Title

Relationships among childhood maltreatment, dissociation, and hemispheric organization

Date of Completion

January 2001

Keywords

Psychology, Psychobiology|Psychology, Developmental

Degree

Ph.D.

Abstract

Research exploring neuropsychological consequences of childhood maltreatment has indicated that trauma may result in lateralized brain abnormalities in children and adults with a more severe impact on the left-hemisphere. Resultant deficits in left-hemisphere functioning have been found in children, but few studies have explored behavioral differences related to lateralized abnormalities in adults. In light of this gap, the present study was an exploration of the relationship between childhood maltreatment and changes in inferred hemispheric organization in adulthood. A second focus was to explore the role that dissociation, an important consequence of childhood maltreatment, plays in the relationship between maltreatment and changes in brain organization. Dissociation was also included because of its proposed relationship with hypnotizability, in light of recent findings that hypnosis may be related to differences in hemispheric laterality. Participants were screened on a retrospective self-report measure of childhood maltreatment and a measure of dissociation. A lateralized dual task paradigm, pairing a simple motor task (index finger tapping) with left-hemisphere specific cognitive tasks, was used to measure inferred hemispheric organization. Women in the low abuse group showed more right hand compared with left hand interference, an expected pattern during performance of left-hemisphere tasks; whereas women in the high abuse group did not show a pattern of lateralized interference, with equal amounts of interference for both the left and right hands. For women there were also differences in lateralized performance that were related to level of dissociation, especially in the second testing session. Highly dissociative women, but not low dissociative women, showed more right hand interference than left hand interference while performing the left hemisphere tasks. There were no differences in lateralized interference related to an interaction between abuse and dissociation indicating that the effects of abuse occurred independent of the effects of dissociation. Findings lend support to the idea that childhood maltreatment may have long lasting effects on hemispheric organization, especially for women, that can be measured using behavioral tests such as the dual-task paradigm. These results also lend preliminary support to the hypothesis that dissociation is related to hypnotizability in terms of hemispheric organization. ^