Browsing by Subject "Verbal fluency"

Now showing 1 - 4 of 4
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    A comparison of techniques for deriving clustering and switching scores from verbal fluency word lists
    (Frontiers Media, 2022-09-14) Bushnell, Justin; Svaldi, Diana; Ayers, Matthew R.; Gao, Sujuan; Unverzagt, Frederick; Del Gaizo, John; Wadley, Virginia G.; Kennedy, Richard; Goñi, Joaquín; Clark, David Glenn; Neurology, School of Medicine
    Objective: To compare techniques for computing clustering and switching scores in terms of agreement, correlation, and empirical value as predictors of incident cognitive impairment (ICI). Methods: We transcribed animal and letter F fluency recordings on 640 cases of ICI and matched controls from a national epidemiological study, amending each transcription with word timings. We then calculated clustering and switching scores, as well as scores indexing speed of responses, using techniques described in the literature. We evaluated agreement among the techniques with Cohen's κ and calculated correlations among the scores. After fitting a base model with raw scores, repetitions, and intrusions, we fit a series of Bayesian logistic regression models adding either clustering and switching scores or speed scores, comparing the models in terms of several metrics. We partitioned the ICI cases into acute and progressive cases and repeated the regression analysis for each group. Results: For animal fluency, we found that models with speed scores derived using the slope difference algorithm achieved the best values of the Watanabe-Akaike Information Criterion (WAIC), but with good net reclassification improvement (NRI) only for the progressive group (8.2%). For letter fluency, different models excelled for prediction of acute and progressive cases. For acute cases, NRI was best for speed scores derived from a network model (3.4%), while for progressive cases, the best model used clustering and switching scores derived from the same network model (5.1%). Combining variables from the best animal and letter F models led to marginal improvements in model fit and NRI only for the all-cases and acute-cases analyses. Conclusion: Speed scores improve a base model for predicting progressive cognitive impairment from animal fluency. Letter fluency scores may provide complementary information.
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    Neural evidence of switch processes during semantic and phonetic foraging in human memory
    (National Academy of Science, 2023) Lundin, Nancy B.; Brown, Joshua W.; Johns, Brendan T.; Jones, Michael N.; Purcell, John R.; Hetrick, William P.; O’Donnell, Brian F.; Todd, Peter M.; Psychiatry, School of Medicine
    Humans may retrieve words from memory by exploring and exploiting in "semantic space" similar to how nonhuman animals forage for resources in physical space. This has been studied using the verbal fluency test (VFT), in which participants generate words belonging to a semantic or phonetic category in a limited time. People produce bursts of related items during VFT, referred to as "clustering" and "switching." The strategic foraging model posits that cognitive search behavior is guided by a monitoring process which detects relevant declines in performance and then triggers the searcher to seek a new patch or cluster in memory after the current patch has been depleted. An alternative body of research proposes that this behavior can be explained by an undirected rather than strategic search process, such as random walks with or without random jumps to new parts of semantic space. This study contributes to this theoretical debate by testing for neural evidence of strategically timed switches during memory search. Thirty participants performed category and letter VFT during functional MRI. Responses were classified as cluster or switch events based on computational metrics of similarity and participant evaluations. Results showed greater hippocampal and posterior cerebellar activation during switching than clustering, even while controlling for interresponse times and linguistic distance. Furthermore, these regions exhibited ramping activity which increased during within-patch search leading up to switches. Findings support the strategic foraging model, clarifying how neural switch processes may guide memory search in a manner akin to foraging in patchy spatial environments.
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    Verbal Fluency in a National Sample: Telephone Administration Methods
    (Wiley, 2019-01-18) Marceaux, Janice C.; Prosje, Michelle A.; McClure, Leslie A.; Kana, Bhumika; Crowe, Michael; Kissela, Brett; Manly, Jennifer; Howard, George; Tam, Joyce W.; Unverzagt, Frederick W.; Wadley, Virginia G.; Psychiatry, School of Medicine
    Objectives: Describe novel methods for ascertaining verbal fluency in a large national sample of adults, examine demographic factors influencing performance, and compare scores to studies using in-person assessment. Methods/Design: Participants were from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national, population-based, longitudinal study of stroke in adults aged 45 years an older. Letter and semantic fluency were gathered, using Letter “F” and Animal Naming, via a telephone-based assessment with computer-assisted scoring of digital recordings. Results: Initial letter and semantic fluency scores were obtained on 18,505 and 18,072 participants, respectively. For both fluency tests, scores were normally distributed. Younger age and more years of education were associated with better performances (p<0.0001). The mean and standard deviation for matched subgroups, based on age, gender, and education, were quite comparable to scores reported out of samples using an in-person administration format. Telephone-based assessment also allowed for a level of quality control not available via in-person measurement. Conclusions: Telephone-based assessment of verbal fluency and computer-assisted scoring programs designed for this study facilitated large scale data acquisition, storage, and scoring of protocols. The resulting scores have similar characteristics to those obtained by traditional methods. These findings extend validation of cognitive assessment methods, using survey research staff and computer-assisted technology for test administration.
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    Verbal fluency response times predict incident cognitive impairment
    (Alzheimer’s Association, 2022-04-06) Ayers, Matthew R.; Bushnell, Justin; Gao, Sujuan; Unverzagt, Frederick; Del Gaizo, John; Wadley, Virginia G.; Kennedy, Richard; Clark, David Glenn; Neurology, School of Medicine
    Introduction: In recent decades, researchers have defined novel methods for scoring verbal fluency tasks. In this work, we evaluate novel scores based on speed of word responses. Methods: We transcribed verbal fluency recordings from 641 cases of incident cognitive impairment (ICI) and matched controls, all participants in a large national epidemiological study. Timing measurements of utterances were used to calculate a speed score for each recording. Traditional raw and speed scores were entered into Cox proportional hazards (CPH) regression models predicting time to ICI. Results: Concordance of the CPH model with speed scores was 0.599, an improvement of 3.4% over a model with only raw scores and demographics. Scores with significant effects included animals raw and speed scores, and letter F speed score. Discussion: Novel verbal fluency scores based on response times could enable use of remotely administered fluency tasks for early detection of cognitive decline. Highlights: The current work evaluates prognostication with verbal fluency speed scores. These speed scores improve survival models predicting cognitive decline. Cases with progressive decline have some characteristics suggestive of Alzheimer's disease. The subset of acute decliners is probably pathologically heterogeneous.