Neuropsychological differentiation of progressive aphasic disorders

The differentiation of subtypes of primary progressive aphasia (PPA) remains challenging. We aimed to identify optimum neuropsychological measures for characterizing PPA, to examine the relationship between behavioural change and subtypes of PPA and to determine whether characteristic profiles of language, working memory, and behavioural changes occur in PPA. Forty-seven patients with PPA and multi-domain Alzheimer's disease (AD) together with 19 age-matched controls underwent a large battery of working memory and language tests. We found that simple tasks of sentence ordering, narrative production, and buccofacial praxis were particularly useful in differentiating non-fluent/agrammatic variant PPA (nfvPPA) from other PPA subtypes, whereas a test of single word comprehension was useful in detecting semantic dementia (SD). No individual tests were discriminating for logopenic variant PPA (lvPPA) relative to nfvPPA. LvPPA and multidomain AD exhibited similar language profiles. A principal components analysis revealed that characteristic PPA profiles extended beyond the realms of language, in particular, the presence of apraxia in nfvPPA, behavioural changes in SD, and working memory deficits in lvPPA. These findings suggest that not all tests are equally discriminatory for PPA and highlight the importance of a test profile in differentiating PPA. These results also support the view that lvPPA is a focal form of AD and emphasize the difficulties classifying lvPPA.     

The effect of contrast upon perceived speed: a general phenomenon?

The perceived speed of a grating pattern has often been reported to slow as the contrast of the pattern is reduced (though there are some contradictory reports). The mechanism of this perceived slowing has not yet been established nor have the conditions under which the effect occurs (or does not occur). We have therefore examined a range of stimuli that differ upon such aspects as one versus two dimensions, periodic versus nonperiodic, and whether the stimuli occur within a static window. We have also examined a range of stimulus speeds, different types of motion, and simultaneous versus successive presentations. We have found evidence for contrast-induced changes in perceived speed in all our stimuli, and thus suggest that none of the stimulus factors listed above is critical in producing the effect. Though the pattern of results is complex and shows substantial intersubject variation, we generally found that slowly moving patterns presented simultaneously produced the greatest decrease in perceived speed with decreasing contrast. On the other hand faster speeds and successive presentation produced more veridical matches or even an increase in perceived speed with decreasing contrast.     

Suppressive interactions between moving patterns: role of velocity

Detection and use of motion in complex environments requires movement measurements to be combined. The role of velocity in the suppressive interaction between patterns that move in orthogonal directions was assessed. When dmax was measured, it was found that a range of medium to high speeds of vertical motion all had a suppressive effect upon detecting horizontal motion. When dmin was measured, only a range of low velocities caused a disruption of performance. Thus, whilst velocity is an important parameter in determining the size of the suppressive effect, it has nonparallel influences at the upper and lower end of the displacement range.     

A Meta-Analysis of the Reliability of Free and For-Pay Big Five Scales

The present study meta-analytically compared coefficient alpha reliabilities reported for free and for-pay Big Five scales. We collected 288 studies from five previous meta-analyses of Big Five traits and harvested 1,317 alphas from these studies. We found that free and for-pay scales measuring Big Five traits possessed comparable reliabilities. However, after we controlled for the numbers of items in the scales with the Spearman-Brown formula, we found that free scales possessed significantly higher alpha coefficients than for-pay scales for each of the Big Five traits. Thus, the study offers initial evidence that Big Five scales that are free more efficiently measure these traits for research purposes than do for-pay scales.     

Psychosocial discontinuities introduced by the new reproductive technologies

The introduction of the new reproductive technologies has brought about a separation of the experience of reproduction from a previously necessary act of sexual intercourse between a fertile male and a fertile female. This has brought in its train the need for new ways of thinking about the relationship between procreation, reproduction and parenting. Psychosocial research into child–parent, male–female and kin relationships resulting from the use of the new reproductive technologies has value both in terms of its own intrinsic interest and also in terms of insights provided into what has been traditionally portrayed as the ‘normal’ reproductive process. This contribution to the Special Issue serves as a general introduction to the topic by presenting a ‘discontinuity’ model intended to provide a context in which psychosocial research into the provision and use of the new reproductive technologies could be explored. © 1998 John Wiley & Sons, Ltd.     

A taxometric analysis of the Psychopathy Checklist: Screening Version (PCL:SV): further evidence of dimensionality

A taxometric analysis of the Psychopathy Checklist: Screening Version (PCL:SV; S. D. Hart, D. N. Cox, & R. D. Hare, 1995) was performed on a group of 2,250 male and female forensic/psychiatric patients and jail/prison inmates. The 4 PCL:SV facet scores (Interpersonal, Affective, Impulsive Lifestyle, Antisocial Behavior) served as indicators in this study, and the data were analyzed with 3 principal taxometric procedures--mean above minus below a cut, maximum eigenvalue, and latent mode factor analysis. The results show evidence of dimensional structure on the PCL:SV in the full sample as well as in all 8 subsamples (men, women, Whites, Blacks, hospital patients, jail/prison inmates, file review with an interview, file review without an interview). These findings corroborate recent taxometric research on the Psychopathy Checklist-Revised (R. D. Hare, 1991, 2003) in which results have been largely dimensional in nature. It is concluded that scores on the PCL:SV differ quantitatively as points on a dimension (high vs. low psychopathy) rather than partitioning into qualitatively distinct categories of behavior (psychopath vs. nonpsychopath).     

Predicting future reconviction in offenders with intellectual disabilities: the predictive efficacy of VRAG, PCL-SV, and the HCR-20

Accurate predictions of future reconviction, including those for violent crimes, have been shown to be greatly aided by the use of formal risk assessment instruments. However, it is unclear as to whether these instruments would also be predictive in a sample of offenders with intellectual disabilities. In this study, the authors have shown that the Violence Risk Appraisal Guide (V. L. Quinsey, G. T. Harris, M. E. Rice, & C. Cormier, 1998); the Psychopathy Checklist--Screening Version (S. D. Hart, D. N. Cox, & R. D. Hare, 1995); and the History, Clinical, Risk Management--20 (C. D. Webster, K. S. Douglas, D. Eaves, & S. D. Hart, 1997) were all significant predictors of violent and general reconviction in this sample, and in many cases, their efficacy was greater than in a control sample of mentally disordered offenders without an intellectual disability.     

Faking of the Implicit Association Test Is Statistically Detectable and Partly Correctable

Male and female participants were instructed to produce an altered response pattern on an Implicit Association Test measure of gender identity by slowing performance in trials requiring the same response to stimuli designating own gender and self. Participants' faking success was found to be predictable by a measure of slowing relative to unfaked performances. This combined task slowing (CTS) indicator was then applied in reanalyses of three experiments from other laboratories, two involving instructed faking and one involving possibly motivated faking. Across all studies involving instructed faking, CTS correctly classified 75% of intentionally faking participants. Using the CTS index to adjust faked Implicit Association Test scores increased the correlation of CTS-adjusted measures with known group membership, relative to unadjusted (i.e., faked) measures.