The analysis of repeated-measures data on schizophrenic reaction times using mixture models

1995 ◽  
Vol 14 (8) ◽  
pp. 747-768 ◽  
Author(s):  
Thomas R. Belin ◽  
Donald B. Rubin
Keyword(s):  
Mixture Models ◽  
Repeated Measures ◽  
Reaction Times ◽  
Repeated Measures Data ◽  
Schizophrenic Reaction

Probability-Based and Measurement-Related Hypotheses With Full Restriction for Investigations by Means of Confirmatory Factor Analysis

Methodology ◽  
2011 ◽  
Vol 7 (4) ◽  
pp. 157-164
Author(s):  
Karl Schweizer
Keyword(s):  
Factor Analysis ◽  
Confirmatory Factor Analysis ◽  
Cognitive Processing ◽  
Latent Variables ◽  
Repeated Measures ◽  
Latent Variable ◽  
Model Fit ◽  
Repeated Measures Data ◽  
Confirmatory Factor ◽  
And Performance

Probability-based and measurement-related hypotheses for confirmatory factor analysis of repeated-measures data are investigated. Such hypotheses comprise precise assumptions concerning the relationships among the true components associated with the levels of the design or the items of the measure. Measurement-related hypotheses concentrate on the assumed processes, as, for example, transformation and memory processes, and represent treatment-dependent differences in processing. In contrast, probability-based hypotheses provide the opportunity to consider probabilities as outcome predictions that summarize the effects of various influences. The prediction of performance guided by inexact cues serves as an example. In the empirical part of this paper probability-based and measurement-related hypotheses are applied to working-memory data. Latent variables according to both hypotheses contribute to a good model fit. The best model fit is achieved for the model including latent variables that represented serial cognitive processing and performance according to inexact cues in combination with a latent variable for subsidiary processes.

“Going Backward”: Effects of age and fatigue on posterior-directed falls in Parkinson disease

2021 ◽  
pp. 1-9
Author(s):  
Evan V. Papa ◽  
Rita M. Patterson ◽  
Nicoleta Bugnariu
Keyword(s):  
Postural Control ◽  
Parkinson Disease ◽  
Repeated Measures ◽  
Center Of Pressure ◽  
Angular Displacement ◽  
Reaction Times ◽  
Older Individuals ◽  
Peak Knee ◽  
Significant Difference ◽  
Fatiguing Exercise

BACKGROUND: Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE: We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS: Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS: After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS: The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.

Testing of multivariate repeated measures data with block exchangeable covariance structure

Test ◽  
2017 ◽  
Vol 27 (2) ◽  
pp. 360-378 ◽  
Author(s):  
Ivan Žežula ◽  
Daniel Klein ◽  
Anuradha Roy
Keyword(s):  
Repeated Measures ◽  
Covariance Structure ◽  
Repeated Measures Data

Memory Load, Critical Features and Retrieval Processes in Facial Recognition

1977 ◽  
Vol 45 (3_suppl) ◽  
pp. 1079-1087 ◽  
Author(s):  
Howard B. Orenstein ◽  
Kathy M. Hamilton
Keyword(s):  
College Students ◽  
Repeated Measures ◽  
List Length ◽  
Memory Load ◽  
Facial Recognition ◽  
Reaction Times ◽  
Retrieval Processes ◽  
Factor Design ◽  
Different Response

A Sternberg-type varied set procedure was used in which the set of stimuli associated with the “different” response was, in some cases, large and unspecified. A 3-factor design was used with repeated measures on list length (1, 2, or 4 faces), decision (“same” or “different”), and number of critical features varied between memory and target faces (0, 2, 4, or 7). Reaction times of college students for recognition of faces were analyzed to determine the nature of the retrieval processes employed. Reaction times were faster as the number of feature changes increased, and both parallel and serial processes were indicated for both “same” and “different” responses.

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