There are more than 200,000 preterm births in the United States every year. “Preterm” describes a birth that occurs before 37 weeks of pregnancy. Studies have shown that preterm birth has been associated with various impairments in children, including cognitive, motor, neurological, language, attention, and behavioral ailments. However, only a few studies have examined the effects of preterm birth on sensory processing. Sensory processing is the means by which the nervous system detects, regulates, understands, and responds to information from the senses. In a recent issue of the American Journal of Occupational Therapy, Stephanie Crozier, Jennifer Goodson, and colleagues discuss their findings regarding the adverse effects of preterm birth on sensory processing.
Crozier, Goodson, and colleagues observed a cohort of 160 children who were born “very” preterm. A birth is considered “very” preterm when the gestational age (the age of a pregnancy) is 28-32 weeks. The median gestational age of the cohort was 26 weeks, median birth weight was 823 grams (1.8 pounds), and the median length of stay in the NICU Neonatal Intensive Care Unit (NICU) was 65 days. Once the participants reached an age of four and a half years, they were brought to the Neonatal Follow-Up Program at the BC Women’s Hospital (Vancouver, British Columbia) to further participate in the study.
The principal instrument used in the study was the Short Sensory Profile, a questionnaire made up of 38 components that test reactions to stimulus in the following seven categories: Tactile Sensitivity, Taste/Smell Sensitivity, Movement Sensitivity, Underresponsive/Seeks Sensation, Auditory Filtering, Low Energy/Weak, and Visual/Auditory Sensitivity. The questionnaire was completed by the child’s caregiver, who rated the child’s responsiveness to the seven categories on a scale of 1(always) to 5 (never).
The results of the Short Sensory Profile test showed that 46% of the participants fell into the atypical range for overall sensory processing. The highest percentage of children displaying atypical behavior was observed for the “Underresponsive/Seeks Sensation” category, while the lowest atypical pattern was detected for “Taste/Smell Sensitivity.” More than 40% of the children showed more “Underresponsive” or “Sensory Seeking” than “Sensory Sensitivity,” which suggests a “high threshold for stimulation.” With a high threshold for stimulation, one must receive more stimulation than average in order to be vitalized. Moreover, more than one-third of the cohort exhibited atypical activity in Visual/Auditory, Taste/Smell, Movement, and Tactile Sensitivity, which suggests low neurological threshold. Furthermore, statistical analysis demonstrated that children who displayed atypical sensory processing patterns had a younger gestational age, lower birth weight, lower Apgar score (the evaluation of a newborn’s overall condition), more days of ventilation (additional supply of oxygen), and more time spent in the NICU.
Furthermore, statistical analysis demonstrated that children who displayed atypical sensory processing patterns had a younger gestational age, lower birth weight, lower Apgar score (the evaluation of a newborn’s overall condition), more days of ventilation (additional supply of oxygen), and more time spent in the NICU.
The results of this study reveal that four and a half year-old children who were born “very” preterm are at risk of impaired sensory processing. These results confirm the findings of a separate study conducted by Eeles and colleagues, which found atypical sensory processing patterns in two-year-old children who were born “very” preterm. Based on the results of both studies, one can conclude that preterm children continue to struggle with sensory processing throughout their lives. Further studies could be done to test the effects that preterm birth has on sensory processing patterns in teenagers and adults.
Based on the results of both studies, one can conclude that preterm children continue to struggle with sensory processing throughout their lives.
Although the aforementioned studies display similarities, other researchers have found slightly different results. For example, Wickremasinghe and colleagues found that only 39% of their cohort exhibited sensory patterns in the atypical range, as opposed to the 46% in the study performed by Crozier, Goodson, and colleagues. The relatively higher percentage of children in the atypical range could be attributed to a lower birth weight and gestational age of the cohort. Furthermore, studies have shown that additional time spent in the NICU can lead to an increased risk of atypical sensory processing development. In response to this, new standards have been implemented to improve the environment of the NICU, which reduce unpleasant stimuli and establish a more “womb-like” atmosphere. However, even with these changes in place, almost half of Crozier, Goodson, and colleagues’ cohort continued to display atypical sensory processing patterns. Yet it is noted that the cohort could have developed more extensive and severe atypical sensory processing patterns if the changes had not been made to the NICU. Further research should be done to more closely analyze the correlation between the environment of the NICU and the effects on the sensory processing patterns of the patients.
Due to the work of Crozier, Goodson, and colleagues, the scientific community has gained a better understanding of the effects of “very” preterm birth on sensory processing. Using this knowledge, more efforts can be made to improve the health of “very” preterm children. For example, occupational therapy is advised for children displaying atypical sensory processing. Occupational therapy can assist these children in developing skills to better perform their daily work. Moreover, Crozier, Goodson, and colleagues explain that sensory processing can further be affected by factors other than preterm birth, one of which is the length of stay in the NICU. Thus, various perinatal (relating to the time shortly before and after birth) elements should be assessed in order to create a most ideal environment for the child. In order to broaden the understanding of sensory processing deficits in children born preterm, research should be done to classify methods that may prevent the development of atypical sensory processing.
Crozier, S. C., Goodson, J. Z., Mackay, M. L., Synnes, A. R., Grunau, R. E., Miller, S. P., & Zwicker, J. G. (2015). Sensory Processing Patterns in Children Born Very Preterm. Am J Occup Ther American Journal of Occupational Therapy, 70(1).
Other Information Gathered From
Eeles, A. L., Anderson, P. J., Brown, N. C., Lee, K. J., Boyd, R. N., Spittle, A. J., & Doyle, L.W. (2013). Sensory Profiles Obtained from Parental Reports Correlate with Independent Assessments of Development in Very Preterm Children at 2 Years of Age. Early Human Development, 89(12), 1075-1080.
Wickremasinghe, A. C., Rogers, E. E., Johnson, B. C., Shen, A., Barkovich, A. J., & Marco, E. J.(2013). Children Born Prematurely Have Atypical Sensory Profiles. J Perinatol Journal of Perinatology, 33(8), 631-635.