An evaluation of recollection and familiarity in Alzheimer’s disease and mild cognitive impairment using receiver operating characteristics

There is a need to investigate exactly how memory breaks down in the course of Alzheimer’s disease (AD). Examining what aspects of memorial processing remain relatively intact early in the disease process will allow us to develop behavioral interventions and possible drug therapies focused on these intact processes. Several recent studies have worked to understand the processes of recollection and familiarity in patients with mild cognitive impairment (MCI) and very mild AD. Although there is general agreement that these patient groups are relatively unable to use recollection to support veridical recognition decisions, there has been some question as to how well these patients can use familiarity. The current study used receiver operating characteristic (ROC) curves and a depth of processing manipulation to understand the effect of MCI and AD on the estimates of recollection and familiarity. Results showed that patients with MCI and AD were impaired in both recollection and familiarity, regardless of the depth of encoding. These results are discussed in relation to disease pathology and in the context of recent conflicting evidence as to whether familiarity remains intact in patients with MCI. The authors highlight differences in stimuli type and task difficulty as possibly modulating the ability of these patients to successfully use familiarity in support of memorial decisions.     

FMRI of two measures of phonological processing in visual word recognition: ecological validity matters

Previous functional magnetic resonance imaging (fMRI) studies have investigated the role of phonological processing by utilizing nonword rhyming decision tasks (e.g., Pugh et al., 1996). Although such tasks clearly engage phonological components of visual word recognition, it is clear that decision tasks are more cognitively involved than the simple overt naming tasks, which more closely map onto normal reading behavior. Our research aim for this study was to examine the advantages of overt naming tasks for fMRI studies of word recognition processes. Process models are presented to highlight the similarities and differences between two cognitive tasks that are used in the word recognition literature, pseudohomophone naming (e.g., pronounce BRANE) and rhyming decision (e.g., do LEAT and JEAT rhyme?). An fMRI study identified several differences in cortical activation associated with the differences observed in the process models. Specifically, the results show that the overt naming task involved the insular cortex and inferior frontal gyrus, whereas the rhyming decision task engaged the temporal-parietal regions. It is argued that future fMRI research examining the neuroanatomical components of basic visual word recognition utilize overt naming tasks.     

Academic Processing Speed Mediates the Influence of Both Externalizing Behavior and Language Skills on the Academic Skills of Students with Emotional Disturbance

The results from previous research suggest that there is a relatively small (albeit statistically significant) relationship between the externalizing behavior and academic skills of students with emotional disturbance (ED). Researchers have also found that the majority of these students have language deficits that hinder their academic performance. The purposes of this study were to investigate the mediating role of academic processing speed (i.e., academic fluency) on the relationship between: (a) The externalizing behavior and academic skills of K-12 students with ED; and (b) language skills and academic skills of students with ED. Results indicate that academic processing speed mediated the influence of both language skills and externalizing behavior on academic skills of this population. The findings, limitations, and implications were discussed.     

Bayesian Risk Assessment in Genetic Testing for Autosomal Dominant Disorders with Age-Dependent Penetrance

Risk assessment is an essential component of genetic counseling and testing, and the accuracy of risk assessment is critical for decision making by consultands. However, it has been shown that genetic risk calculations may have high error rates in practice. Risk calculations for autosomal dominant disorders are frequently complicated by age-dependent penetrance and sensitivities of less than 100% in genetic testing. We provide methods of risk calculation for prototypical pedigrees of a family at risk for an autosomal dominant disorder with age-dependent penetrance. Our risk calculations include scenarios in which the sensitivity of genetic testing is less than 100%, and in which the sensitivity of genetic testing varies for different family members at risk. Our Bayesian methods permit autosomal dominant disease probabilities to be calculated accurately, taking into account all relevant information. Our methods are particularly useful for hereditary cancer syndromes, in which genetic testing can seldom achieve 100% sensitivity. Our methods can be applied to many different scenarios, including those where the sensitivity of genetic testing varies for different family members at risk. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.     

Level validity of self-report whole-family measures

This article introduces an approach to testing the level validity of family assessment instruments (i.e., whether a family instrument measures family functioning at the level of the system it purports to assess). Two parents and 2 adolescents in 69 families rated the warmth in each of their family relationships and in the family as a whole. Family members' ratings of whole-family warmth assessed family functioning not only at the family level (i.e., characteristics of the family as a whole) but also at the individual level of analysis (i.e., characteristics of family members as raters), indicating a lack of level validity. Evidence was provided for the level validity of a latent variable based on family members' ratings of whole-family warmth. The findings underscore the importance of assessing the level validity of individual ratings of whole-family functioning.     

The probability of a given 1-choice structure

A 1-choice structure arises whenever each person in a group chooses exactly one other person according to some criterion. Our purpose is to study the situation in which these choices are made at random. As noted in Harary, Norman and Cartwright [2], such a structure can be represented by a directed graph in which the points represent people and the directed lines their choices. We first describe the shape of such a 1-choice structure, and define its symmetry number. With the help of these properties we are then able to develop and prove a formula which gives a probability of obtaining a given structure in the random choice situation. In order to supply data for these results, we include in the Appendix the diagrams of all 1-choice structures with at most 7 points and the probability of each.The preparation of this article was supported by Grant MH 10834 from the National Institute of Mental Health and Grant 1026-66 from the U. S. Air Force Office of Scientific Research.