Biomedical subjects

Beth A Ober

Publications and source records attributed to Beth A Ober.

5 recordsLinked to original sources

PubMed2003

Both processing speed and semantic memory organization predict verbal fluency in schizophrenia.

We systematically examined the relationship of both lexical retrieval and semantic memory organization to categorical verbal fluency performance in 40 outpatient schizophrenic subjects and 16 healthy controls. Mean choice reaction time (RT) on a lexical decision task was used as a measure of lexical retrieval efficiency. The complexity of semantic memory organization was measured using a Pathfinder semantic network analysis (calculated as the number of inter-node links obtained from a similarity rating task). In the schizophrenia group only, RT and semantic network links were each significantly negatively correlated with fluency and, together, accounted for 23% of the variance in fluency. RT and links were not significantly correlated with one another. Findings were unrelated to age, sex, education, or medication dose. Controlling for IQ reduced but did not abolish the relationship between fluency and network links. We conclude that the restricted verbal output of schizophrenic subjects is related both to impaired lexical retrieval and to variation in semantic memory organization, which partly reflects general intelligence. The statistical independence of the retrieval speed and organizational factors suggests that individuals with schizophrenia differ in the underlying processes that contribute to their reduced verbal fluency.

Adult↗

PubMed2003

New directions in the study of semantic deficits: a comment on Storms et al. (2003).

G. Storms, T. Dirikx, J. Saerens, S. Verstaeten, and P. P. De Deyn (2003) have provided an important critique of the use of multidimensional scaling (MDS) to evaluate semantic knowledge in Alzheimer's disease. If MDS is to be used with semantic proximity data (in spite of well-documented reasons for not doing so), at minimum, the issues raised in G. Storms et al. should be considered. A few criticisms of the target article are presented. Then, the manner in which key points from the article, along with a consideration of such factors affecting proximity elicitation as semantic domains, tasks, and the experimental context, could be applied to correct certain shortcomings in the literature are discussed.

Alzheimer Disease↗

PubMed2003

Slowed lexical access is uniquely associated with positive and disorganised symptoms in schizophrenia.

INTRODUCTION: This study addressed the relationship of both semantic priming and slowed lexical access to the symptoms of schizophrenia, and evaluated their association with other neurocognitive deficits. METHODS: 57 outpatients with schizophrenia and 20 nonpsychiatric control subjects performed a lexical decision semantic priming task (LDT), and a brief neuropsychological battery. The schizophrenia group was also assessed with an extended Positive and Negative Symptom Scale. RESULTS: As expected, the schizophrenia group had significantly slower reaction times (RTs) than the control group, and poorer performance on most neuropsychological tasks. Both groups exhibited semantic priming effects in both automatic and controlled processing conditions; these effects were not significantly different between groups. RT was unrelated to age, illness duration, GAF scores, or neuroleptic dose; controlled semantic priming effects were related to illness duration only. RT to real word targets (but not to nonwords) on the LDT was significantly correlated with positive and disorganised, but not negative symptoms. The neurocognitive correlates of RT slowing were: full-scale IQ and verbal fluency, but not attention; working memory; episodic memory retrieval; executive function, or manual speed. Both controlled semantic priming effects as well as the difference between controlled and automatic priming effects were related to executive functions in general. Severity of symptoms in the three major symptom groups was generally unassociated with impairment on the neuropsychological battery. The associations of RT slowing to positive and disorganised symptoms remained even after controlling for each of the above clinical and neurocognitive measures. CONCLUSIONS: These findings suggest that in schizophrenia, slowed lexical access is uniquely related to positive and disorganised symptoms. This relationship is not accounted for by more general cognitive deficits, overall illness severity, or generalised effects of symptoms on cognitive function. This relationship may reflect a specific impairment in the access to semantic memory.

Journal Article↗

PubMed2002

Semantic priming in schizophrenia: a review and synthesis.

In this paper, we present a review of semantic priming experiments in schizophrenia. Semantic priming paradigms show utility in assessing the role of deficits in semantic memory network access in the pathology of schizophrenia. The studies are placed in the context of current models of information processing. In this review we include all English-language reports (from peer-reviewed journals) of single-word semantic priming studies involving participants with schizophrenia. The studies to date show schizophrenic patients to exhibit variable semantic priming effects under automatic processing conditions, and consistent impairments under controlled/attentional conditions. We also describe associations with other neurocognitive dysfunction, neurochemical and electrophysiological disturbances, and clinical manifestations (such as thought disorder).

Clinical Trials as Topic↗

PubMed2002

RT and non-RT methodology for semantic priming research with Alzheimer's disease patients: a critical review.

This paper provides a critical review of RT and non-RT methodology for the conduct of research on semantic priming in Alzheimer's disease (AD) compared to elderly normal (EN) individuals. The review is organized by type of semantic priming (or attribute-knowledge) paradigm. Theoretical as well as methodological issues are highlighted insofar as they are relevant to: (1) the design, conduct, and analysis of semantic priming experiments (and closely related types of experiments) with AD compared to EN participants, and (2) the interpretation of findings from these experiments. Recommendations are provided for further research involving semantic priming and related paradigms with AD and certain other neuropsychological populations.

Aged↗