Sex Differences in High-Risk Premature Infants' Asymmetric Movement Development

Abstract

High-risk premature infants are likely to show altered patterns in the development of reflexes and postural reactions. This study used the Modified-Measure of Behavioral Laterality (M-MOBL) neonatal assessment to explore differences in reflex and postural reactions among 26 male and female high-risk, premature infants born between 23 and 26 weeks gestational age. M-MOBL scores at 33-36.5 weeks were compared to those at 36.5-40 weeks of age, shortly before hospital discharge. The M-MOBL data were analyzed using the categorical method (CATMOD) repeated measures analysis of variance (ANOVAs) to compare the development of asymmetric movement patterns in: (1) non-injured and CNS-injured high-risk, premature infants, (2) control and experimental infants who received multi-sensory stimulation, and (3) male and female infants. Consistent with previously published reports of a right-(R) bias for healthy, full-term infants' movements, we found that high-risk premature females showed Rsided biases by 35-37 weeks post-conceptional age (PCA) for head turning responses and reflexes evoked by upper-body stimulation (i.e., palmar grasp, asymmetric tonic neck reflex [ATNR], incurvation). High-risk premature males, however, showed no significant difference in strength and coordination between the R-side and the left (L), as measured by the M-MOBL, in most of these upper-body movements tested at 35-37 weeks PCA. Neither premature males nor females showed asymmetries in foot and leg reflexes (placing, plantar grasp, Babinski). Healthy, full-term males did not show asymmetries in these reflexes either. However, full-term females showed R-bias. With further research, the M-MOBL may become a useful instrument for early identification of infants with atypical CNS development who later exhibit atypical laterality patterns.

Key Words:

• Sex differences
• motor development
• movement

Additional information

Notes on contributors

Mary Pope Grattan

Michael Lepp, PT, is in private practice, Associate Instructor of the Upledger Institute, and Clinical Instructor, Case Western Reserve University School of Dentistry, Cleveland, OH.

Marie McKenzie, MS, OTR, is in private practice. She was Coordinator of Occupational Therapy at Scottish Rite Hospital at the time of this study.

Heather Miller, MS, OTR/L, is currently employed by Madison County Educational Service Center, providing therapy services to the county's pre-schools. This research was completed in partial fulfillment of the requirements of an MS degree at Ohio State University.

Linda Viscardis, BA, is Team Leader and Community Development Worker, Peterborough Family Enrichment Centre. She is Co-Founder of P.R.O.S.P.E.C.T.S., a support and advocacy group for families who have children with special needs.

Debra Stewart, BSc, OT(C), is Occupational Therapist, Erinoak, Serving Young People with Physical Disabilities, Mississauga, ON, and Clinical Lecturer, School of Rehabilitation Science, McMaster University.

Janette McDougall, MA, was Project Coordinator

Kip Husted, BEd, was a parent representative on the study team.

Aviva Yochman, MA, OTR, was a student in the School of Occupational Therapy, Faculty of Medicine, The Hebrew University of Jerusalem, Israel at the time of this study.

Imelda Burgman, MA OTR/L BCP, completed her MA in Movement Sciences at Teachers College, Columbia University, and was an Occupational Therapist at The Shield Institute, Bronx, NY. She is currently Lecturer, Habilitation, School of Community Health, Faculty of Health Studies, Charles Sturt University, Albury, N.S.W., Australia.

Barbara J. Steva, OTWL, BCP, is Occupational Therapist, University of New England Community Occupational Therapy Clinic, Saco, ME. She was Director of Occupational Therapy and Therapeutic Recreation, Franciscan Children's Hospital and Rehabilitation Center, Boston, MA, when this work was completed.

Mary-Ann L. Fulks, MSc, OT(C), is Occupational Therapist, Vancouver Community Mental Health Service and Clinical Assistant Professor, School of Rehabilitation Sciences, University of British Columbia. This study was completed in partial fulfillment of a Master of Science degree.

Laura Zawacki, MS, PT, PCS, currently practices Pediatric Physical Therapy in the Chicago metropolitan area.

Judy T. Jennings holds a Certificate in PT and an MA in Special Education and has 25 years of experience as a PT working with children from infancy to high school.

Nicholas S. Payne, PhD, recently retired from 40 years of experience in statistics and data analysis at Proctor & Gamble, Cincinnati, OH. He was recently Research Fellow in Data Analysis, clarifying the needs of mothers and babies.

At the time of this study, Marianne Kratochvil, MA, was a social worker at the Glenrose Rehabilitation Hospital, Edmonton, Alberta. She has since retired.