Neurocognitive and behavioral correlates of non-right-handedness in internationally adopted children

The incidence of non-right-handedness was assessed among a sample of international adoptees. Neurocognitive and behavioral correlates to handedness were also examined among participants. A sample of 139 international adoptees (54 males; mean age at testing = 111.4 months ± 32.9 months) underwent a comprehensive neuropsychological evaluation, assessing verbal and visual reasoning, language, memory, attention, impulse control, processing speed, academic functioning, manual dexterity, and behavioral functioning. Over 26% of participants reported non-right-handedness. Non-right- and right-handers did not differ on demographic or orphanage specific variables. The groups were found to significantly differ on behavioral indices of attention and several neurocognitive variables, including visual memory, verbal memory, and manual dexterity of the dominant hand, with non-right-handers having worse performance. Possible mechanisms for these findings are discussed.