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Covert visual spatial attention in boys with attention deficit hyperactivity disorder: lateral effects,
J T Nigg1, J M Swanson, S P Hinshaw
1Department of Psychology, Michigan State University, East Lansing 48824-1117, USA. nigg@pilot.msu.edu
Insights
Boys with attention deficit hyperactivity disorder (ADHD) exhibit slower visual reaction times and left visual field processing deficits. Methylphenidate medication normalized these attention asymmetries in ADHD boys.
Area of Science:
- Neuroscience
- Developmental Psychology
- Clinical Psychology
Background:
- Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention and hyperactivity.
- Visual spatial orienting, the ability to direct attention to specific locations in space, is often impaired in individuals with ADHD.
- Understanding these deficits is crucial for developing effective interventions.
Purpose of the Study:
- To investigate covert visual spatial orienting in boys with ADHD compared to typically developing boys.
- To examine the effects of methylphenidate on visual spatial orienting in ADHD.
- To explore potential familial contributions to attention asymmetries by studying biological and adoptive parents of children with ADHD.
Main Methods:
- Three studies were conducted: 1) comparing ADHD and control boys on a visual orienting task, 2) a dose-response study of methylphenidate in ADHD boys, and 3) an investigation of parents.
- Participants included boys aged 6-12 with ADHD (n=27) and comparison boys (n=17), along with their biological (n=16) and adoptive (n=12) parents, and biological parents of comparison boys (n=14).
- Covert visual spatial orienting was assessed using reaction times to cued and uncued targets in left and right visual fields.
Main Results:
- ADHD boys showed overall slower reaction times and specific deficits in orienting to uncued targets in the left visual field compared to the right.
- Methylphenidate treatment normalized visual field responses to uncued targets and altered cue responsivity, indicating a dose-dependent effect.
- Biological parents of ADHD boys exhibited similar, though less pronounced, visual field asymmetries in reaction times, which were not observed in adoptive parents or parents of control children.
Conclusions:
- Boys with ADHD demonstrate abnormal covert visual spatial orienting, characterized by slower responses and left visual field processing biases.
- Methylphenidate effectively mitigates these attentional asymmetries in ADHD.
- The findings suggest a potential genetic influence on hemispheric asymmetry of attention functions in ADHD, observable in biological parents.
Abstract:
We report three related studies of covert visual spatial orienting in child attention deficit hyperactivity disorder (ADHD). In Study 1, we examined covert visual spatial orienting in ADHD and comparison boys, Study 2 comprised a dose-response study of methylphenidate for the ADHD group, and Study 3 was an investigation of biological and adoptive parents. In contrast with comparison subjects (n = 17). ADHD boys aged 6-12 (n = 27) showed both slower reaction times overall and within-condition (lateral) asymmetries in reaction times. Specifically, boys with ADHD reacted more slowly to uncued targets in the left visual field than in the right visual field. Responses to stimuli in the two visual fields were differentially affected by methylphenidate for the ADHD group. Medication equalized visual field responses to the uncued targets, resulting in a significant cue x dose x visual field interaction. Further, medication altered the relative cue responsivity in the two visual fields, resulting in a significant dose x visual field interaction for the Validity Effect. Biological parents of ADHD boys (n = 16) also showed slower reaction times to uncued left visual field targets than to right visual field targets; in addition they showed slower response to invalidity cued targets in the right visual field. These literal effects were not observed in adoptive parents of ADHD boys (n = 12) or biological parents of comparison boys (n = 14). Possible abnormal hemispheric asymmetry of attention functions in boys with ADHD and their biological parents is discussed.