Maltreating, Abusive Mothers May Have Neurological Similarities in Common

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According to the authors of research published in Scientific Reports, there are potential physiological changes in the brain's structure that result from child abuse. The authors note that the insights found in the study can be a significant step in developing effective strategies to prevent child abuse.¹

Prior studies, according to the investigators, demonstrate that up to 1 billion children between age 2 to 17 years experience some form of abuse or neglect every year. Most children overcome these negative experiences; however, a significant amount of evidence indicates that child abuse can continue to have lasting negative impacts on the brain and mental development even as these individuals age.¹

“In my work as a pediatrician, I have worked with both abused children and abusive caregivers. Hearing these stories about uncontrollable hitting and verbal abuse directed at children made me undertake this research,” said study author Sawa Kurata, assistant professor, Research Center for Child Mental Development, University of Fukui, Japan, in a news release. “Moreover, caregivers themselves often suffer due to their inability to stop abusive behaviors. Thus, we conducted this study with the belief that by supporting the caregivers, we could safeguard them as well as the children in their care.”¹

In a case-control design, investigators compared the brain white-matter fiber structure between maltreating mothers—mothers who were defined as being the child abuse perpetrator—and mothers in the general population to evaluate the presence or absence of brain features. Additionally, the investigators also examined white matter fiber structural features and the social and biological factors that might be associated with them (eg, childhood abuse experiences, depressive symptoms, parenting practices, and empathy) to assess any risk factors for developing a vulnerable neurobiological basis in maltreating mothers.²

Investigators enrolled a total of 11 maltreating mothers and 40 age-matched mothers for the control arm in the study. A modern imaging modality was used to assess information—based on the water molecules in the tissue—about microstructural features of the brain, including the complexity, integration, axonal density, and variability. In addition, the investigators were able to quantify patterns of water diffusion based on its directionality, whether parallel (axial) or perpendicular (radial) to the fiber, as well as the ratio between the 2, which is also called fractional anisotropy (FA).^1,2

Childhood abuse experiences were assessed using Japan’s version of the Childhood Trauma Questionnaire-Short Form (CTQ-J), and across all participants, higher total CTQ-J scores were associated with reduced FA (r = −0.35, P = .02, Power [1 − β] = 0.72) and axial diffusivity (AD; r = −0.44, P = .003, Power [1 − β] = 0.91) in the right corticospinal tract (CST). Further, among the CTQ-J subscales, there were higher scores observed for sexual abuse (r = −0.55, P = 7.6E−05, Power [1 − β] = 0.99), emotional neglect (r = −0.44, P = .0027, Power [1 − β] = 0.91), and emotional abuse (r = −0.39, P = .007, Power [1 − β] = 0.82), which were significantly associated with reduced AD. Similarly, higher scores for sexual abuse (r = −0.36, P = .01, Power [1 − β] = 0.75), emotional abuse (r = −0.30, P = .045, Power [1− β] = 0.58), physical neglect (r = − 0.32, P = .03, Power [1 − β] = 0.64), and physical abuse (r = − 0.34, P = .02, Power [1 − β] = 0.69) were associated with reduced FA values, according to the investigators.²

Further, depressive symptoms, parenting practices, and empathy were assessed using a self-rated depression scale (SDS), parenting scale (PS), and Interpersonal Reactivity Index, respectively. Across the entire study population, higher SDS scores were associated with lower AD and FA values in the right CST(AD: r = −0.45, P = .0008, Power [1 − β] = 0.92; FA: r = −0.36, P = .009, Power [1 − β] = 0.75), and there were no associations found between white-matter fiber structure and either PS or IRI. The authors note that because traumatic experiences can lead to atypical development in white-matter structures, maltreating mothers potentially form an intergenerational chain of childhood abuse.^1,2

“Based on our findings, maltreating mothers seem to be vulnerable to the control of force during actual voluntary movements. Further investigations into the topic may help in the development of evidence-based interventions and treatment policies,” noted Kurata in the news release. “In the future, we plan to promote collaboration between medicine, pharmacy, and engineering to develop new treatments, including drugs, psychotherapy, and medical devices, for parents with child-rearing difficulties. This includes the development of devices that can help maltreating caregivers control voluntary muscles and address their childhood traumatic experiences.”¹

References

1. University of Fukui. Researchers explore the neurobiological basis of child abuse by maltreating mothers. News release. June 4, 2024. Accessed June 24, 2024. https://www.eurekalert.org/news-releases/1046786

2. Kurata, S, Nishitani, S, Kawata, NYS, et al. Diffusion tensor imaging of white-matter structural features of maltreating mothers and their associations with intergenerational chain of childhood abuse. Sci Rep 14, 5671 (2024) doi:10.1038/s41598-024-53666-0