Factor analysis of the self-report Dysexecutive (DEX-S) Questionnaire.

The self-rating Dysexecutive Questionnaire (DEX-S) is a recently developed standardized self-report measure of behavioral difficulties associated with executive functioning such as impulsivity, inhibition control, monitoring, and planning. Few studies have examined its construct validity, particularly for its potential wider use across a variety of clinical and nonclinical populations. This study examines the factor structure of the DEX-S questionnaire using a sample of nonclinical (N = 293) and clinical (N = 49) participants.

A commentary on the impacts of metals and metalloids in the environment upon the metabolism of drugs and chemicals.

The salient feature of metals is that unlike organic compounds they do not degrade in the environment and barely move from one environmental matrix to another. Human interventions take these compounds from their stable and non-bioavailable geological matrix into situations of biological accessibility. Studies in the 1970s and the 1980s of metal bioavailability and impacts of metals and metalloids were driven by the process of abatement of lead in the environment.

Lateralization of speech production using verbal/manual dual tasks: meta-analysis of sex differences and practice effects.

The present paper reviews the findings of 30 years of verbal/manual dual task studies, the method most commonly used to assess lateralization of speech production in non-clinical samples. Meta-analysis of 64 results revealed that both the type of manual task used and the nature of practice that is given influence the size of the laterality effect. A meta-analysis of 36 results examining the effect size of sex differences in estimates of lateralization of speech production indicated that males appear to show slightly larger laterality effects than females.

Effects of memory load and distraction on performance and event-related slow potentials in a visuospatial working memory task.

Brain electrical activity related to working memory was recorded at 15 scalp electrodes during a visuospatial delayed response task. Participants (N = 18) touched the remembered position of a target on a computer screen after either a 1 or 8 sec delay. These memory trials were compared to sensory trials in which the target remained present throughout the delay and response periods.

Test-retest reliability of a new form of the auditory verbal learning test (AVLT).

The equivalence between the original form (Form 1) of the Auditory Verbal Learning Test (AVLT), and a new form (Form 4) was examined in 51 normal adult subjects (20-67 years) of average estimated intelligence who were assessed in two separate sessions. Performance on the new form was equivalent to that on the original and most measures on the two tests showed significant positive correlations. Test-retest reliability of AVLT scores between sessions was also assessed, both globally and separately for Form 1 followed by Form 4 and for the reverse order.

Auditory verbal learning test components as measures of the severity of closed-head injury.

Auditory verbal learning and memory was assessed in 18 patients with moderate-severe closed-head injury (CHI). Compared to a matched control group, performance of the CHI subjects on all measures of the Auditory Verbal Learning Test (AVLT) was significantly worse. Discriminant function analysis correctly classified 90% of subjects as CHI or control using the three most reliable measures of the AVLT.