Related Experiment Videos
Right hemisphere dysfunction in ADHD: visual hemispatial inattention and clinical subtype
T A Sandson1, K J Bachna, M D Morin
1Harvard Medical School, Boston, MA, USA. tsandson@bidmc.harvard.edu
Journal of Learning Disabilities
|October 28, 2004
Summary
Attention-deficit/hyperactivity disorder (ADHD) may involve right hemisphere dysfunction in some adults. This subset showed more left-sided errors on a cancellation test, but this did not correlate with specific ADHD subtypes or treatment responses.
Area of Science:
- Neuroscience
- Psychiatry
- Cognitive Psychology
Background:
- The link between right hemisphere dysfunction and attention-deficit/hyperactivity disorder (ADHD) is debated.
- Previous research has yielded inconsistent findings regarding this association.
Purpose of the Study:
- To investigate the presence and implications of right hemisphere dysfunction in adult patients with ADHD.
- To determine if specific patterns of errors on a visual-spatial task correlate with clinical or neuropsychological characteristics of ADHD.
Main Methods:
- A random letter cancellation test was administered to 58 adult ADHD patients (DSM-IV criteria) and 29 healthy controls.
- Performance was analyzed based on omission rates, particularly left-sided errors (L > R errors).
- Comparisons were made between ADHD subgroups and controls regarding error patterns, IQ, ADHD subtype, medication response, and neuropsychological test results.
Main Results:
- ADHD patients exhibited higher left-sided omission rates compared to controls.
- A significant percentage of ADHD patients made more left-sided than right-sided errors (L > R errors).
- ADHD patients with L > R errors had lower performance IQ scores but did not differ in ADHD subtype, medication response, or other neuropsychological measures.
Conclusions:
- The findings support the hypothesis of right hemisphere dysfunction in a subset of adult ADHD patients, indicated by L > R cancellation errors.
- This specific error pattern (L > R) is associated with lower performance IQ but does not define a distinct clinical subgroup based on current ADHD classifications or treatment outcomes.