Biomedical subjects

Tamiko Azuma

Publications and source records attributed to Tamiko Azuma.

7 recordsLinked to original sources

PubMed2004

Working memory and perseveration in verbal fluency.

Letter and semantic fluency tasks are often used in neuropsychological assessment and are sensitive to many conditions. Performance is assessed by correct responses and errors, including perseverations. Healthy young adults performed letter and semantic fluency tasks. One group performed these tasks in the conventional manner; 2 other groups performed them while maintaining memory loads. The memory loads consisted either of words from the same category as the fluency task or of words from a different category. The results showed little effect of memory loads on correct responses but significant effects of memory load on perseveration rates: Same-category loads resulted in higher rates, especially in letter fluency. The results are discussed in terms of frontal lobe function in verbal fluency.

Analysis of Variance↗

PubMed2004

Sensitivity to expectancy violations in healthy aging and mild cognitive impairment.

In this study, individuals with mild cognitive impairment (MCI) were tested to see if executive dysfunction impacts their implementation of expectancy biases in a priming task. Young adults, healthy older adults, and individuals with MCI made speed-related decisions to sequentially presented word pairs. The proportion of category related (e.g., apple-fruit) versus coordinate related (apple-pear) pairs was varied to create different expectancy biases. When the proportion of category pairs was high (80%), the control groups showed an expectancy bias: Significant inhibition was observed for coordinate pairs compared with category pairs. The MCI group also demonstrated an expectancy bias but with much larger costs for unexpected targets. The findings suggest that individuals with MCI are inordinately sensitive to expectancy violations, and these findings are discussed in terms of possible executive dysfunction.

Adolescent↗

PubMed2004

Episodic memory reflected in printed word naming.

Although memory is typically measured by recall or recognition, it is also expressed by fluent or stylized task performance. In this experiment, 12 volunteers (called speakers) completed four experimental stages over a 2-week period. They read printed words aloud in two sessions, before and after exposure to auditory training tokens. They later completed a recognition memory test, discriminating old from new words. Groups of perceptual judges assessed the speakers' vocal imitation by comparing utterances recorded before and after training and deciding which sounded like "better imitations" of the training tokens. The data showed clear evidence of postexposure imitation, with systematic effects that preclude strategic explanations. The contents of episodic memory were reflected by participants' speaking style while they were reading aloud. Together, the imitation and recognition data suggest that memory preserves detailed traces of spoken words; those traces were apparently activated when participants later read the same words in the same context.

Humans↗

PubMed2004

Paws + cause = pause? Memory load and memory blends in homophone recognition.

Previous research has shown that separate information sources, activated closely together in time, can induce errors suggestive of memory blends. In Experiment 1, homophones were used to induce such memory errors. In a study task, participants made relatedness judgments to word pairs that included homophones (e.g., PAWS-BEAR). During this task, one group (study-similar) maintained memory loads with words that were orthographically similar to the presented homophones (e.g., JAWS). Another group (test-similar) maintained memory loads similar to those obtained for the study homophone's alternate spelling (e.g., CAUSE). A third group maintained no memory load during the task. In a surprise recognition test, participants were presented both previously viewed homophones (PAWS) and non-presented alternate spellings (PAUSE). We hypothesized that partially activated alternate spellings, in conjunction with the orthographically similar memory words, would result in the creation of blended memories. The results followed suit: The test-similar condition produced significantly elevated false alarms, relative to both the study-similar and the no-load conditions. Experiment 2 replicated these results while including memory loads to control for potential orthographic confusions. The findings are discussed in terms of multiple, episodic memories later activated as single, blended memories.

Humans↗

PubMed2003

A longitudinal study of neuropsychological change in individuals with Parkinson's disease.

Neuropsychological changes in individuals with Parkinson's disease (PD) were studied longitudinally. Sixty-nine idiopathic PD patients, with Mini-Mental State Examination (MMSE) scores falling within normal range, and 37 elderly control participants were given neuropsychological tests twice approximately two years apart. The PD group performed poorer than the control group on Semantic Fluency, Letter Fluency, Modified Wisconsin Card Sorting Task, and Block Design at test time 1. Two years later, the PD group showed significant decline in Semantic and Letter Fluency. A subset of 12 PD patients declined in mental status by second testing (> or =4 MMSE points). Cox proportional-hazards models were used to see if any baseline measures were associated with relative risk of decline in mental status. In the final model, Repetition performance and Age were significantly associated with cognitive decline. Consistent with previous studies, executive function tasks were those most susceptible to disease progression.

Aged↗

PubMed2003

A longitudinal study of neuropsychological change in individuals with Parkinson's disease.

OBJECTIVES: Neuropsychological changes in individuals with Parkinson's disease (PD) were studied longitudinally. METHODS: Sixty-nine idiopathic PD patients, with Mini-Mental State Examination (MMSE) scores falling within normal range, and 37 elderly control participants were given neuropsychological tests twice approximately two years apart. RESULTS: The PD group performed poorer than the control group on Semantic Fluency, Letter Fluency, Modified Wisconsin Card Sorting Task, and Block Design at test time 1. Two years later, the PD group showed significant decline in Semantic and Letter Fluency. A subset of 12 PD patients declined in mental status by second testing (>4 MMSE points). Cox proportional-hazards models were used to see if any baseline measures were associated with relative risk of decline in mental status. In the final model, Repetition performance and Age were significantly associated with cognitive decline. CONCLUSIONS: Consistent with previous studies, executive function tasks were those most susceptible to disease progression.

Aged↗

PubMed2003

"Blaming the victim" under memory load.

When presented with negative outcomes, people often engage in counterfactual thinking imagining various ways that events might have been different. This appears to be a spontaneous behavior, with considerable adaptive value. Nevertheless, counterfactual thinking may also engender systematic biases in various judgment tasks, such as allocating blame for a mishap, or deciding on the appropriate compensation to a victim. Thus, counterfactuals sometimes require thought suppression or discounting, potentially resource-demanding tasks. In this study. participants made mock-jury decisions about control and counterfactual versions of simple stories. The judgments of two groups of participants, differing in their respective levels of working memory capacity, were compared. In addition, all participants held memory loads during various stages of the primary task. Lower-span individuals were especially susceptible to bias associated with the counterfactual manipulation, but only when holding memory loads during judgment. The results suggest that counterfactual thoughts arise automatically, and may later require effortful, capacity-demanding suppression.

Crime Victims↗