Background. One way to define aphasia is to consider it as an impairment of language functions emerging after the period of language acquisition. Aphasia is most often due to an ischemic or hemorrahagic stroke and causes common problems in word retrieval, naming as well as expressive and receptive language skills. The symptoms of aphasia may be mild moderate, severe or most severe depending on the lesion size and location. The recovery from aphasia is based on the reorganization of neural networks in the brain and is generally divided into three main phases: acute, subacute and chronic. Acquisition of novel words requires intensive exposition to them through hearing or seeing as well as a good functioning of short-term and long-term memories. There has been only a little research in acquisition of novel words in subacute aphasia. Objectives. The aim of this thesis is to investigate the ability of a person in subacute phase of aphasia to learn novel words in a situation resembling ambiguous natural language learning context. Another aim is to study the connection between the learning ability and the language profile of the participant. Methods. The research material consisted of background information of the participant as well as the results of linguistic-cognitive tests and the novel word learning test. In the last-mentioned the participant learned six nonwords and their picture referents cross-situationally which means that the correct word-referent pairs develop gradually with the help of participant's own observations and feedback. Results and conclusions. Compared to the results of the nearest study available as to the study design the participant showed both statistically significant ability to learn novel words and also ability to store the new material during one week after the testing. In spite of a severe aphasia the participant reached the highest learning results together a chronic participant whose aphasia severity grade was mild. One possible explanation to this may be that the participant could make a successful advantage of both the residual of the linguistic-cognitive profile as well as the visual modality of the word learning task.

Background. Aphasia refers to a disability in the processing of linguistic information. It is most typically due to a stroke. Aphasia impairs a person's ability to understand, produce and use language. Recovery from aphasia is generally divided into three main stages: acute, subacute and chronic. So far, the ability to learn new words in aphasia has only been studied in chronic aphasia. Learning new words is a complex process. In natural language learning, the relationship between a word and its meaning is often not unambiguous, but the words and their possible meanings are numerous, and the connections are complex. The learning of new words can take place by hearing or by reading. The prerequisite for rehabilitation from aphasia is the ability to learn new things, but aphasia research typically uses familiar and everyday words. However, the use of familiar words in research makes it difficult to interpret the results. In order to assess whether a person with aphasia is able to learn new vocabulary, research must be done on a vocabulary that was not available to the person before aphasia. Objectives. The aim of this thesis is to determine, whether people with subacute aphasia can learn novel vocabulary in a situation that imitates natural language learning. This thesis also investigates how the learning ability of people with aphasia compares to the learning ability of healthy matched controls in the same task and how the matched controls learn compared to healthy young adults. Methods. The participants of the study consisted of three groups: young controls, matched controls and aphasic participants. The aphasic participants were examined at HUS Hospital District in Laakso Hospital in Helsinki and in Hyvinkää Hospital. The word learning task consisted of six 3-syllable nonwords that were practiced using a computer program. The task was to combine a spoken and written novel word with the correct novel image, choosing from two different images. Results and conclusions. Learning novel words is possible in subacute aphasia. However, there was great variability in the ability to learn between the aphasic participants. Some learned the words well, others learned some words, and some did not seem to learn the words at all. In addition, some of aphasic participants in the subacute stage were able to maintain the vocabulary they learned for at least a week after learning. Some of the aphasic participants learned the words on par with matched controls but for some the learning was significantly weaker. Both young adults and matched controls performed well on the learning task, but young adults learn the words faster than matched controls.