Context-processing deficits in schizophrenia: diagnostic specificity, 4-week course,and relationships to clinical symptoms

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia.     

Latent change models of adult cognition: are changes in processing speed and working memory associated with changes in episodic memory?

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.     

Assessing working memory and language comprehension in Alzheimer's disease.

Studies of language impairments in patients with Alzheimer's disease have often assumed that impairments in linguistic working memory underlie comprehension deficits. Assessment of this hypothesis has been hindered both by vagueness of key terms such as "working memory" and by limitations of available working memory tasks, in that many such tasks either seem to have little relationship to language comprehension or are too confusing or difficult for Alzheimer's patients. Four experiments investigated the usefulness of digit ordering, a new task assessing linguistic working memory and/or language processing skill, in normal adults and patients with probable Alzheimer's disease. The digit ordering task was shown to be strongly correlated with the degree of dementia in Alzheimer's patients. The task correlated with measures of language processing on which patients and normal controls performed differently. The results are interpreted as indicating that linguistic representations, linguistic processing, and linguistic working memory are intertwined, such that a deficit of one (e.g., working memory) cannot be said to "cause" a deficit in the other. The implications of this approach are explored in terms of task demands in comprehension and memory measures, and interpretation of previous results in the literature.     

Do novel associative word stem completion and cued recall share the same memory retrieval processes?

The aim of this study was to determine whether word stem completion for novel associations between cue and target words was mediated by automatic unconscious memory processes or effortful memory processes under conscious control. This was done by applying full and divided attention conditions at test to stem completion, cued recall, and recognition, and by administering a questionnaire that probed the memory strategies used by subjects during the completion test. Divided attention had no effect on stem completion performance, but did reduce associative cued recall. Recognition performance was weakened overall by divided attention, but the associative effect was similar under both attention conditions. This suggested that novel associative word stem completion was mediated by automatic retrieval processes. However, the results of the questionnaire indicated that only subjects who attempted to remember the words from the study phase during the completion task showed any novel associative effect. It is concluded that novel association word stem completion and cued recall share automatic retrieval processes, which nevertheless give rise to the experience of remembering.     

An investigation of the accuracy of standardized path coefficients

Given the popular and ever-increasing use of path analytic research paradigms in the social sciences, it is desirable to conduct an investigation into the accuracy of the standardized path coefficients that are often the end-product of these paradigms. In pursuit of this goal, population parameters were preset concerning the correlations between all of the variables and their reliability coefficients. Based on these parameters, thousands of experiments were generated with varying numbers of cases (n). For each experiment, at each level of n, standard path analyses were conducted, and standardized path coefficients were obtained. These standardized path coefficients were then compared against the population path coefficients on which the simulations were based to determine their accuracy. The findings indicate mixed evidence for the accuracy of path analysis research paradigms.     

Examination of the Psychometric Properties of the Spiritual Fitness Assessment

Using a sample of 196 undergraduate students, the present study investigated the psychometric properties of the Spiritual Fitness Assessment, a measure of spiritual fitness designed for use by health and fitness professionals. Examination of inter-item consistency produced satisfactory alpha coefficients for the total test and its three subscales. Correlations of the SFA with measures of spirituality and spiritual well-being provide support for convergent validity. Significant positive correlations with a measure of self-esteem suggest that the test has satisfactory criterion validity. Correlations with age, sex, and a measure of social desirability indicate that the SFA is significantly, though only moderately, affected by demographic variables and motivated response tendencies. Factor analysis of the SFA items indicate that the test is factorially complex and subscales may need to be refined to better measure their intended constructs. Overall, the results of the study suggest that the test may be useful for evaluations of spiritual fitness. Further research with samples drawn from different populations is needed on the test to better establish its reliability and validity.     

A Methodological Examination of Emotion Inductions in Borderline Personality Disorder: A Comparison of Standardized Versus Idiographic Stimuli

Emotional reactivity is conceptualized as a core feature of borderline personality disorder (BPD) and has been subject to substantial empirical research. The laboratory methods used to elicit emotional reactivity in BPD have varied and findings across studies have been mixed. At present, there is little research evaluating the relative efficacy of different methods in eliciting emotional reactivity in BPD. Thus, the current study examined differences in emotional reactivity among individuals with BPD in response to standardized and idiographic stimuli, and across three specific emotions (sadness, fear, and anger). Individuals with BPD, social anxiety disorder, and healthy controls viewed film clips (i.e., standardized stimuli) or engaged in a personally-relevant imagery task (i.e., idiographic stimuli) while self-reported and physiological indices (skin conductance response and respiratory sinus arrhythmia) of emotion were collected. Results indicated that BPD participants displayed greater reactivity of sadness and anger (but not fear) in response to the idiographic versus standardized stimuli, a pattern that was not exhibited by the other two groups. These findings might explain some of the mixed evidence to date and suggest that idiographic sadness and fear inductions may be more effective for individuals with BPD.     

Common and specific cognitive deficits in schizophrenia: relationships to function

The goals of the present study were to assess the interrelationships among tasks from the MATRICS and CNTRACS batteries, to determine the degree to which tasks from each battery capture unique variance in cognitive dysfunction in schizophrenia, and to determine the ability of tasks from each battery to predict functional outcome. Subjects were 104 schizophrenia patients and 132 healthy control subjects recruited as part of the CNTRACS initiative. All subjects completed four CNTRACS tasks and two tasks from the MATRICS battery: Brief Assessment of Cognition in Schizophrenia Symbol Coding and the Hopkins Verbal Learning Test. Functional outcome was also assessed in the schizophrenia subjects. In both the patient and control groups, we found significant intercorrelations between all higher order cognitive tasks (episodic memory, goal maintenance, processing speed, verbal learning) but minimal relationships with the visual task. For almost all tasks, scores were significantly related to measures of functional outcome, with higher associations between CNTRACS tasks and performance-based measures of function and between one of the MATRICS tasks and self-reported functioning, relative to the other functioning measures. After regressing out variance shared by other tasks, we continued to observe group differences in performance among task residuals, particularly for measures of episodic memory from both batteries, although these residuals did not correlate as robustly with functional outcome as raw test scores. These findings suggest that there exists both shared and specific variance across cognitive tasks related to cognitive and functional impairments in schizophrenia and that measures derived from cognitive neuroscience can predict functional capacity and status in schizophrenia.     

Panning for the gold in health research: Incorporating studies’ methodological quality in meta-analysis

Background: Systematic reviews now routinely assess methodological quality to gauge the validity of the included studies and of the synthesis as a whole. Although trends from higher quality studies should be clearer, it is uncertain how often meta-analyses incorporate methodological quality in models of study results either as predictors, or, more interestingly, in interactions with theoretical moderators.

Objective and methods: We survey 200 meta-analyses in three health promotion domains to examine when and how meta-analyses incorporate methodological quality.

Results: Although methodological quality assessments commonly appear in contemporary meta-analyses (usually as scales), they are rarely incorporated in analyses, and still more rarely analysed in interaction with theoretical determinants of the success of health promotions. The few meta-analyses (2.5%) that did include such an interaction analysis showed that moderator results remained significant in higher quality studies or were present only among higher quality studies. We describe how to model quality interactively with theoretically derived moderators and discuss strengths and weaknesses of this approach and in relation to current meta-analytic practice.

Conclusions: In large literatures exhibiting heterogeneous effects, meta-analyses can incorporate methodological quality and generate conclusions that enable greater confidence not only about the substantive phenomenon but also about the role that methodological quality itself plays.