Putamen Lesions and the Development of Attention-Deficit/Hyperactivity Symptomatology

Objective: To investigate the association between focal stroke lesions of the putamen and either attention-deficit/hyperactivity disorder or traits of the disorder (ADHD/Traits). Method: Twenty-five children with focal stroke lesions were studied with standardized psychiatric assessments and anatomic brain magnetic resonance imaging. The pattern of lesion overlap in subjects with ADHD/Traits was determined. Results: Fifteen of 25 subjects had ADHD/Traits. The densest area of overlapping lesions (n=7) in subjects with ADHD/Traits included the posterior ventral putamen. The median lesion volume was 9.7 cm³, and the distribution was highly skewed. Lesion volume was not associated with ADHD/Traits. Therefore the following analyses focused on the 13 subjects with lesions < 10 cm³: ADHD/Traits were exhibited in 6/7 subjects with putamen lesions versus 2/6 with no putamen lesions (Fisher exact test p=.1). Half (4/8) of the subjects with ADHD/Traits had overlapping lesions encompassing the posterior ventral putamen. None of the 5 subjects without ADHD/Traits had lesions in this empirically derived region of interest (Fisher exact test p=.1). Conclusions: Lesions within the dopamine-rich ventral putamen, which is part of the ventral or limbic striatum, tended to increase the risk of ADHD/Traits. ADHD/Traits may therefore be a disinhibition syndrome associated with dysfunction in this cortical-striato-thalamocortical loop.