Sensitivity of the Informant Questionnaire on Cognitive Decline: An Application of Item Response Theory

ABSTRACT

The Informant Questionnaire on Cognitive Decline (IQCODE) is a formal informant report instrument, originally developed by Jorm and Jacomb (1989 Jorm, A. F. and Jacomb, P. A. 1989. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): Socio-demographic correlates, reliability, validity and some norms. Psychological Medicine, 19(4): 1015–1022. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Psychological Medicine, 19(4), 1015). The goal of the present study was to evaluate the range of cognitive decline in which the IQCODE is most sensitive, using item response theory (IRT). Existing data (N = 740) from a sample of community-dwelling older adults was used for this purpose. A 2-parameter model estimating item difficulty and discrimination fit the data best. Additionally, the IQCODE provided the most psychometric information in the range of ?0.5 < θ < 1.5, with peak information obtained at approximately θ = 0.4. Based on individuals' latent score (θ) estimates, items on the IQCODE are adequate for use as a screening tool for dementia. Results of the item calibration may be useful for targeted assessment needs, such as the development of short forms.     

Age-related Changes in Memory and Fluid Reasoning in a Sample of Healthy Old People

ABSTRACT

Participants in the Healthy Old People in Edinburgh (HOPE) study (N = 398) were assessed on Raven's Progressive Matrices and Logical Memory on up to three occasions. Covariates included education, social class, disease and medication status, blood pressure and study outcome. Raven's score declined linearly with age, whereas decline in Logical Memory was accelerating. There was significant variation in individuals' rates of decline for Ravens but not Logical Memory. Slope–intercept covariances were not significant. Those who later developed dementia already exhibited lower scores, more so for Logical Memory than Raven's. Death and study attrition were related to performance, again greater for Logical Memory. Conclusions: The HOPE approach of progressive screening is a feasible and practical method for studying healthy cognitive ageing. As predicted for an initially healthy sample, rates of decline were relatively homogeneous. The hypothesis of differential decline was not supported, nor was a strict interpretation of the hypothesis that cognitive ageing is entirely pathology driven.     

Activity experiences shape perceived fitness trajectories: Results from a 6-month randomized controlled trial in older women

ABSTRACT

In this study we addressed the subjective benefits of activity interventions that were designed to improve cognitive fitness in old age. Two hundred and fifty-nine women (aged 70–93 years) were randomized to participate in an exercise or a computer course or a control condition for 6 months. Subjective ratings of the perceived change of cognitive and physical fitness components were captured before, during, after the intervention interval, and at a 10-month follow-up. Positive and negative affect levels and objective cognitive fitness parameters served as possible covariates. Multilevel modeling revealed that the computer group rated memory and concentration as having improved at 4 months and again at 6 months. The exercise group, in contrast, perceived physical capacities as maintained or improved. The characteristics of the activity experience seem to determine the perceived fitness changes. We conclude that actual learning experiences improve one's self-concept of abilities.     

Age-related differences in word-retrieval but not in meaning generation

ABSTRACT

This study examines age-associated changes in retrieval on a picture-naming task, phonemic and semantic fluency tasks, and the Homophone Meaning Generation Test (HMGT). The sample included 152 Hebrew-speaking adults, half young (mean age 22.75) and half old (mean age 76.05). Groups differed on the picture-naming task and on both verbal fluency tasks, but not on the HMGT. Age explained a greater share of the variance than did education level on these three tests, whereas the opposite pattern of results was seen on the HMGT. We suggest that age-related word finding difficulties are attenuated when performance allows for semantic rather than phonological access.     

Towards a new method for bridging the gap between “smart” infants and “dumb” preschoolers

Based on violation-of-expectation (VoE) paradigms, amazing cognitive competencies have been demonstrated in young infants, which could not be shown in toddlers or even preschoolers. This divergence might as much be caused by different research methods as by discontinuities in development. As looking-time measures are not readily applicable to older children, we suggest a new method that is suitable for children from two years of age onwards. In an empirical examination of this method, 26 children aged 2–7 years learned by trial and error to always find a target picture among a pair of pictures. Each target picture was an impossible version of the non-target picture. After reaching a learning criterion, children had to generalize the learned concept to pictures belonging to a different category. Results showed that even the youngest participants reached the learning criterion and were able to apply what they had learned to another category.     

Spatial memory and explicit knowledge: An effect of instruction on representational momentum

Freyd (1987; Finke & Freyd, 1985) suggested that representational momentum (i.e., forward displacement in memory for the location of a moving target) is impervious to error feedback (i.e., is modular or cognitively impenetrable), but studies supporting this claim might not have allowed sufficient opportunity for learning to occur. In the experiment reported here, participants were (a) naïve regarding representational momentum, (b) informed about representational momentum but not instructed to counteract it, or (c) informed about representational momentum and instructed to counteract it. All participants exhibited significant displacement. However, participants informed about representational momentum exhibited less forward displacement than did naïve participants due to a greater tendency to respond same to probes behind the true–same position. Possible mechanisms of compensation and the notion that displacement reflects both modular (cognitively impenetrable) and nonmodular (cognitively penetrable) components are addressed.     

Processing fluency as a predictor of salience asymmetries in the Implicit Association Test

The Implicit Association Test (IAT) is the most popular indirect measure of attitudes in social psychology. Rothermund and Wentura (2001, 2004) suggested that artifacts such as salience asymmetries are a source of compatibility effects in the IAT, and, therefore, the IAT does not necessarily measure attitude. They claim that salience asymmetries correspond with visual search asymmetries, such that the stimulus categories that are more quickly detected in a visual search task are also compatible in the IAT. We propose that processing fluency is a more reliable indicator of salience asymmetries in the IAT than are visual search asymmetries. To test this hypothesis, we set processing fluency in opposition to visual search asymmetry to see which variable better predicted IAT effects. In one pair of categories, the category that was more quickly detected in visual search was also more fluently processed in a binary classification task. In a second pair of categories, the category that was more quickly detected in visual search was the less fluently processed category. Across four experiments, we demonstrated that compatibility effects in the IAT corresponded with differences in processing fluency between categories, rather than with visual search asymmetries.     

Impaired task switching performance in children with dyslexia but not in children with autism

Problems with cognitive control in both autism and dyslexia have already been reported in different studies. The present study specifically examined task-switching performance in children with autism and dyslexia. For this purpose, a multiple-trial paradigm was used with cues for colour- and shape-matching tasks presented before a run of trials. The cue could imply a task switch (when the cue changed the task) or a task repetition (when the cue did not change the task). Both reaction times and error rates were measured for switching, restarting, and general task performance. Participants were children with autism (24) and with dyslexia (25) and healthy controls (27) with normal IQ and ages from 12 to 18 years. The main finding was that while similar switching performance was observed between children with autism and the healthy controls, children with dyslexia showed a significant switch-specific delay relative to both healthy controls and children with autism. Furthermore, no deficit in restarting performance was observed for any of the two patient groups. Finally, additional evidence is provided for a more general deficit in information processing in dyslexia. Our data suggest that children with autism are able to switch between tasks in a similar way as do normally developing children as long as the tasks are unambiguously specified. Furthermore, the data imply switch-specific deficits in dyslexia additionally to the deficits in general information processing already reported in the literature. The implications of our data are further discussed in relation to the interpretation of the Wisconsin Card Sorting Test.     

The 36th Sir Frederick Bartlett Lecture: An associative analysis of spatial learning

The ability of animals to find important goals in their environment has been said to require a form of learning that is qualitatively different from that normally studied in the conditioning laboratory. Such spatial learning has been said to depend upon the construction of a global representation of the environment, and the acquisition of knowledge about the position of goals with reference to this representation is said to be unaffected by the presence of other cues or landmarks. To evaluate the first of these claims, experiments are described that investigated the extent to which the effects of training in one environment transfer to another. To evaluate the second claim, experiments are described that investigated whether cue competition effects normally found in conditioning studies can be found in spatial tasks. Overall, the results indicate that most of the phenomena of spatial learning can be explained by the principles of associative learning. The implications of the reported results for an understanding of the neural mechanisms of spatial learning are considered.     

Enhanced processing fluency leads to biases in source memory

The present experiments were conducted to determine whether processing fluency affects source memory decisions. In the first three experiments, participants decided whether test items appeared in the same sensory modality (Experiments 1A, 1B) or perceptual form (font type, Experiment 2) at study and test. The results were consistent across the three studies and showed that perceptual priming leads to an increase in reports that stimuli were presented in the same sensory or perceptual form during the study and test phase. Experiment 3 showed that conceptual fluency affects source attributions in much the same way as perceptual fluency, and Experiment 4 showed that fluency is associated with a subjective experience of familiarity even when it might serve as a basis for source inference. These results are consistent with recent neuropsychological and neuroimaging evidence that familiarity-based processes contribute to source memory decisions under some circumstances, such as when items and contexts are unitized rather than merely bound together at encoding.