The effects of test dimensionality (one-or three-dimensional), distribution shape (normal, positively skewed, or platykurtic), and estimation program (BILOG, MULTILOG, or XCALIBRE) on the accuracy of item and person parameter estimates were assessed. The criterion was the root mean squared error of the difference between estimated and true parameter values. There was an interaction between program and dimensionality, indicating that the robustness of the unidimensionality assumption was a function of the estimation program. With the sample size and test length used, unidimensional estimation programs were insensitive to different shapes of the underlying. distribution. BILOG consistently produced the smallest root mean squared error under most conditions. However, MULTILOG and XCALIBRE showed less variance in parameter estimation due to the violation of unidimensionality, with the exception of estimating the discrimination parameter in MULTILOG. Guidelines for estimating parameters of multidimensional test items using unidimensional item response theory models are suggested.

This study investigates the roles of hippocampal N-methyl-D-aspartate (NMDA) glutamate receptors and CaMKII (calcium/calmodulin-dependent protein kinase II) in amphetamine-produced conditioned place preference (AMPH-CPP) in rats. An earlier report showed that AMPH-CPP resulted in the enhancement of hippocampal CaMKII activity. In this study, AMPH-CPP significantly increased hippocampal GluR1 receptors, though AMPH-CPP was impaired by either blockade of NMDA receptors (AP5) or inhibition of CaMKII (KN-93) during conditioning. These treatments also impaired CPP if administered before testing, but CPP recovered during the next testing session. Therefore, these treatments had no effect on the extinction of CPP. If the conditioned rats were, however, reexposed to AMPH-CPP after a hippocampal-infusion of AP5 or KN-93, the extinction of the original CPP was greater than that seen in the controls. The hippocampal-infusion of D-cycloserine before CPP testing enhanced the extinction of CPP. These results, taken together, indicate that NMDA receptor activation and CaMKII activity are essential for the AMPH-CPP. AMPH-CPP reexposure is similar to the memory reconsolidation process, being disrupted by either a blockade of the NMDA receptor or an inhibition of CaMKII. Furthermore, the extinction of CPP resembles new learning, which is an active process and is facilitated by a partial NMDA agonist.

Our understanding of the relationship between the neuroanatomic loci of brain damage and the incidence of post-stroke depression (PSD) is not complete. Many studies have investigated this relationship and the evidence is conflicting. With the purpose of gaining a consistent, strong, and credible conclusion on the relationship between PSD and the loci of brain damage, a meta-analysis was used in this study to systematically reanalyze the findings of related studies and to investigate the sources of heterogeneity among study results. The key words "stroke or cerebrovascular" and "depression or mood or affective" were entered into the MEDLINE, PsycINFO, and EMBASE databases to search for relevant studies. The references cited in the studies found were also used to locate additional studies. For each eligible study, the important study characteristics were recorded, and the effect sizes of the relationship between PSD and lesion location were computed. Furthermore, we conducted subgroup analyses to explore the heterogeneity among study results. A total of 3,668 patients participating in 52 studies were included in this meta-analysis. There was a weak relationship between PSD and right hemisphere lesion. The major sources of heterogeneous study results included systematic exclusion of patients with language dysfunction and use of different assessors and instruments for diagnosing depression. Future efforts should aim to enhance standards for reporting studies, improve assessment tools for assessing depression of aphasic patients, and adopt appropriate study methodologies for investigating the relationship between PSD and lesion location.

This study investigated the functional performance of two major subtypes of dementia, Alzheimer's disease (AD) and vascular dementia (VaD), by the Functional Independence Measure (FIM), and to understand the need for assistance in performing activities of daily living. The subjects comprised 64 AD and 21 VaD patients who were recruited from two epidemiologic studies of dementia with a total of 3,931 community residents aged 65 years and above in southern Taiwan. The results showed that the severity of dementia was similar between the two groups. The mean score for AD was 82.7 and for VaD was 56.5 for total FIM (p < 0.05), 61.6 and 41.7 for the motor dimension (p < 0.05), and 21.1 and 15.7 for the cognitive dimension (p < 0.05). There were significant differences (p < 0.01) between AD and VaD in six FIM items and borderline or marginal significance (p < 0.05) in most of the FIM items. For AD patients, stairs, lower dressing, bathing, and tub/shower transfer were the most difficult items in the motor dimension, and it was memory in the cognitive dimension. For VaD patients, bathing, upper and lower dressing, and grooming were the most difficult items in the motor dimension, and it was problem solving in the cognitive dimension. VaD patients were more dependent on all FIM items and required more assistance than AD patients. The functional performances of dementia patients were significantly associated with dementia severity and subtypes, together accounting for 40% of the variability in total FIM. In conclusion, most dementia patients are dependent in daily activities and different types and severity of dementia lead to different disability profiles; individualized care is, therefore, most appropriate.

ABSTRACT:The goal of this study was to use meta-analytic path analysis to evaluate a theoretical model of stress and health. A meta-analysis technique was adopted to combine and re-analyze 477 studies that investigated stress-related topics between January 1980 and December 2003 in Taiwan. Databases searched included PerioPath-Index to Chinese Periodical Literature, Electronic Theses and Dissertations System, and NSC (National Science Council) Science and Technology Information System. Variables recorded included stress, health, social support, coping strategies, and personality traits. A correlation matrix of these variables was derived from meta-analytic data and then analyzed using structural path analysis to test the fitness of the hypothesized stress-health model to the observed aggregated data. Results showed the revised hypothesized model to be a reasonable, good fit to aggregated data. Based on the theoretical stress-health model developed in this study, subjective stress was found to have a substantively important and direct effect on health, whereas objective stress required the mediating function of subjective stress to exercise an influence on health. Such variables as social support, coping strategies, and personality traits had comparatively weaker influences, either direct or indirect, on the stress-health process. This study provided a holistic view on the relationship between stress and health in the context of stress and proposed a direction for future research and practice.