Confirmation of an Inhibitory Control Deficit in Attention-Deficit/Hyperactivity Disorder

The objective of this study was to determine whether deficient inhibitory control distinguishes children with a diagnosis of attention-deficit/hyperactivity (ADHD) disorder, conduct disorder (CD), and comorbid ADHD + CD from normally developing children. Participants were rigorously diagnosed children (age 7 to 12 years) with ADHD (N = 72), CD (N = 13) or ADHD + CD (N = 47) and 33 control children (NC). We studied inhibitory control using the stop-signal paradigm, a laboratory task that assessed the ability to inhibit an ongoing action. The ADHD group had significantly impaired inhibitory control compared to NC, CD, and ADHD + CD children. These results indicate that children with ADHD have deficient inhibition as measured in the stop-signal paradigm and that ADHD occurring in the presence of ADHD + CD may represent a phenocopy of CD rather than a variant of ADHD.     

Language comprehension and probe-list memory

Experiments were performed using probe-word recognition methodology in which participants read sentences that were presented 1 word at a time and were then shown a probe word and had to make a speeded response indicating whether the word had occurred in the sentence. One experiment showed that response times to probe words increased with the size of the set of candidate probes. The other experiments showed that the effects caused by name repetition in circumstances in which the repeated name was co-referential also occurred when the repeated name was not co-referential and when the order of words in a sentence was scrambled. The results suggest that responses in the task can be based on probe-list memory, a mental representation created to keep track of those words that the participant believes are likely to be probed, and that the use of the task to make inferences about language comprehension should be accompanied by controls ruling out such strategies.     

Dyslexia linked to talent: global visual-spatial ability

Dyslexia has long been defined by deficit. Nevertheless, the view that visual-spatial talents accompany dyslexia has grown, due to reports of individuals with dyslexia who possess visual-spatial strengths, findings of elevated incidence of dyslexia in certain visual-spatial professions, and the hypothesis that left-hemisphere deficits accompany right-hemisphere strengths. Studies have reported superior, inferior, and average levels of visual-spatial abilities associated with dyslexia. In two investigations, we found an association between dyslexia and speed of recognition of impossible figures, a global visual-spatial task. This finding suggests that dyslexia is associated with a particular type of visual-spatial talent-enhanced ability to process visual-spatial information globally (holistically) rather than locally (part by part).     

A preliminary study of self-esteem,stigma, and disclosure in adolescents who stutter

This study examined the self-esteem, perceived stigma, and disclosure practices of 48 adolescents who stutter divided into two age cohorts: younger (13, 14, and 15 years) and older (16, 17, and 18 years) adolescents. Results revealed that 41 (85%) of the participants scored within 1 S.D. from the mean on a standardized measure of self-esteem, indicative of positive self-esteem. Results also showed that stuttering did not present a stigmatizing condition for the majority (65%) of adolescents who stutter. However, 60% of participants indicated that they "rarely" or "never" discussed their stuttering. The younger adolescents perceived stuttering as a more negative and stigmatizing condition than older adolescents. Implications for understanding stuttering in adolescents are discussed. EDUCATIONAL OBJECTIVES: Readers will learn about and understand (a) the role of stigma, disclosure, and self-esteem in stuttering; (b) the methods used to evaluate stigma, disclosure, and self-esteem in adolescents; and (c) the similarities between adolescents who stutter and normative data on self-esteem and stigma scales.     

Selective inhibition in children with attention-deficit hyperactivity disorder off and on stimulant medication

Selective inhibition requires discrimination between auditory signals and is assessed using a modification of the stop-signal task. Selective inhibition was assessed in a group of 59 clinic-referred, DSM-IV-diagnosed children with attention-deficit hyperactivity disorder (ADHD) and compared to that of a community sample of 59 children. Methylphenidate (MPH) effects on selective inhibition were assessed in a subset of the ADHD sample that participated in an acute, randomized, placebo-controlled, crossover trial with 3 fixed doses of MPH. Children with ADHD performed more poorly than controls on the majority of selective stop-signal task parameters: they exhibited more anticipatory (invalid) responses, with less accurate and more variable responses on the response execution task, as well as a slower selective inhibition process. MPH improved speed of both inhibition and response execution processes; it also reduced variability of response execution and decreased nonselective inhibition. On the one hand, findings are consistent with purported inhibition deficit in ADHD, but on the other hand, suggest that neither the impairment itself, nor MPH effects, were restricted to inhibition.     

Post-traumatic stress disorder symptoms in United Nations peacekeepers: an examination of factor structure in peacekeepers with and without chronic pain

Recent factor analytic investigations of post-traumatic stress disorder in military veterans suggest that symptoms are best described by either a hierarchical 2-factor model or a 4-factor inter-correlated model. Other recent evidence suggests that post-traumatic stress disorder and chronic pain are intricately related; however, the nature of this relationship is not well understood. Factor analysis provides one method for clarifying this relationship. In study 1, we compared competing models of post-traumatic stress disorder symptom structure in a sample of 400 male United Nations peacekeepers using confirmatory factor analysis. Results indicated that both the hierarchical 2-factor and the 4-factor inter-correlated models provided good fit to the data. In study 2, the reliability of these models was assessed in 427 male United Nations peacekeepers with chronic back pain and 341 without. Group comparisons of the confirmatory factor analysis results revealed that the structure of the hierarchical 2-factor and 4-factor inter-correlated models both provided good fit to the data in both the chronic back pain and the group without. However, the structure of the models for the group with chronic back pain group differed in significant ways from that of the group without chronic back pain. Post-traumatic stress disorder symptoms in military veterans can be adequately conceptualized using either a hierarchical 2-factor or 4-factor inter-correlated model. Chronic pain has a minimal influence on overall factor structure. The hierarchical 2-factor model, while parsimonious, does not provide the degree of symptom detail provided by the 4-factor inter-correlated model. Implications for conceptualization of post-traumatic stress disorder symptoms for patients with chronic back pain and significant post-traumatic stress disorder symptomatology are discussed.     

Repetition priming mediated by task similarity in semantic classification

In the present study, the specificity of repetition priming between semantic classification tasks was examined using Osgood's (Osgood, Suci, & Tannenbaum, 1957) semantic space as a heuristic for determining the similarity between classifications. The classification tasks involved judging the meaning of words on semantic scales, such as pleasant/unpleasant. The amount of priming across classifications was hypothesized to decrease with increasing distance (decreasing similarity) between semantic scales in connotative semantic space. The results showed maximum repetition priming when the study and the test classifications were the same, intermediate degrees of priming when the study and the test classification scales shared loadings on semantic factors, and little priming when the study and the test classification scales loaded primarily on orthogonal semantic factors--that is, when the distance between scales was maximized. Consistent with the transfer-appropriate processing framework, repetition priming in semantic classifications was highly task specific, decreasing with increasing distance between classification scales.