M E Israel | PubMed Health

PubMed2001

Altered performance on an ocular fixation task in attention-deficit/hyperactivity disorder.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder without validated objective markers. Eye movement studies may be useful in providing objective criteria for characterizing the disorder. METHODS: We compared 53 children (29 girls) with ADHD to 44 healthy control children (18 girls) on a 21-sec fixation task. Large saccades (> 4 degrees ) away from the fixation point were analyzed. RESULTS: Children with ADHD made more large saccades that interrupted fixation than did control children (p =.001). Mean scores of the ADHD group did not change significantly with subsequent retesting on placebo (p =.11); however, there was poor intrasubject correlation (r =.16). CONCLUSIONS: Both boys and girls with ADHD made significantly more intrusive saccades during fixation than did control subjects, possibly reflecting intrinsic neurologic dysfunction; however, a probable "floor effect" obviates conclusions about the reliability of this measure.

Attention Deficit Disorder with Hyperactivity↗

PubMed2000

Executive function oculomotor tasks in girls with ADHD.

OBJECTIVE: To assess executive function in girls with attention-deficit/hyperactivity disorder (ADHD) using oculomotor tasks as possible trait markers for neurobiological studies. METHOD: Thirty-two girls aged 6 to 13 years with DSM-IV ADHD and 20 age-matched, normal control girls were tested on a variety of oculomotor tasks requiring attention, working memory, and response inhibition, which included smooth pursuit, delayed response, and go-no go tasks. RESULTS: Girls with ADHD performed the delayed response task correctly on 32% of trials as measured by number of memory-guided saccades, in contrast to 62% of trials for control subjects (p = .0009). Patients made twice as many commission errors to no go stimuli (p = .0001) and 3 times as many intrusion errors (saccades in the absence of go or no go stimuli; p = .004) during the go-no go task compared with controls. Smooth pursuit performance was statistically equivalent across subject groups. Repeated testing in a subgroup of 15 patients revealed substantial practice effects on go-no go performance. CONCLUSIONS: The data confirm that girls with ADHD exhibit impairments in executive function, as has been reported in boys, implying a similar pathophysiology of ADHD in both sexes. However, practice effects may limit the utility of the oculomotor go-no go task for some neurobiological studies.

Adolescent↗