Metabolic Syndrome and Cognitive Function in Healthy Middle-Aged and Older Adults without Diabetes

ABSTRACT

Objective: Few studies have addressed whether the metabolic syndrome (MetS) and its individual components are associated with cognitive function in middle-aged and older populations, as well as whether specific areas of cognition are more affected than others. We examined the cross-sectional association between MetS and six areas of cognitive function in healthy cognitively intact adults without diabetes (n?=?853, mean age 61 years) randomized in two intervention trials. Methods: The National Cholesterol Education Program (NCEP) criteria were used to identify subjects with MetS. Cognitive function was assessed with a neuropsychological battery. A principal components analysis was used to extract five uncorrelated factors interpreted to represent five areas of cognition, and a measure of global cognition was calculated. Results: MetS was weakly but non-significantly associated with lower verbal learning (β?=??.14 [SE(β)?=?0.09], p?=?.15). As the number of MetS criteria increased, scores on global cognition (p trend?=?.01), verbal learning (p trend?=?.06) and semantic memory (p trend?=?.04) decreased. Hypertension was the only MetS risk factor that was independently correlated with lower verbal learning (β?=??.17 [SE(β) =?0.08], p?=?.04), semantic memory (β?=??.26 [SE(β)?=?0.08], p?=?.001) and global cognition (β?=??.15 [SE(β)?=?0.07], p?=?.04). Conclusion: This study adds to the evidence of an association between MetS and lower cognitive function among healthy middle-aged and older adults without CVD and diabetes, as well as confirms the correlation between hypertension and lower cognition.     

Surface perception in pictures

Subjects adjusted a local gauge figure such as to perceptually “fit” the apparent surfaces of objects depicted in photographs. We obtained a few hundred data points per session, covering the picture according to a uniform lattice. Settings were repeated 3 times for each of 3 subjects. Almost all of the variability resided in the slant; the relative spread in the slant was about 25% (Weber fraction). The tilt was reproduced with a typical spread of about 10?. The rank correlation of the slant settings of different observers was high, thus the slant settings of different subjects were monotonically related. The variability could be predicted from the scatter in repeated settings by the individual observers. Although repeated settings by a single observer agreed within 5%, observers did not agree on the value of the slant, even on the average. Scaling factors of a doubling in the depth dimension were encountered between different subjects. The data conformed quite well to some hypothetical fiducial global surface, the orientation of which was “probed” by the subject’s local settings. The variability was completely accounted for by singleobserver scatter. These conclusions are based upon an analysis of the internal structure of the local settings. We did not address the problem of veridicality, that is, conformity to some “real object.”     

Dynamic factor analysis of nonstationary multivariate time series

A dynamic factor model is proposed for the analysis of multivariate nonstationary time series in the time domain. The nonstationarity in the series is represented by a linear time dependent mean function. This mild form of nonstationarity is often relevant in analyzing socio-economic time series met in practice. Through the use of an extended version of Molenaar's stationary dynamic factor analysis method, the effect of nonstationarity on the latent factor series is incorporated in the dynamic nonstationary factor model (DNFM). It is shown that the estimation of the unknown parameters in this model can be easily carried out by reformulating the DNFM as a covariance structure model and adopting the ML algorithm proposed by Jöreskog. Furthermore, an empirical example is given to demonstrate the usefulness of the proposed DNFM and the analysis.     

Response selection in visual search: the influence of response compatibility of nontargets

The authors used visual search tasks in which components of the classic flanker task (B. A. Eriksen & C. W. Eriksen, 1974) were introduced. In several experiments the authors obtained evidence of parallel search for a target among distractor elements. Therefore, 2-stage models of visual search predict no effect of the identity of those distractors. However, clear compatibility effects of the distractors were obtained: Responses were faster when the distractors were compatible with the response than when they were incompatible. These results show that even in parallel search tasks identity information is extracted from the distractors. In addition, alternative interpretations of the results in terms of the occasional identification of a distractor before or after the target was identified could be ruled out. The results showed that flat search slopes obtained in visual search experiments provide no benchmark for preattentive processing.     

Learning and strain among newcomers: a three-wave study on the effects of job demands and job control

The present 3-wave longitudinal study was an examination of job-related learning and strain as a function of job demand and job control. The participants were 311 newcomers to their jobs. On the basis of R. A. Karasek and T. Theorell's (1990) demand-control model, the authors predicted that high demand and high job control would lead to high levels of learning; low demand and low job control should lead to low levels of learning; high demand and low job control should lead to high levels of strain; and low demand and high job control should lead to low levels of strain. The relation between strain and learning was also examined. The authors tested the hypotheses using ANCOVA and structural equation modeling. The results revealed that high levels of strain have an adverse effect on learning; the reverse effect was not confirmed. It appears that Karasek and Theorell's model is very relevant when examining work socialization processes.     

Representation-hunger reconsidered

According to a standard representationalist view cognitive capacities depend on internal content-carrying states. Recent alternatives to this view have been met with the reaction that they have, at best, limited scope, because a large range of cognitive phenomena—those involving absent and abstract features—require representational explanations. Here we challenge the idea that the consideration of cognition regarding the absent and the abstract can move the debate about representationalism along. Whether or not cognition involving the absent and the abstract requires the positing of representations depends upon whether more basic forms of cognition require the positing of representations.