Biomedical subjects

D A Brodeur

Publications and source records attributed to D A Brodeur.

4 recordsLinked to original sources

PubMed2001

The development of selective attention in children with attention deficit hyperactivity disorder.

The influence of age on a selective attention task was studied in a sample of children with and without Attention Deficit Hyperactivity Disorder (ADHD). The impact of methylphenidate (MPH) treatment on selective attention was also investigated in the children with ADHD. Two age groups of children with ADHD and two age groups of control children were tested using a timed computer task. The task consisted of identifying visual target stimuli under various distracter conditions. Distracters varied on the basis of modality (i.e., visual, auditory, or both) and task relevance (i.e., meaningful or irrelevant). Reaction times and accuracy were measured. Children with ADHD were less efficient on the selective attention task than were children without ADHD, and older children were more efficient than younger children in both groups. Children without ADHD were influenced more by the nature of distracters than were children with ADHD. For children with ADHD, MPH improved performance overall.

Age Factors↗

PubMed1997

Covert visual orienting across the lifespan.

Covert visual orienting was examined over a span of human life ranging from six to 73 years. The observer's task was the speeded discrimination of "X" from "O1" but of primary interest was the effect of a location cue that appeared prior to the target. Both an abrupt stimulus cue and a voluntary information cue were studied using response time (RT) measures. Eye movements were monitored to control for differences in the ability to maintain fixation. Experiment 1 showed that there were very few age differences in stimulus-cued orienting. In contrast, there were important differences when orienting was intentional. In comparison with young adults, children were less able to sustain orienting over time, and senior adults required more time to use the cue. Experiment 2 tested the relation between stimulus and information cues when they both occurred prior to a given target. All age groups were able to use information cues in the presence of conflicting stimulus cues, but young adults were better able to do so than either children or senior adults. These results are interpreted as support for the view that separate mechanisms underlie stimulus-based versus information-based spatial orienting.

Adolescent↗

PubMed1989

A developmental study of covert orienting to peripheral visual cues.

Observers aged 6, 8, and 20 years participated in a speeded classification task designed to measure covert shifts of visual attention. On each trial observers responded to a target which appeared in one of three locations arrayed horizontally across the display. Three prestimulus cues were employed: neutral (the cue was present in all three possible target locations), unpredictable (the cue was present in the target location on a random basis), and predictable (the cue was present in the target location on 80% of the trials). There were four developmental findings: (1) Observers of all ages oriented attention automatically to the cued locations, (2) children processed targets in non-cued locations more slowly than adults, (3) only adults took advantage of the predictability of the cue, and (4) all age groups provided evidence that strategic orienting competes with response priming for cognitive resources. The implications of these findings for theories of attentional development are discussed.

Adult↗

PubMedDate not supplied

Visual processing of verbal and nonverbal stimuli in adolescents with reading disabilities.

This study investigated whether a group of children with reading disabilities (RD) were slower at processing visual information in general (compared to a group of children of comparable age and a group of children of comparable reading level), or whether their deficit was specific to the written word. Computerized backward masking and temporal integration tasks were used to assess the speed of visual information processing. Stimulus complexity (simple, complex) and type (verbal, nonverbal) were varied, creating a 2 x 2 matrix of stimulus conditions: simple nonverbal, complex nonverbal, simple verbal, and complex verbal. Adolescents with RD demonstrated difficulties in processing rapidly presented verbal and nonverbal visual stimuli, although the effect was magnified when they were processing verbal stimuli. Thus, the results of this study suggest that some youth with reading disabilities have visual temporal processing deficits that compound difficulties in processing verbal information during reading.

Adolescent↗