scholarly journals A Cognitive Psychometric Investigation of Word Production and Phonological Error Rates in Logopenic Progressive Aphasia

2021 ◽  
pp. 1-9
Author(s):  
Diana Petroi ◽  
Grant M. Walker ◽  
Joseph R. Duffy ◽  
Gregory S. Hickok ◽  
Keith A. Josephs
Keyword(s):  
Error Rates ◽  
Word Production ◽  
Task Demands ◽  
Least Squares Regression ◽  
Progressive Aphasia ◽  
Fit Statistics ◽  
Psychometric Models ◽  
Suppression Tendency ◽  
Phonological Errors ◽  
Psychometric Investigation

Purpose This study investigated the relationship between word production rates (WPRs) and phonological error rates (PERs) in generative and responsive tasks in logopenic progressive aphasia (lvPPA). We examined whether a portion of the reduced WPR during generative tasks related directly to phonological impairments affecting PER on all tasks, irrespective of other task differences that contributed to WPR. Method Two cognitive psychometric models were hypothesized and fit to the total number of words produced and the number of phonological errors produced by 22 participants on 10 tasks. Bayesian inference was used to construct posterior distributions of participant ability and task difficulty parameters. Model fit statistics were compared. Association strengths for average generative WPR and average responsive PER were also evaluated with linear least-squares regression. Results Average generative WPR and average responsive PER were significantly associated ( r = −.77, p = .00002). A cognitive psychometric model that assumed reduced WPR on generative tasks reflects a portion of general phonological impairment yielded better fit than a model that ignored performance differences between generative and responsive tasks. Generative fluency tasks that elicited few phonological errors still reflected phonological impairment, via suppression. Individual participants were estimated to suppress between 62% and 93% of phonological errors on generative tasks that would have emerged on responsive tasks. Conclusions Suppression of phonological errors may present as decreased WPR on generative tasks in lvPPA. Failure to account for this suppression tendency may lead to overestimation of phonological ability. The findings indicate the need to account for task demands in assessing lvPPA.

Single Word Production in Nonfluent Progressive Aphasia

1998 ◽  
Vol 61 (2) ◽  
pp. 226-273 ◽  
Author(s):  
Karen Croot ◽  
Karalyn Patterson ◽  
John R. Hodges
Keyword(s):  
Word Production ◽  
Single Word ◽  
Progressive Aphasia

scholarly journals A comparison between traditional ordinary least-squares regression and three methods for enforcing additivity in biomass equations using a sample of Pinus radiata trees

2020 ◽  
Vol 50 ◽  
Author(s):  
Mohan KC ◽  
Euan G. Mason ◽  
Horacio E. Bown ◽  
Grace Jones
Keyword(s):  
Least Squares ◽  
Pinus Radiata ◽  
Goodness Of Fit ◽  
Ordinary Least Squares ◽  
Total Biomass ◽  
Least Squares Regression ◽  
Above Ground Biomass ◽  
Fit Statistics ◽  
Biomass Equations ◽  
Power Transformations

Background: Additivity has long been recognised as a desirable property of systems of equations to predict the biomass of components and the whole tree. However, most tree biomass studies report biomass equations fitted using traditional ordinary least-squares regression. Therefore, we aimed to develop models to estimate components, subtotals and above-ground total biomass for a Pinus radiata D.Don biomass dataset using traditional linear and nonlinear ordinary leastsquares regressions, and to contrast these equations with the additive procedures of biomass estimation.Methods: A total of 24 ten-year-old trees were felled to assess above-ground biomass. Two broad procedures were implemented for biomass modelling: (a) independent; and (b) additive. For the independent procedure, traditional linear models (LINOLS) with scaled power transformations and y-intercepts and nonlinear power models (NLINOLS) without y-intercepts were compared. The best linear (transformed) models from the independent procedure were further tested in three different additive structures (LINADD1, LINADD2, and LINADD3). All models were evaluated using goodness-of-fit statistics, standard errors of estimates, and residual plots.Results: The LINOLS with scaled power transformations and y-intercepts performed better for all components, subtotals and total above-ground biomass in contrast to NLINOLS that lacked y-intercepts. The additive model (LINADD3) in a joint generalised linear least-squares regression, also called seemingly unrelated regression (SUR), provided the best goodness-of-fit statistics and residual plots for four out of six components (stem, branch, new foliage and old foliage), two out of three subtotals (foliage and crown), and above-ground total biomass compared to other methods. However, bark, cone and bole biomass were better predicted by the LINOLS method.Conclusions: SUR was the best method to predict biomass for the 24-tree dataset because it provided the best goodness-of-fit statistics with unbiased estimates for 7 out of 10 biomass components. This study may assist silviculturists and forest managers to overcome one of the main problems when using biomass equations fitted independently for each tree component, which is that the sum of the biomasses of the predicted tree components does not necessarily add to the total biomass, as the additive biomass models do.

scholarly journals On the Conditional and Unconditional Type I Error Rates and Power of Tests in Linear Models with Heteroscedastic Errors

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
Patrick J. Rosopa ◽  
Alice M. Brawley ◽  
Theresa P. Atkinson ◽  
Stephen A. Robertson
Keyword(s):  
Linear Models ◽  
Type I Error ◽  
Weighted Least Squares ◽  
Error Rates ◽  
Type I ◽  
Least Squares Regression ◽  
Type I Error Rates ◽  
Power Of Tests ◽  
Wide Range ◽  
Heteroscedastic Errors

Preliminary tests for homoscedasticity may be unnecessary in general linear models. Based on Monte Carlo simulations, results suggest that when testing for differences between independent slopes, the unconditional use of weighted least squares regression and HC4 regression performed the best across a wide range of conditions.

scholarly journals Antimicrobial susceptibility of flavobacteria as determined by agar dilution and disk diffusion methods.

1997 ◽  
Vol 41 (6) ◽  
pp. 1301-1306 ◽  
Author(s):  
J C Chang ◽  
P R Hsueh ◽  
J J Wu ◽  
S W Ho ◽  
W C Hsieh ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Regression Line ◽  
Error Rates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Poor Correlation ◽  
Least Squares Regression ◽  
Disk Diffusion Method ◽  
Agar Dilution

A total of 106 clinical isolates of flavobacteria, including 41 isolates of Flavobacterium meningosepticum, 59 of Flavobacterium indologenes, and 6 of Flavobacterium odoratum were collected from January 1992 to December 1995 from patients in Taiwan. The in vitro activities of antimicrobial agents were determined concomitantly by the standard agar dilution and disk diffusion methods. More than 90% of the flavobacterial isolates were resistant to cephalothin, cefotaxime, ceftriaxone, moxalactam, aztreonam, imipenem, aminoglycosides, erythromycin, and glycopeptides. The majority of F. meningosepticum isolates were susceptible to piperacillin and to minocycline but resistant to ceftazidime, with MICs at which 90% of the isolates are inhibited being 8, 4, and > 128 microg/ml, respectively. Approximately half of the F. indologenes isolates were susceptible to piperacillin, cefoperazone, ceftazidime, and minocycline, with MICs at which 50% of the isolates are inhibited being 4, 16, 8, and 4 microg/ml, respectively. The majority of F. odoratum isolates were resistant to all the antimicrobial agents tested except minocycline, to which five of six isolates were susceptible. With least-squares regression analysis and error rate-bounded analysis methods, the following resistant and susceptible zone diameter breakpoints were established: < or = 12 and > or = 17 mm, respectively, for piperacillin against F. meningosepticum and F. indologenes; < or = 13 and > or = 18 mm, respectively, for ceftazidime against F. meningosepticum and F. indologenes, < or = 17 and > or = 21 mm, respectively, for ofloxacin against F. indologenes; < or = 16 and > or = 20 mm, respectively, for ciprofloxacin against F. meningosepticum. Valid breakpoints for the disk diffusion method could not be established for cefoperazone and ofloxacin against F. meningosepticum and for minocycline against F. meningosepticum and F. indologenes due to a poor correlation coefficient for the regression line or for cefoperazone and ciprofloxacin against F. indologenes due to the presence of remarkable error rates.

scholarly journals Internal consistency and test-retest reliability of an affective task-switching paradigm

2020 ◽  
Author(s):  
Cindy Eckart ◽  
Dominik Kraft ◽  
Christian Fiebach
Keyword(s):  
Individual Differences ◽  
Response Time ◽  
Internal Consistency ◽  
Task Switching ◽  
Error Rates ◽  
Task Demands ◽  
Strong Response ◽  
Retest Reliability ◽  
Switch Costs ◽  
Test Retest Reliability

Affective flexibility refers to the flexible adaptation of behavior or thought given emotionally relevant stimuli, tasks, or contexts. Individual differences in affective flexibility have received increased interest in the past years, as they may relate to differences in the efficiency of emotion regulation and dealing with stress and adversity. One way to assess individual differences in affective flexibility is to assess the behavioral costs (in terms of increased response times or errors rates) of switching between affective and neutral tasks. However, behavioral task measures like switch costs can only be treated as trait-like individual difference characteristics if their psychometric quality has been established. To this end, we developed an affective task switching paradigm and report an analysis of the test-retest reliability (inter-session interval two weeks) as well as internal consistencies of affective switch costs. Our results show strong response time switch costs, both for switching from the neutral to the emotion task and vice versa, excellent internal consistency estimates for both measures from both sessions (Spearman-Brown corrected r = .92), and good test-retest reliabilities (ICC(2,1) of .78 and .82, respectively). Effect sizes and reliability estimates were substantially lower for switch costs calculated from error rates, which is consistent with previous literature discussing the psychometric properties of task-based cognitive measures. In conclusion, our results indicate that response time-based switch costs are well-suited as a measure of individual differences in the efficiency of affective flexibility, i.e., of dynamically adjusting behavior and thought in the context of emotional task demands.

Flanker-Task in Children

2009 ◽  
Vol 23 (4) ◽  
pp. 183-190 ◽  
Author(s):  
Björn Albrecht ◽  
Hartmut Heinrich ◽  
Daniel Brandeis ◽  
Henrik Uebel ◽  
Juliana Yordanova ◽  
...  
Keyword(s):  
Performance Monitoring ◽  
Flanker Task ◽  
Reaction Times ◽  
Event Related Potentials ◽  
Error Rates ◽  
Task Demands ◽  
Button Press ◽  
Multiple Systems ◽  
Time Frequency ◽  
Related Potentials

Response processing may comprise multiple systems working in parallel at different functional levels of performance monitoring. In time-frequency decompositions of response-locked event-related potentials from adults, a subprocess operating in the delta frequency band was interpreted as an index of cognitive error monitoring, distinguishable from a process with theta frequency probably related to motor control. However, it remains unclear whether such subprocesses can also be distinguished in children. In the current study, error processing was assessed in 22 normal boys aged 8 to 15 years using an Erikson Flanker task. Performance data revealed the expected indices of conflicting task demands, such as increased reaction times and error rates. A clear error-negativity was found in the response-locked event-related potentials after incompatible stimuli, and correct responses show a slow negative deflection immediately preceding the button-press, which is absent in errors. Time-frequency decompositions disclosed that a subprocess in the lower delta band preceding correct responses may reflect a more general action monitoring process sensitive to conflicting task demands that, moreover, may prevent one from making an error if it is active early enough. Processes in the delta and theta bands are modulated specifically by errors and may index motor-related monitoring in children. Moreover, these processes occurred considerably earlier for correct responses compared to errors, suggesting that their timing reflects some performance capacity. These considerations may help to clarify response processing in tasks with conflicting demands.

Word Production and Related Processes

2018 ◽  
pp. 505-526
Author(s):  
Myrna F. Schwartz
Keyword(s):  
Lexical Access ◽  
Incremental Learning ◽  
Adaptive Change ◽  
Word Production ◽  
Self Monitoring ◽  
Empirical Justification ◽  
Learning Hypothesis ◽  
Robust System ◽  
Phonological Errors

Clinicians have long appreciated that people with aphasia (PWA) who self-monitor their errorful speech have better outcomes. It has been assumed, with empirical justification, that this is because successful monitoring is associated with a stronger language system, and a robust system is more likely to improve (Strength hypothesis). A second possibility, not incompatible with the first, is that monitoring success in some way causes those language systems to undergo adaptive change (Learning hypothesis). This chapter describes recent evidence from PWA’s self-monitoring of naming errors that supports both the strength and learning hypotheses. A follow-up analysis of monitoring latencies speaks to differences in repair processes for semantic and phonological errors. The discussion develops an explanatory framework that integrates aspects of monitoring theory with models of lexical access and incremental learning.

scholarly journals CUSUM-Based Person-Fit Statistics for Adaptive Testing

2001 ◽  
Vol 26 (2) ◽  
pp. 199-217 ◽  
Author(s):  
Edith M.L.A. van Krimpen-Stoop ◽  
Rob R. Meijer
Keyword(s):  
Type I Error ◽  
Latent Trait ◽  
Theory Model ◽  
Error Rates ◽  
Type I ◽  
Person Fit ◽  
Detection Rates ◽  
Empirical Distributions ◽  
Fit Statistics ◽  
Item Scores

Item scores that do not fit an assumed item response theory model may cause the latent trait value to be inaccurately estimated. Several person-fit statistics for detecting nonfitting score patterns for paper-and-pencil tests have been proposed. In the context of computerized adaptive tests (CAT), the use of person-fit analysis has hardly been explored. Because it has been shown that the distribution of existing person-fit statistics is not applicable in a CAT, in this study new person-fit statistics are proposed and critical values for these statistics are derived from existing statistical theory. Statistics are proposed that are sensitive to runs of correct or incorrect item scores and are based on all items administered in a CAT or based on subsets of items, using observed and expected item scores and using cumulative sum (CUSUM) procedures. The theoretical and empirical distributions of the statistics are compared and detection rates are investigated. Results showed that the nominal and empirical Type I error rates were comparable for CUSUM procedures when the number of items in each subset and the number of measurement points were not too small. Detection rates of CUSUM procedures were superior to other fit statis­tics. Applications of the statistics are discussed.

Nonfluent progressive aphasia and semantic dementia: A comparative neuropsychological study

1996 ◽  
Vol 2 (6) ◽  
pp. 511-524 ◽  
Author(s):  
John R. Hodges ◽  
Karalyn Patterson
Keyword(s):  
Semantic Knowledge ◽  
Semantic Dementia ◽  
Initial Letter ◽  
Sentence Structure ◽  
Opposite Pattern ◽  
Progressive Aphasia ◽  
Visuospatial Skills ◽  
Patient Groups ◽  
Neuropsychological Study ◽  
Phonological Errors

AbstractTwo patients with nonfluent progressive aphasia, who have been studied longitudinally, are contrasted with a group of 5 patients with fluent progressive aphasia or semantic dementia. The most prominent feature of the nonfluent syndrome is the severe distortion of speech output with phonological errors and agrammatic sentence structure. This contrasts with the fluent, well articulated and syntactically correct, but empty, anomic speech found in semantic dementia. Performance on tests of comprehension separates the patient groups: The nonfluent patients show normal single-word comprehension, but marked impairment on tests of syntactic comprehension, while those with semantic dementia demonstrate the opposite pattern. Category fluency is severely defective in semantic dementia, but initial letter-based fluency is more impaired in the nonfluent syndrome. Performance on nonverbally mediated tests of semantic knowledge is impaired in semantic dementia only. The 2 forms of progressive aphasia have in common the sparing of perceptual and visuospatial skills, nonverbal problem solving abilities, and day-to-day (episodic) memory. Neuroradiological investigations have shown marked selective and striking inferolateral left temporal lobe atrophy in all 5 patients with semantic dementia. The changes in nonfluent progressive aphasia appear to be less focal and involve left perisylvian structures more diffusely. These 2 forms of progressive aphasia are, we argue, distinct in their manifestations. (JINS, 1996, 2, 511–524.)

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